CA2190946A1 - Liquid delivery device - Google Patents
Liquid delivery deviceInfo
- Publication number
- CA2190946A1 CA2190946A1 CA 2190946 CA2190946A CA2190946A1 CA 2190946 A1 CA2190946 A1 CA 2190946A1 CA 2190946 CA2190946 CA 2190946 CA 2190946 A CA2190946 A CA 2190946A CA 2190946 A1 CA2190946 A1 CA 2190946A1
- Authority
- CA
- Canada
- Prior art keywords
- liquid
- pressure
- chamber
- outlet
- reservoir
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/168—Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body
- A61M5/16831—Monitoring, detecting, signalling or eliminating infusion flow anomalies
- A61M5/16854—Monitoring, detecting, signalling or eliminating infusion flow anomalies by monitoring line pressure
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/142—Pressure infusion, e.g. using pumps
- A61M5/145—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons
- A61M5/14586—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons pressurised by means of a flexible diaphragm
- A61M5/14593—Pressure infusion, e.g. using pumps using pressurised reservoirs, e.g. pressurised by means of pistons pressurised by means of a flexible diaphragm the diaphragm being actuated by fluid pressure
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P13/00—Indicating or recording presence, absence, or direction, of movement
- G01P13/0006—Indicating or recording presence, absence, or direction, of movement of fluids or of granulous or powder-like substances
- G01P13/0066—Indicating or recording presence, absence, or direction, of movement of fluids or of granulous or powder-like substances by using differences of pressure in the fluid
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/142—Pressure infusion, e.g. using pumps
- A61M2005/14204—Pressure infusion, e.g. using pumps with gas-producing electrochemical cell
Landscapes
- Health & Medical Sciences (AREA)
- Hematology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Vascular Medicine (AREA)
- Engineering & Computer Science (AREA)
- Anesthesiology (AREA)
- Biomedical Technology (AREA)
- Veterinary Medicine (AREA)
- Physics & Mathematics (AREA)
- Heart & Thoracic Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Infusion, Injection, And Reservoir Apparatuses (AREA)
Abstract
A liquid delivery device (10) particularly useful for delivering drugs in a liquid form, comprising a pressure-control chamber (18) having an electrolytic cell (22) therein and a reservoir (17) for the liquid separated from the pressure-control chamber (18) by a displaceable diaphragm (15). When sufficient pressure is generated within the pressure-control chamber (18) and reservoir (19), a second diaphragm (16) is raised to allow liquid to escape from the device, via an opening (26), through an outlet tube (20). The device (10) also includes a compensation chamber (19) which adjusts the rate of flow of the liquid in response to variations in ambient temperature and pressure. There is provided a pressure sensor (21) in the form of a sensor chamber (27) for immediately detecting an interruption in the flow of liquid from the device as an increase in pressure in the outlet tube (20) with respect to the pressure within the compensation chamber (19) and hence the reservoir (17). The means (21) for detecting an interruption in the delivery of liquid does not rely on the increase in pressure occurring as a result of continued gas generation.
Description
2 t 9 0 9 4 6 P~l/ll 5 ~ r r icluid deliverv deYice TFrhnir~l FiF'l~
The present invention relates to liquid delivery devices and systems, and, in particular, to devices and systems for delive~ing S liquids cr)nt:linin~ drugs. The drugs may be in solution and/or s~l~r~n~ n in a r~ rc-" ir Illy acc~ medium which is in the liquid state or the drugs may ~ ll;,el~,s be liquids.
B~ck~round Art Such devices are described in, for example, U.S. Patent 0 Spçrifir itirm Nos. 5,062,834; 5,090,963; 5,186,805; and 5,242,406.
The device described in U.S. Patent Sperifir~ti~ n No. 5,242,406 cc.",l" ;c~.i an outer housing having an outlet through which liquid is delivered, a 11;~ 1c member within the housing defining a first expansible-c~ chamber on one side of the ~
15 member for holding a supply of the material to be delivered via the outlet, and a second cA~ lc-c~ntr?~tihle charnber on the opposite side of the ~ r~ lF member. The device further C~,ll-L,li~;s pressure-control means for controlling the pressure produced in the second ~ -c~ IF chamber, and thereby the rate of flow of 20 the liquid via the outlet. The pressure control means may include an electrolytic cell for supplying a gas to the second chamber.
Means are included to minimize or eliminate the sc,.~i~ivily of the rate of flow of the liquid (which is preferably a drug) via the outlet to variations in ambient pressure and Ir~ c.
25 A disadvantage of such a liquid delivery device is that when the flow of liquid out of the unit is interrupted, the user is not ir~ y alerted to the interruption in order that c~ , measures can be taken speedily.
2 1 qO946 wo g5132013 r~ , s~
During normal operations, it may occur that the flow of liquid is urlintentionally i~ L,t~,d. For example, the tube leading from the outlet may develop a kink or may become clogged. It is illlpUlklll~ to alert the user, or those attending to the user, of the occurrence of such S an event since the lln~lPtpctpd cessation of the flow of mP(iir~tir,rl could entail highly adverse conc~qllPnrpc to the patient's well being.
Although the device described in U.S. Patent Sperifir~ n No.
5,242,406 is provided, irl certain Pnnho.li",~ with an occlusion alarm for in~ tin~ a blockage, the ",. I,~ ,,, used to detect the interruption 10 irl the flow of liquid does not ~c.. ~ ll the objective of providing an i"".,~ in-lir~tjnn of a blockage. This is because the sensor c.~'1" ic~ ~ a pressure-sensitive resistor and a contact linked to a ~i~rhra~m c~,,,,l., i~;.,p part of the wall of the pressure-control chamber. An increase in pressure within the chamber results in the 15 exertion of an a~1rlitif~n~1 force against the walls of the chamber, such that the ~liqrhr~m is pushed outwards and the contact provides irlcreased pressure against the pressure s~ , resistor. The signal from the pressure-sensitive resistor can be used to trigger an alarm warning.
If a blockage occurs in the device or the outlet tube, the pressure-control chamber is prevented from lo~pq-~linp further, with the result that c~ntimlPd 1, ~ i"-) of gas leads to an increase in pressure. In time, this is detected by the pressurc-s~ , resistor. If the normal operating pressure within the pressure-control chamber is Pl arld the pressure at which the alarm is triggered is P2, the time taken for the pressure to increasP from Pl to P2 will largely depend on the volume of the pressure-control chamber when the blockage occurs.
If the pressure-control chamber has expanded c~-nQi~lP~hly after a long period of opPr~tion, then there may be an ill~l,' delay between the interruption of the flow of liquid and the triggering of the alarm since a relatively large amount of gas will need to be generated in order to provide the required increase in pressure. This may have irnrli~:ltir,nc for the health of a patient or the efficacy of the treatment.
2l 90946
The present invention relates to liquid delivery devices and systems, and, in particular, to devices and systems for delive~ing S liquids cr)nt:linin~ drugs. The drugs may be in solution and/or s~l~r~n~ n in a r~ rc-" ir Illy acc~ medium which is in the liquid state or the drugs may ~ ll;,el~,s be liquids.
B~ck~round Art Such devices are described in, for example, U.S. Patent 0 Spçrifir itirm Nos. 5,062,834; 5,090,963; 5,186,805; and 5,242,406.
The device described in U.S. Patent Sperifir~ti~ n No. 5,242,406 cc.",l" ;c~.i an outer housing having an outlet through which liquid is delivered, a 11;~ 1c member within the housing defining a first expansible-c~ chamber on one side of the ~
15 member for holding a supply of the material to be delivered via the outlet, and a second cA~ lc-c~ntr?~tihle charnber on the opposite side of the ~ r~ lF member. The device further C~,ll-L,li~;s pressure-control means for controlling the pressure produced in the second ~ -c~ IF chamber, and thereby the rate of flow of 20 the liquid via the outlet. The pressure control means may include an electrolytic cell for supplying a gas to the second chamber.
Means are included to minimize or eliminate the sc,.~i~ivily of the rate of flow of the liquid (which is preferably a drug) via the outlet to variations in ambient pressure and Ir~ c.
25 A disadvantage of such a liquid delivery device is that when the flow of liquid out of the unit is interrupted, the user is not ir~ y alerted to the interruption in order that c~ , measures can be taken speedily.
2 1 qO946 wo g5132013 r~ , s~
During normal operations, it may occur that the flow of liquid is urlintentionally i~ L,t~,d. For example, the tube leading from the outlet may develop a kink or may become clogged. It is illlpUlklll~ to alert the user, or those attending to the user, of the occurrence of such S an event since the lln~lPtpctpd cessation of the flow of mP(iir~tir,rl could entail highly adverse conc~qllPnrpc to the patient's well being.
Although the device described in U.S. Patent Sperifir~ n No.
5,242,406 is provided, irl certain Pnnho.li",~ with an occlusion alarm for in~ tin~ a blockage, the ",. I,~ ,,, used to detect the interruption 10 irl the flow of liquid does not ~c.. ~ ll the objective of providing an i"".,~ in-lir~tjnn of a blockage. This is because the sensor c.~'1" ic~ ~ a pressure-sensitive resistor and a contact linked to a ~i~rhra~m c~,,,,l., i~;.,p part of the wall of the pressure-control chamber. An increase in pressure within the chamber results in the 15 exertion of an a~1rlitif~n~1 force against the walls of the chamber, such that the ~liqrhr~m is pushed outwards and the contact provides irlcreased pressure against the pressure s~ , resistor. The signal from the pressure-sensitive resistor can be used to trigger an alarm warning.
If a blockage occurs in the device or the outlet tube, the pressure-control chamber is prevented from lo~pq-~linp further, with the result that c~ntimlPd 1, ~ i"-) of gas leads to an increase in pressure. In time, this is detected by the pressurc-s~ , resistor. If the normal operating pressure within the pressure-control chamber is Pl arld the pressure at which the alarm is triggered is P2, the time taken for the pressure to increasP from Pl to P2 will largely depend on the volume of the pressure-control chamber when the blockage occurs.
If the pressure-control chamber has expanded c~-nQi~lP~hly after a long period of opPr~tion, then there may be an ill~l,' delay between the interruption of the flow of liquid and the triggering of the alarm since a relatively large amount of gas will need to be generated in order to provide the required increase in pressure. This may have irnrli~:ltir,nc for the health of a patient or the efficacy of the treatment.
2l 90946
3 r~ 'c - I
There is thus a need for a liquid delivery device and system which can provide an i"""f~ warning that an interruption in the flow of liquid out of t,le device has occurred.
Digrl- g~re of the Invention According to the present invention there is provided a device for the delivery of liquid, c-",.~ an outer housing having an outlet through which the liquid is delivered; a first (~ 7hlt member within the housing defining, on one side thereof, an ~_x, ' '~-contractible reservoir for holding a supply of liquid to be delivered via the outlet, and on the other side thereof an expansible-co~ ible pressure-control chamber, pressure control means for controlling the pressure within the pressure-control chamber, thereby controlling the ficFI~rPmPnt of the first ,1;~ ,le member which controls, in turn, the rate of flow of the liquid via the outlet, means for adjusting the rate of flow of the liquid via the outlet to c. ~ f r for changes ir ambient t~ ."l...,.~",~ and pressure, and mearls for detecting an irlter~uption in the delivery of liquid via the outlet crlmrricin~ a pressure sensor in direct c~ "" .~ n with the liquid.
Thus, the detection of an interruption in delivery is not an 20 indirect c~ J- ~re due to the build-up of gas pressure over time, but is instead a direct co"~ e of the increase in pressure ~c with an interruption of flow of liquid from the device.
The iquid is suitably a liquid C~ lg a drug as L~ lab~
defined.
Suitably, the means for adjusting the rate of flow of the liquid G~ S an ~PYp~ngihlP-c~ la~lible ~,~""I'~ I~AI ion chamber adjacent to the outlet such that eYr~ngi~n of the c~ ion chamber tends to restrict hydraulic crlmmllnir~tion between the reservoir and the outlet.
In a preferred Pmho-limPnt the c-~"~ i"~ chamber and the reservoir are separated by a second .liCpls~rP~hlP member.
_ WO9~i/32013 21 ~3946 r~ s ~ I --.
Preferably, the device furthem u~ iscs an ûutlet tube conn~ctin~ the reservûir and the ûutlet, the pressure sensûr being in direct L-."....-- -;r-~ion with the liquid within the ûutlet tube.
The pressure exerted by a fluid within a tube is lûwer if the fluid S is in motion through the tube, all other factors being equal. Thus, an outlet tube leading from a ~I-,DDuliDe~ reservoir to the qtmosrhf re will exhibit a pressure gradient along its length. That this is so can be seen from the fact that the liquid moves along the tube in the direction of lower pressure. Therefore, the pressure must be higher within the 10 reservoir than it is within the tube as liquid flows from the reservoir to the tube.
If the tube is blocked, the reservoir and tube fûrm a closed hydraulic system in ~qllilihrillm, and so pressure is equal in all parts thereof. Thus, when a blockage has occurred, the pRSSUre of the 15 liquid within the tube equalises with the pressure of the liquid within the reservoir. The eqllqli~qtion of pressure (that is, the increase in pressure of the liquid within the tube) occurs virtually il ~ U~ly.
It can be seen, therefore, that the provision of a pressure sensor in direct association with the liquid in the outlet tube provides a means 20 fûr the illllllf~ detection of the interruption of liquid delivery. This is in contrast to the devices of the prior art in which there is nf~c~gc ~ily a conc~ delay between the oc~,ullu~.c~e of a blockage and the detection thereof, which delay may diminish the ~rf~ ~Li~ D of a treatment using such a device.
Further, preferably, the pressure sensor detects the pressure within the outlet tube as a pressure dirr~ ,e between the liquid in the outlet tube and the liquid in the reservoir.
When an interruption has occurred and the reservoir and outlet tube form a closed hydraulic system in ~qllilihrillm, the pressures are equal thrûughout the system. During delivery, however, the liquid is effectively stationary Ll~uu~lluu~ the volume of the reservoir and is l 90946 WO 95132013 2 ~ r~ s s flowing at a considerable rate through the outlet tube, such that the pressure is lower within the outlet tube, as explained above.
Since the pressure of the liquid within the device depends upon, inte~ alia, the external t~,u~eln~ulc; and AtmocrhPri-~ pressure, an S increase in the pressure of the liquid within the outlet tube does not nPCPccArily imply that an interruption has occurred (since the same effect may result from a ~ increase). If, however, an increase in ~ causes an increase in the pressure of the liquid within the outlet tube, there will be a ~ol~ olldillg increase in the 10 pressure of the liquid within the reservoir. This means that by ,,,1 ,.~.1,;,,~ the pressure difference between the outlet tube and the reservoir, a far more reliable mPrhAnicm is used to detect an irlterruption in liquid delivery, since such a ",~ ," is in~lept~ntlPnt of external ~ and pressure variations, ti~Pp~ntlin~ only on the 15 fact that the pressure in the reservoir is always higher than that in the tube when liquid is flowing.
According to a preferred embodiment, the pressure sensor c-,",~ es an c;AI~au;~ilJlC-c~ lp ~ lt; sensor chamber in hydraulic c~ "~ ;..1l with the outlet tube, and the sensor chamber and the 20 COIII11...1C ~ie~n chamber are separated by a thi~d .1~ PA~ member, such that the ~ 1 of the third licp~ '- member is .,.1. ..1 upon the pressure ~ between the c~).l.l.. .c~-l;on chamber and the sensor chamber.
The term "1.~ . ' lir" as used in this crerifirAti- n also embraces the term ''1.. IIIIA~;t'll except where the context excludes such a meaning. T_us, the pressure sensor may be separated from the outlet tube by a gas-filled space and still be col.~ ,l to be in hydraulic cf~mmllnirAt~n If the second 7icrl~reAhle member ~between the reservoir and the 30 C~Jll~ n chamber) is freely ll;~ e~ , then the pressure within the reservoir will be equal to that within the c~ on chamber.
The .1;~ of the third 1;~ e~l-le member is therefore wogSr320l3 2 1 9 0 q 4 6 F~ 5.'~ 1 --rlf.pen-lf~nt on the pressure difference between the sensor chamber (the pressure of which is d~ d~ on the pressure within the outlet tube) and the c-"~ ir~n chamber (the pressure of which is r1çpr nrlPnt on the pressure within the reservoir).
Thus, when liquid is being delivered via the outlet tube, the pressure within the outlet tube (and within the sensor chamber) is lower than the pressure within the reservoir and the ~ A~ i ~fln chamber. Suitably, and rlr pr n-1in~ upon the G~ rir"- ,~' if m of the .u~c~iv~ chambers and the ~ t...;~l;rc of the d;~ rf~hlr 10 mr.mhPrg the third displaceable member will be in a non-eq~lilihri-lm position when the liquid is being delivered. When the delivery is il~t~ u~J~ud, the pressure is equalised between the outlet tube (and hence the sensor chamber) and the reservoir (and hence the c~ I;fm chamber), and the third r~ A-~f ~ member moves to an eq~lilihrillm 15 position. The 1ll o ~ of the tbird rligpl---~ member between the non-eq~ilihrillrn and f qllilihrillm positions indicates that the delivery of liquid via the outlet tube has been ill~ lu~l~d, just a3 a ~"I.3~
.1,. .,1 of the Illrlll~ll, -lf from the eqllilihrillm position to the non-çqllilihrillm position indicates that the interr;uption has been 20 removed.
Further, preferably, the third r~icplqreAhle member includes an electrical cf n~lllrtor such that when the third rli ~ f A~ member is ~"rri, :...,lly r1icrlqr~.r1, stretched or relaxed the electrical cfmfl~ctflr comes into contact with a pair of contacts, thereby closing an electrical' 25 circuit which, in turn, provides an in~1irAtinn of the interruption of liquid delivery.
Any or all of the .1;~ e '~lr members can be selected from ,l;i~l,l,.,.~""~ . .,l,r ~-le Ill~lllbldll~,s, pistons and ela3tically or jn~lACtjl`Ally deformable partitions, most preferably .1;,.1,1",.,""~
Preferably, the pressure-control means c~""~ an electrolytic cell for supplying a ga3 to said pressure-control chamber.
~ WO 95132013 P~
Preferably, the reservoir is only in hydraulic comml-nirarinn - with the outlet when a prerl~rminPd reservoir pressure has been reached. Suitably, said hydraulic cr~mm--ni~ati--n is effected when the displacement of a rligrla~eahle mernber is sufficient to unblock an outlet S hole through which hydraulic crlmm~nir a~i- n with the outlet is pctql~l jchl~.rl If hydraulic Cb~ ;r~n between the outlet and reservoir is limited to times at which the reservoir is above a minim1-m p~ trllll;llrd pressure, then liquid delivery will occur at a more 10 predictable rate (due to the constant head of pressure). A Dll~
reduction in reservoir pressure shuts off the supply of liquid, thereby avoiding the problems ,accc- 1 with, for example, an illLla~ ~luu~
delivery system in which the liquid is not being actively supplied, in which case the supply of drug is in hydraulic cr""",..,,;. .lit~n with th~e 15 bloodstream of the patient, allowing ;"~ ",;,~ g of blood and drug.
Suitably, the device further c-,.,.l.. i~P~ a liquid delivery filter.
This removes any entrained particles in the liquid before delivery to the patient, and may also serve to remove bubbles from the liquid.
Further, preferably the device includes means for delivering the 20 liquid from the outlet to the patient. Suitably, this means C~ iD~ a liquid delivery tube having a luer lock at an end thereof.
According to the present invention, the device also includes means for; 1 ,~ the interruption of liquid delivery when such an interruption has been detected.
Suitably, the device also C~ D a display and control urlit for controlling the delivery of the liquid from the device and for displaying information regarding ~e delivery of liquid from the . device.
In a preferred ~Illbo~lilll.,.lL, there is provided a liquid delivery 30 system c~"~ a liquid delivery device as l~ lb~;r~1lc; described 21,qoq46 WO 95/32013 r~ 5~ r and a display and control unit for controlling the delivery of the liquid from the device and for displaying information regarding the delivery of liquid from the device.
BriPf Description of the Drawines S The invention is herein ~ rihe~l by way of example only, with reference to the ~rco~ yi.,g Drawings, wherein:
Fig. 1 is a side cross-sectional view of a liquid delivery device according to the present invention;
Fig. 2 is a side cross-sectional view of the device of Fig. 1 taken at right angles thereto;
Fig. 3 is an illllctr~tif-n of a detail of the device shown in Fig.
l;
Fig. 4 is a p~ , view of the liquid delivery device of Fig.
1, further including a liquid delivery tube and filter;
Fig. S is an exploded view of the various culll~ul~ of the liquid delivery device illustrated in Fig. 4;
Fig. 6 is a top plan view of a display and control unit, typically adapted to be worn on a wrist, such as might be used with the liquid delivery device of Fig. l;
Fig. 7 is a side elevation of the display and control unit of Fig. 6;
Fig. 8 iS a side elevation of the liquid delivery device of Fig. l;
Fig. 9 is an exploded view of the various culll~ullcllL~ of the display and control unit illll~tr~t~d in Fig. 6;
Fig. 10 is a side cross-sectional view of an alternative clllbodilll~ of a liquid delivery device according to the Fig. 11 is a sch~rn~tic l~ ;on of a side elevation of S certain c.~lllL~o~ L~ of the device illllctr~tr(l in Fig. 10;
Fig. 12 is a srhP~tir l.,~l,,scl,l~lion of a side elevation of the c~ illllctrr~ l in Fig. 11, when rotated through goo; and Fig. 13 is a srh~rn~tir l~l~,- .,l .l;~m of a side elevation of the C~JIII~UII~ ill i in Fig. 12, when the liquid is being delivered.
Modes for Carryin Out th~ Invention Referrirlg to Figs. 1, 2 and 3, there is shown a drug delivery device, indicated generally at lO, which includes a rigid outer housirLg 11 which is made of first, second and third sections 12,13,14, all secured together in known manner. Housing sections 12,13,14 are preferably of circular cross-section. A first ~ rhr~m 15 is clamped between the first and second housing sections 12,13. A second ",-~", 16 is clamped between the second and third housing sections 13,14.
It will be seen that first ~ rhrzl~m 15 divides the interior of housirlg 11 irlto an r~ lf-lolll~r l;lllf reservoir 17 on one side thereof and an e~ l,lf-c~ pressure-control chamber 18 on the other side thereof. It will be further seen that second ~ rhr~m 16 25 definesanr~ c-~ lr~lil,'-cblllll- ,~I;rlnchamber19betweenit and housing section 14.
As will be described more particularly below, reservoir 17 serves to hold a supply of a liquid, such as a carrier c~...l~;";"~ a drug to be delivered; pressure-control chamber 18 serves to control the rate 21 qO946 WO 95132013 1 ~ .. S'~ I --of delivery of the liquid; and C~ ;OI1 chamber 19 serves to reduce the S~;I1Di~iViLY of the delivery rate to variations in ambient pressure and l~
Housing section 14 includes an outlet tube 20 mounted therein S through which liquid is able to flow from reservoir 17 to the outside.
Housing section 14 further includes means, indicated generally at 21 and described in more detail below, for detecting the i~ lu~,lioll of liquid delivery though outlet tube 20.
Pressure-control chamber 18 between first .~ "~.c .,. 15 and 10 housing section 12 controls the l~ r~...r~.l of second ll;~ ll 16 according to the pressure produced within chamber 18, arld thereby the rate of flow of the liquid from reservoir 17 to the outlet through outlet tube 20. For this purpose, pressure-control chamber 18 includes an electrolytic cell 22, having a pair of electrodes 23 separated by an 15 electrolyte 24 capable of g~ a gas within chamber 18 according to the electrical current passing through cell 22. Electrolyte 24 is disposed within chamber 18, whereas el~ u~s 23 pass ou~ lly through housing section 12 to enable them to be c~ t d to an external electric supply, e.g., a battery with a controlling 20 microprocessor.
The drug delivery device ill ' in Figs. 1-3 operates as follows: Reservoir 17 is first I l, . ly filled with the liquid c~. -l~;-.;..~ the drug to be ~ligrPng~l This can be achieved by the m~n--f~rh-rer, or alL-,.IIdli~.,ly by the doctor or ~ - ", -- ~I by 25 injection though an injection plug 25 (Fig. 2). As the irljection ~IU~I.,DDCS, there comes a point when reservoir 17 becomes nearly filled with liquid. At this point, further injection of liquid serves to raise second ll;'t~ III 16. When .1i ~I-I..,.~... 16 has been cllffirirntly upwardly ~licp1o~ ~-1. an opening 26 in outlet tube 20 is nllcuv~..,d 30 p~.rmittin~ liquid to flow from reservoir 17 to outlet tube 20. Further injection then serves to fill outlet tube 20 which is in direct ~,~ t)n with a sensor chamber 27 (Fig. 2). Once outlet tube 20 is filled with liquid, further injection causes liquid to leave the device .. . .. . . . .. .
WO95132013 2 1 909f~ 6 10, providing a visual indicatinn that the device 10 is now completely full of the liquid and is ready for use.
When the drug is to be delivered to a patient, clc.,Llu~s 23, which are c~""k~ d to a power supply, such as a battery 28 (Fig. 1), S are energized so that an electric potential is applied to electrolyte 24 (Fig. 2) within pressure-control chamber 22. The gas generated in chamber 22 as a result of cl~;LIu, llrllli~al reactions displaces first l",.~", 15 upwards, thereby forcing out liquid from reservoir 17, via outlet tube 20, at a rate which is related to the rate of gas 10 generation in pressure-control chamber 22.
The rate of delivery of the liquid from reservoir 17 is affected not only by the rate of gas ~n~ratif)n within pressure-control cha-inber 22 but also by the arnbient ~~ alul~ and pressure prevailing at the time the device 10 is operated. Variations in the ambient l~
15 and pressure can be c~ d for as described ~ ,hlart~.
An increase in If . ~ c; will increase the pressure in pressure-control chamber 18 and via ~ 15 also increase the pressure in liquid-filled reservoir 17, tending to increase the rate of delivery of the drug. To ~ for the increased pressure in 20 reservoir 17, an air-filled ~ f rl chamber 19 is provided. An increase in ~rlll~ ; will also increase the pressure in c-,-..l....~ir~n chamber 19 tending to, ~ ly c-"..~ for the increase in pressure in reservoir 17.
It should be noted that li l-l"; ~ - ~ 15 and 16 are both freely 25 f~ ar~ea~le~ such that the pressure is equalised between reservoir 17, pressure-control cha{nber 18 and ~c~ n chamber 19. These three C~ ~ form a system in which the pressure is effectively equalised throughout.
To aler~ the user or those attending the user of the interruption 30 of the flow of liquid out of the device, the device is equipped with WO 95/32013 2 1 q ~ 9 4 6 P~
means 21 for detecting the interruption of liquid delivery through outlet tube 20.
Referring particularly to Fig. 3, it can be seen that outlet tube 20 is provided with a small hole 29 at an alJ~IulJLial~ point along its 5 length. Hole 29 allows hydraulic comm1lni~ tit~n between sensor chamber 27 and outlet tube 20. Sensor chamber 27 is preferably formed within a cullllJa~ 30 cr~nnlA~At~d to, or integrally formed with housing section 14. Sensor chamber 27 can be liquid filled or gas filled; in practice, it is likely to be air filled although a small amount of 10 liquid may enter senso} chamber 27 when outlet tube 20 is filled.
In order to properly llnrlPrctAn~l the principles of operation of sensor chamber 27, it is necessary to consider the pressures within the various CUIlllJa~ l~ of the device and the pressure dirrt;.~ ,es across the various .1;~ lA members.
Firstly, it has already been noted above that reservoir 17, pressure-control chamber 18 and cc".,~ A~;A,n chamber 19 are all separated from one another by freely .~ Ar~ ,!r l~c.,l~lalles, thereby ensuring that the pressures are equalised within each chamber. This is apparent from the fact that a pressure dir~ lce across a barrier causes 20 a force to be applied in the direction of lower pressure. If the barrier is free to move, it will do so until the pressure is equalised or until it is no longer free to move. Therefore, the reservoir 17, pressure-control chamber 18 and c.""~ ion chamber 19 form a single pressure system (the "internal system").
Secondly, sensor chamber 27 is separated from c.. "~ ;rn chamber 19 by a third .1: ~llllla~,lll 31 which is shown in Fig. 3 in its relaxed position. The ~ rhr~m 31 is relaxed when the pressures within c~-",~ n chamber 19 and sensor chamber 27 are equal. It can be seen that if the pressure is greater within c~ AI;nn chamber 19 than within sensor chamber 27, then (I;~ III 31 will be forced upwards until the pressures are equal, until the ~I;A11111r~111 carAnot move up any further, or until the elastic nature of the ll;Alllll,.~lll supplies a WOg5132013 21 qOq4~ r~ s,~ , sufficient resistive force to balance the pressure dirrt.~l,ce. A
;"~ eqllaligatit)n of pressures will cause the dia~ a~lll 31 to immP~Iia~f ly drop back to its relaxed position. The sensor chamber 27 is in hydraulic cr,mm~niration with outlet tube 20 via the smaU hole 29, S such that the pressures within outlet tube 20 and sensor chamber 27 are effectively eq~alig~l Thus, the outlet tube 20 and sensor chamber 27 form another single pressure system (the "external system").
Before the device is filled, the internal and external systems are at equal pressures (at a~mt-eph~nr pressure). The reservoir is fiUed 10 using injection plug 25; when the reservoir is fuU, further injection causes second diaphragm 16 to be pushed upwards, with the pressure steadily increasing throughout the internal system. When second .I;a~llla~ l 16 has been moved upwards to a sufficient extent, opening 26 is uncovered allowing the liquid to escape from reservoir 17 via opening 26 and outlet tube 20. The liquid fills outlet tube 20, pa~tially fiUs the aggor~ d sensor chamber 27 (via small hole 29) and finaUy emerges from the outlet tube at open end 32 thereof (the "outlet"). The liquid within reservoir 17 remains under pressure after the injection is 1. since only a miniscule amount of liquid escapes from ~e 20 newly fiUed resenoir via opening 26 before the co~regrontlin~
reduction in the volume of liquid in the reservoir 17 aUows second ,1: t~ l.- 16 to drop back by a sufficient amount to cover opening 26, thereby sealing reservoir 17 under pressure.
Although the reservoir 17, pressure-control chamber 18 and 25 ~ ) chamber 19 remain under pressure when the device is fuU (since the internal system is sealed), the external system is ât ,.1 ,,,~.~l,l,. . i~ pressure (since it is open at end 32 of outlet tube 20 to the A~ ). Therefore, third tliqrhrag,m 31 is in the raised position when the device is full, due to the pressure lirr~ ce between the 30 internal and external systems which is applied across third .I;~lll,,~,,, 31.
When gas is generated in pressure-control chamber 18, the c~ o~ lg increase in pressure is Ll~ d Lluuu~llouL the WO9~J32013 2 1 9 0 9 4 6 r~ 7s ~ . --internal system, forcing second fl;~l,l", ~", 16 upwards by a sufficient amount to uncover opening 26 and allow liquid to escape via outlet tube 20. While the pressure increases equally in both reservoir 17 and c~ fm chamber 19, the liquid filling reservoir 17 is S iulcf lll~ ible. It is for this reason that second fli~rhrA~m 16 moves upwards reducing the volume of the gas filling f ~ ion chamber 19, which is f ~ aib'-Although the external and internal systems are in hydraulicc~mmllnif Ati~ n when the device is in operation as described above, the 10 pressures do not equalise between the two systems since liquid is free to escape from end 32 of outlet tube 20. Thus, the pressure in the internal system remains at the elevated pressure required to uncover opening 26, while the pressure within the external system remains at a lower pressure due to the flow of liquid ~ uu~ . The flow of liquid 15 from the internal to the external system is indicative that the pressure within the external system is lower than that within the internal system.
Therefore, third .1;,.~.1..,.~... 31 remains raised even when the device is in use, since there is always a pressure (lirr~ between C~ ,ll chamber 19 and sensor chamber 27. Di~luc~;~ 31 will 20 only drop back to its relaxed position when the pressures equalise between the internal and external systems. This only happens if the internal and external systems are in hydraulic c~ .;f ~ ion with no net flow of liquid therefrom.
The ~I- A~ ;-... of pressures occurs when the external system 25 suffers a blockage, such as a kink in a delivery tube (not shown) leading from end 32 of outlet tube 20. In such a case, liquid flow ceases and the internal and external systems, which now form a closed hydraulic system, i.. ~ t~ Iy ~qllilihr?to The e~lllilihr~ n of pressures between the internal and external systems causes third 30 ~ ... 31 to drop to its relaxed position. This effect occurs ;..~I,...IS...~u~ly and is not (lopon-lont on the generation of further gas within pressure-control chamber 18.
WO 9~32013 r~.,~7~ 1 Referring to Fig. 3, it can be seen that third ~ rhra~m 31 is - connPctPd to a suitable mobile electrical conductor 33 which is ~I;."~"~;.".Pd to contact fixed electrical contacts 34 mounted onto CO~ IL 30 when third ~ 31 is lowered s~fficipnfly.
5 Fixed contacts 34 form a part of an electrical circuit having external terminals 35 which can be linked to an alarm circuit to provide a warning that third ~ rhra~m 31 has dropped.
Thus, WII~ ,Y~I a blockage, or oc~ c;~n, occurs, the increased pressure in outlet tube 20 and sensor chamber 27 displaces third 10 ~ rhr~m 31 and mobile culldu~LoJ 33 downward towards the eq~lilihrillnn position until mobile c.~"~ " 33 comes in contact with fixed contacts 34, at which point the circuit is closed and a signal is ""ll~d to a suitable display and control member, described in more detail below, to warn the user of the interruption of flow.
15 Closing of the circuit may also serve to cut off the electric current through electrolytic cell 22.
The liquid delivery device described above is shown in p.,.*,~uLiv~ view in Fig. 4 and in exploded view in Fig. 5. A tube 36 extends from the device, through which liquid from the outer end 32 of 20 outlet tube 20 flows to the point of delivery to the patient. Also shown in Fig. 4 is a filter 37 which serves to filter the liquid to ensure that the liquid, which is delivered to the patient via a suitable luer lock 38 for PrC~mm~ tjn~ a needle, is free of particles and the like. Filter 37 is preferably a dual-function device which both serves as an i.v. filter 25 (capable of removing 0.1 ~lm particles) and vents any air bubbles which might be present. Filter 37 may, for example, be a Pediatric IV Filter made by Filtertek of the U.S. There is also shown a battery housing 39 within which batteries 28 are stacked, as shown in Fig. 1.
The exploded view of the liquid delivery device in Fig. 5 30 includes a number of colll~ull~,llL~ which are also indicated in Figs. 1-4 and which are llulllb~ ,1 to c~ ,*Julld with those figures. In addition, there is shown a rigid disk 40 which fits over first .1;~,1",,~", 16.
Rigid disk 40 fits the central area of .1;,.1.1",.~", 16, thereby holding WO95/32013 21 ~946 r_", this portion of diaphragm 16 rigid. An increase in pressure causing )1"~" 16 to be displaced upwards therefore has an even and predictable effect since the (l;~lllllr~lll 16 and rigid disk 40 together move with a piston-like action, thereby t~l;"~ ;"~ any irreg~ ritiPs in 5 the upward ~ r~ of the ~ rhr~m This may be ihlll)ol~ll~
since it is desirable to ensure that the pressure within reservoir 17 is always constant when the drug is being delivered, thereby allowing predictable rates of delivery and reliable intlir~tiong of pressure di~ ,llccs between the internal and external systems. Since the 10 delivery pressure is that pressure at which the centre of the 1;~.1""~", 16 unblocks opening 26, rigid disk 40 ensures that the central part of the ~ rhra~m moves upwards at a rate which is ,1~ ~. ."1...,l on the pressure within reservoir 17, because disk 40 causes the majority of the area of ~ ,,, 16 to move upwards and d~wllwald~ at a constant 15 rate.
As indicated in Fig. 5, first ,l:~l)l"h~,., 15, when relaxed, is of a shape such that reservoir 17 is of minimllnn volume after m InllfPrhlre.
Filling the reservoir 17 v~a injection plug 25 forces .1: ~i,l""~,.. 15 dOwllwr~d~ SO that the volume of reservoir 17 is m~ximig~d after filling and the volume of pressure-control chamber 18 is ",;";",;~tl The reason for this r~ L~ 'l iS that reservoir 17, if air-filled after ",~ .r~ , would be unable to Prc~mmf~ ^ the liquid.
Located near the bottom of the unit is the electrolytic cell 22, which is bounded on the top and at the bottom by a pair of hydrophobic filters 41,42. Electrodes 23 extend from electrolytic cell 22 through an electrode seal 43 and through an inglll~hin~ sleeve 44 which is housed, along with batteries 28, in battery housing 39 whose bottom portion is closed off by a battery cover 45. Batteries 28 are covered at the top with a cover 46 which carries a pair of electrode contacts 47 and a battery contact 48.
A liquid delivery device according to the present invention is preferably worn on the wrist of the user. Suitably, however, the device may be worn on other body sites via a belt, for example. The WO9!i/32013 r~ ~`'r I
liquid deliYery device, which is itself preferably disposable, is in the form of a cartridge and is designed to fit into a reusable electronic display and control unit such as the unit illllctr~tPd in Figs. 6, 7 and 9.
Together, the liquid delivery device and the display and control unit 5 form a liquid delivery system. In Figs. 7 and 8, the delivery device and the display and control unit are shown in side elevation in order to illustrate how the system fits together.
Various display and control units may be cllvi~;ull.,d, accoldil-g to the p~ which need to be controlled and the information 10 which should be displayed for any particular c.lJ~lic~iùu. The illustrative unit shown in Figs. 6, 7 and 9 includes a display which is capable of showing the flow rate and the cumulative volume of liquid, either alt~ ,ly or giml~ ou;,ly. The unit, ill ~ generally at 50, includes an up scroll button 51 and a down scroll button 52 for5 selectirlg displays, as well as an enter button 53 for entering a t- - Also included are a start button 54 and a stop button 55 to start amd stop the delivery of liquid, as well as an eject button 56 to eject a spent cartridge. The display may feature an indicator to show that a cartridge is attached and that the unit is pumping. Ful~ ulc;, 20 the urlit may provide a warning of low energy in one of the batteries.
Finally, a display and control unit will include means for alerting of an occlusion which may take the form of a visual display and/or an aural alarm.
Shown in Fig. 9 is an exploded view of the ty~ica'l display and5 control unit illllctrr~-~ in Figs. 6 and 7. In addition to the c-""ro". ..
iuu~ly described wit'n respect to Figs. 6 and 7, such a unit ~l~f~ .bly includes a pair of wrist straps 57,58 which serve to attach the unit to the wrist of the user. The unit further includes a frst contact 59 which is ~Ccori~t~d with the enter button 53, start button 540 and stop button 55, and a second contact 60 which is ~Ccori~tpd with the - up scroll button 51 and the down scroll button 52. Located below the contacts are an LCD housing 61 and an LCD 62 which are positioned above a printed circuit board (PCB) 63.
WO9~J32013 2 1 9094 6 P~,IIIL _.'~ I --Situated below PCB 63 is a battery 64 to power the display and control unit as well as an alarm buzzer 65, both of whieh rest on a bottom cover 66. Bottom cover 66 includes a battery portion 67 which ~rcnmmo~l~t~c cover 46 (Fig. 8), and further includes an occlusion 5 indicator switch 68 which ~ . ~~~ ' external terminals 35.
Located il,,l,,r.l: ~ly below bottom eover 66 is a squeeze ring 69 which serves to eject the liquid delivery device 10 upon the C~ ;u of eject button 56. Thus, a display and control unit can be designed to ~cu"""o,l,.l~ a "snap-fit" cartridge (i.e. drug delivery device). When 10 the cartridge is spent it can be ejected and a fresh supply of clrug, in the form of a new cartridge, can be fitted.
Referring to Flg. 10, there is shown a drug delivery device, indicated generally at 110, similar to that described in relation to Figs.
1-5. Parts indicated in Fig. 10 which are similar to parts indicated in 15 Figs. 1-5 are denoted by reference numerals different from those used in Figs. 1-5 by a factor of 100 (e.g. 10,110; 18,118).
Thus, the device 110 includes a rigid outer housing 111 whieh is made of first, seeond and third seetions 112,113,114. A first ,1.,.~,1",.~,., 115 is elamped between the first and seeond housing 20 seetions 112,113 and a seeond ,l. l.ll,.. c,.. 116 is elamped between the seeond and third housing seetions 113,114.
The first .l;~l.l....~ ", 115 divides the interior of housing 111 into an ~Yrslneihle-c.l"l".. l;l)le reservoir 117 on one side thereof and an "l,... l;l-le pressure-eontrol ehamber 118 on the other side 25 thereof. The seeond liarhr~m 116 def1nes an expansible-cul~ .cLible e.~".~ ;on ehamber 119 between it and housing section 14.
In similar manner to the device indicted in Figs. 1-5, the device 110 includes an outlet tube 120 and an electrolytic eell 122, and a sensor ehamber 127, whieh operates in exaetly the same manner as the 30 sensor chamber previously ~l~s~riherl WO9S132013 21 ~O q46 r~ s,~
Outlet tube 120 is provided with an opening 126 through which Iiquid escapes from reservoir 117. Dld~llld~lll 116, howeYer, is of a different construction to 1iArhr~Em 16 illustrated in relation to Figs. 1-5. In the centre of the d;a~hla~;lll there is an outlet chamber 170 into S which outlet tube 120 projects. Outlet chamber 170 forms a tight seal with housing section 114 around the point where outlet tube 120 projects from housing section 114. Outlet chamber 170 is formed in a single piece with ~ -- 116 from a deformable material. The outlet chamber 170 has d- r." lllAl~lf side walls 171 and â base section 172 provided with two slits 173. In equilibrium, the slits are closed and outlet tube 120 is isolated from reservoir 117. When the device is filled, as described in relation to the device illustrated in Figs. 1-5, liquid is injected into the reservoir until the reservoir is full. Further injection causes ~ 116 to be pressed upwards. When ~liArhrâEm 116 is pressed upwards, d~,r( l l_ walls 171 partially collapse and base section 172 moves upwards to contact end 174 of outlet tube 120. Further increased pressure within reservoir 117 causes a further upward pressure to be exerted on I;A~ 116 such that slits 173 are distended and allow liquid to fill outlet chamber 170 and to escape, via outlet 126 to outlet tube 120 and sensor cha_ber 127.
Whenfillingstops,thesecond~ ,l",.~", 116dropsback slightly, allowing base section 172 to relax and slits 173 to seal. Thus, in â similar marmer to the ~ iou~ly described device, hydrâulic cnmm~lnirAA~i~)n iS only effected between the reservoir 117 and the outlet tube 120 when a ~ t, lI-;~Ifd reservoir pressure has been reached.
A rigid disk 140 is adhered to the top of (~iqrhraEm 116 to - provide it with a piston-like action similar to that ~IG~iUU~ly tlPsrrihe~1 30 In Fig. 11, there is in~lirAAt~ generally at 175, certain CUUI~UIIGIIL~ of the device of Fig. 10, viewed in â srhPmafir G.IL~Lion of a side elevation, in order to better illustrate dia~lua~lll 116, outlet chamber 170, rigid disk 140 and outlet tube 120.
WO95132013 2~ 90946 P~
The ~li51rhra~m 116 iS view at 90 to the direction in which the cross-section of Fig. 10 is viewed. Thus, only one slit 173 is visible. Broken lines show the cross-section through the centre of ~ ", 116~
outlet chamber 170 (defined by side walls 171 and base section 172) S and outlet tube 120.
In Fig. 12~ the same s.,l~ Lic ~ on of COIII~ is used, but the view is along the same direction as the cross-section viewed in Fig. 10 (and at 90 to the elevation viewed in Fig. 11).
Thus, both slits 173 are visible in part.
In Fig. 13, the same Culll~ull~,llL~ are illllcrr~Pd as in Fig. 12, although the Culll~ull.,llL~ are viewed as the liquid is being delivered from the reservoir area, indicated generally at 117, via the outlet chamber 170 to the outlet tube 120. The diaphragm 116 iS forced upwards, as indicated by the arrows, such that edge portions 176 (not 15 adhered to rigid disk 140) are stretched to allow upward lllov~,lll.,llL of the disk 140, a--L -' ~ central portion 177 and outlet chamber 170.
Base section 172 of pressure chamber 170 iS ~ V~ d from rising when it meets end 174 of outlet tube 120. The outlet chamber 170, being elastically d~,fvlllldblc as in the case of (li:lrhr~m 116, stretches 20 in response to the upward force, thereby ~lictPn~lin~ the slits 173 and allowing hydraulic to be c~L~ .,d between the reservoir 117 and the outlet chamber 170 for delivery via the outlet tube 120. The liquid is forced out of the outlet tube 120 due to the higher pressure in resenoir 117 than in outlet chamber 170 or outlet tube 120.
As the two illustrative examples show, ensuring that hydraulic comm-lni(~tirn is only effected when a pl~tlr~ d resenoir pressure has been reached is arl objective which may be achieved irl a number of ways. The ~ l l l actually used is a matter of choice 30 which may depend on ~ 5 Thus, if the choice of materials used for the ~ l"~"~ 16~116 and outlet tube 20,120 might lead to friction, the first cllll>odilll~,.lL 10 illllctr~t~Pd in Figs. 1-5 may be ""~..;I~.1~1P as there would be a chance of the ~ rhr~m jamming, so WO 95/32013 P~ 5~ r 1 that the second embodiment 110 illllctr~d would be more suitable.
Other ~ ''l/'f~ may render the first embodiment or an altemative embodiment most suitable.
There is thus a need for a liquid delivery device and system which can provide an i"""f~ warning that an interruption in the flow of liquid out of t,le device has occurred.
Digrl- g~re of the Invention According to the present invention there is provided a device for the delivery of liquid, c-",.~ an outer housing having an outlet through which the liquid is delivered; a first (~ 7hlt member within the housing defining, on one side thereof, an ~_x, ' '~-contractible reservoir for holding a supply of liquid to be delivered via the outlet, and on the other side thereof an expansible-co~ ible pressure-control chamber, pressure control means for controlling the pressure within the pressure-control chamber, thereby controlling the ficFI~rPmPnt of the first ,1;~ ,le member which controls, in turn, the rate of flow of the liquid via the outlet, means for adjusting the rate of flow of the liquid via the outlet to c. ~ f r for changes ir ambient t~ ."l...,.~",~ and pressure, and mearls for detecting an irlter~uption in the delivery of liquid via the outlet crlmrricin~ a pressure sensor in direct c~ "" .~ n with the liquid.
Thus, the detection of an interruption in delivery is not an 20 indirect c~ J- ~re due to the build-up of gas pressure over time, but is instead a direct co"~ e of the increase in pressure ~c with an interruption of flow of liquid from the device.
The iquid is suitably a liquid C~ lg a drug as L~ lab~
defined.
Suitably, the means for adjusting the rate of flow of the liquid G~ S an ~PYp~ngihlP-c~ la~lible ~,~""I'~ I~AI ion chamber adjacent to the outlet such that eYr~ngi~n of the c~ ion chamber tends to restrict hydraulic crlmmllnir~tion between the reservoir and the outlet.
In a preferred Pmho-limPnt the c-~"~ i"~ chamber and the reservoir are separated by a second .liCpls~rP~hlP member.
_ WO9~i/32013 21 ~3946 r~ s ~ I --.
Preferably, the device furthem u~ iscs an ûutlet tube conn~ctin~ the reservûir and the ûutlet, the pressure sensûr being in direct L-."....-- -;r-~ion with the liquid within the ûutlet tube.
The pressure exerted by a fluid within a tube is lûwer if the fluid S is in motion through the tube, all other factors being equal. Thus, an outlet tube leading from a ~I-,DDuliDe~ reservoir to the qtmosrhf re will exhibit a pressure gradient along its length. That this is so can be seen from the fact that the liquid moves along the tube in the direction of lower pressure. Therefore, the pressure must be higher within the 10 reservoir than it is within the tube as liquid flows from the reservoir to the tube.
If the tube is blocked, the reservoir and tube fûrm a closed hydraulic system in ~qllilihrillm, and so pressure is equal in all parts thereof. Thus, when a blockage has occurred, the pRSSUre of the 15 liquid within the tube equalises with the pressure of the liquid within the reservoir. The eqllqli~qtion of pressure (that is, the increase in pressure of the liquid within the tube) occurs virtually il ~ U~ly.
It can be seen, therefore, that the provision of a pressure sensor in direct association with the liquid in the outlet tube provides a means 20 fûr the illllllf~ detection of the interruption of liquid delivery. This is in contrast to the devices of the prior art in which there is nf~c~gc ~ily a conc~ delay between the oc~,ullu~.c~e of a blockage and the detection thereof, which delay may diminish the ~rf~ ~Li~ D of a treatment using such a device.
Further, preferably, the pressure sensor detects the pressure within the outlet tube as a pressure dirr~ ,e between the liquid in the outlet tube and the liquid in the reservoir.
When an interruption has occurred and the reservoir and outlet tube form a closed hydraulic system in ~qllilihrillm, the pressures are equal thrûughout the system. During delivery, however, the liquid is effectively stationary Ll~uu~lluu~ the volume of the reservoir and is l 90946 WO 95132013 2 ~ r~ s s flowing at a considerable rate through the outlet tube, such that the pressure is lower within the outlet tube, as explained above.
Since the pressure of the liquid within the device depends upon, inte~ alia, the external t~,u~eln~ulc; and AtmocrhPri-~ pressure, an S increase in the pressure of the liquid within the outlet tube does not nPCPccArily imply that an interruption has occurred (since the same effect may result from a ~ increase). If, however, an increase in ~ causes an increase in the pressure of the liquid within the outlet tube, there will be a ~ol~ olldillg increase in the 10 pressure of the liquid within the reservoir. This means that by ,,,1 ,.~.1,;,,~ the pressure difference between the outlet tube and the reservoir, a far more reliable mPrhAnicm is used to detect an irlterruption in liquid delivery, since such a ",~ ," is in~lept~ntlPnt of external ~ and pressure variations, ti~Pp~ntlin~ only on the 15 fact that the pressure in the reservoir is always higher than that in the tube when liquid is flowing.
According to a preferred embodiment, the pressure sensor c-,",~ es an c;AI~au;~ilJlC-c~ lp ~ lt; sensor chamber in hydraulic c~ "~ ;..1l with the outlet tube, and the sensor chamber and the 20 COIII11...1C ~ie~n chamber are separated by a thi~d .1~ PA~ member, such that the ~ 1 of the third licp~ '- member is .,.1. ..1 upon the pressure ~ between the c~).l.l.. .c~-l;on chamber and the sensor chamber.
The term "1.~ . ' lir" as used in this crerifirAti- n also embraces the term ''1.. IIIIA~;t'll except where the context excludes such a meaning. T_us, the pressure sensor may be separated from the outlet tube by a gas-filled space and still be col.~ ,l to be in hydraulic cf~mmllnirAt~n If the second 7icrl~reAhle member ~between the reservoir and the 30 C~Jll~ n chamber) is freely ll;~ e~ , then the pressure within the reservoir will be equal to that within the c~ on chamber.
The .1;~ of the third 1;~ e~l-le member is therefore wogSr320l3 2 1 9 0 q 4 6 F~ 5.'~ 1 --rlf.pen-lf~nt on the pressure difference between the sensor chamber (the pressure of which is d~ d~ on the pressure within the outlet tube) and the c-"~ ir~n chamber (the pressure of which is r1çpr nrlPnt on the pressure within the reservoir).
Thus, when liquid is being delivered via the outlet tube, the pressure within the outlet tube (and within the sensor chamber) is lower than the pressure within the reservoir and the ~ A~ i ~fln chamber. Suitably, and rlr pr n-1in~ upon the G~ rir"- ,~' if m of the .u~c~iv~ chambers and the ~ t...;~l;rc of the d;~ rf~hlr 10 mr.mhPrg the third displaceable member will be in a non-eq~lilihri-lm position when the liquid is being delivered. When the delivery is il~t~ u~J~ud, the pressure is equalised between the outlet tube (and hence the sensor chamber) and the reservoir (and hence the c~ I;fm chamber), and the third r~ A-~f ~ member moves to an eq~lilihrillm 15 position. The 1ll o ~ of the tbird rligpl---~ member between the non-eq~ilihrillrn and f qllilihrillm positions indicates that the delivery of liquid via the outlet tube has been ill~ lu~l~d, just a3 a ~"I.3~
.1,. .,1 of the Illrlll~ll, -lf from the eqllilihrillm position to the non-çqllilihrillm position indicates that the interr;uption has been 20 removed.
Further, preferably, the third r~icplqreAhle member includes an electrical cf n~lllrtor such that when the third rli ~ f A~ member is ~"rri, :...,lly r1icrlqr~.r1, stretched or relaxed the electrical cfmfl~ctflr comes into contact with a pair of contacts, thereby closing an electrical' 25 circuit which, in turn, provides an in~1irAtinn of the interruption of liquid delivery.
Any or all of the .1;~ e '~lr members can be selected from ,l;i~l,l,.,.~""~ . .,l,r ~-le Ill~lllbldll~,s, pistons and ela3tically or jn~lACtjl`Ally deformable partitions, most preferably .1;,.1,1",.,""~
Preferably, the pressure-control means c~""~ an electrolytic cell for supplying a ga3 to said pressure-control chamber.
~ WO 95132013 P~
Preferably, the reservoir is only in hydraulic comml-nirarinn - with the outlet when a prerl~rminPd reservoir pressure has been reached. Suitably, said hydraulic cr~mm--ni~ati--n is effected when the displacement of a rligrla~eahle mernber is sufficient to unblock an outlet S hole through which hydraulic crlmm~nir a~i- n with the outlet is pctql~l jchl~.rl If hydraulic Cb~ ;r~n between the outlet and reservoir is limited to times at which the reservoir is above a minim1-m p~ trllll;llrd pressure, then liquid delivery will occur at a more 10 predictable rate (due to the constant head of pressure). A Dll~
reduction in reservoir pressure shuts off the supply of liquid, thereby avoiding the problems ,accc- 1 with, for example, an illLla~ ~luu~
delivery system in which the liquid is not being actively supplied, in which case the supply of drug is in hydraulic cr""",..,,;. .lit~n with th~e 15 bloodstream of the patient, allowing ;"~ ",;,~ g of blood and drug.
Suitably, the device further c-,.,.l.. i~P~ a liquid delivery filter.
This removes any entrained particles in the liquid before delivery to the patient, and may also serve to remove bubbles from the liquid.
Further, preferably the device includes means for delivering the 20 liquid from the outlet to the patient. Suitably, this means C~ iD~ a liquid delivery tube having a luer lock at an end thereof.
According to the present invention, the device also includes means for; 1 ,~ the interruption of liquid delivery when such an interruption has been detected.
Suitably, the device also C~ D a display and control urlit for controlling the delivery of the liquid from the device and for displaying information regarding ~e delivery of liquid from the . device.
In a preferred ~Illbo~lilll.,.lL, there is provided a liquid delivery 30 system c~"~ a liquid delivery device as l~ lb~;r~1lc; described 21,qoq46 WO 95/32013 r~ 5~ r and a display and control unit for controlling the delivery of the liquid from the device and for displaying information regarding the delivery of liquid from the device.
BriPf Description of the Drawines S The invention is herein ~ rihe~l by way of example only, with reference to the ~rco~ yi.,g Drawings, wherein:
Fig. 1 is a side cross-sectional view of a liquid delivery device according to the present invention;
Fig. 2 is a side cross-sectional view of the device of Fig. 1 taken at right angles thereto;
Fig. 3 is an illllctr~tif-n of a detail of the device shown in Fig.
l;
Fig. 4 is a p~ , view of the liquid delivery device of Fig.
1, further including a liquid delivery tube and filter;
Fig. S is an exploded view of the various culll~ul~ of the liquid delivery device illustrated in Fig. 4;
Fig. 6 is a top plan view of a display and control unit, typically adapted to be worn on a wrist, such as might be used with the liquid delivery device of Fig. l;
Fig. 7 is a side elevation of the display and control unit of Fig. 6;
Fig. 8 iS a side elevation of the liquid delivery device of Fig. l;
Fig. 9 is an exploded view of the various culll~ullcllL~ of the display and control unit illll~tr~t~d in Fig. 6;
Fig. 10 is a side cross-sectional view of an alternative clllbodilll~ of a liquid delivery device according to the Fig. 11 is a sch~rn~tic l~ ;on of a side elevation of S certain c.~lllL~o~ L~ of the device illllctr~tr(l in Fig. 10;
Fig. 12 is a srhP~tir l.,~l,,scl,l~lion of a side elevation of the c~ illllctrr~ l in Fig. 11, when rotated through goo; and Fig. 13 is a srh~rn~tir l~l~,- .,l .l;~m of a side elevation of the C~JIII~UII~ ill i in Fig. 12, when the liquid is being delivered.
Modes for Carryin Out th~ Invention Referrirlg to Figs. 1, 2 and 3, there is shown a drug delivery device, indicated generally at lO, which includes a rigid outer housirLg 11 which is made of first, second and third sections 12,13,14, all secured together in known manner. Housing sections 12,13,14 are preferably of circular cross-section. A first ~ rhr~m 15 is clamped between the first and second housing sections 12,13. A second ",-~", 16 is clamped between the second and third housing sections 13,14.
It will be seen that first ~ rhrzl~m 15 divides the interior of housirlg 11 irlto an r~ lf-lolll~r l;lllf reservoir 17 on one side thereof and an e~ l,lf-c~ pressure-control chamber 18 on the other side thereof. It will be further seen that second ~ rhr~m 16 25 definesanr~ c-~ lr~lil,'-cblllll- ,~I;rlnchamber19betweenit and housing section 14.
As will be described more particularly below, reservoir 17 serves to hold a supply of a liquid, such as a carrier c~...l~;";"~ a drug to be delivered; pressure-control chamber 18 serves to control the rate 21 qO946 WO 95132013 1 ~ .. S'~ I --of delivery of the liquid; and C~ ;OI1 chamber 19 serves to reduce the S~;I1Di~iViLY of the delivery rate to variations in ambient pressure and l~
Housing section 14 includes an outlet tube 20 mounted therein S through which liquid is able to flow from reservoir 17 to the outside.
Housing section 14 further includes means, indicated generally at 21 and described in more detail below, for detecting the i~ lu~,lioll of liquid delivery though outlet tube 20.
Pressure-control chamber 18 between first .~ "~.c .,. 15 and 10 housing section 12 controls the l~ r~...r~.l of second ll;~ ll 16 according to the pressure produced within chamber 18, arld thereby the rate of flow of the liquid from reservoir 17 to the outlet through outlet tube 20. For this purpose, pressure-control chamber 18 includes an electrolytic cell 22, having a pair of electrodes 23 separated by an 15 electrolyte 24 capable of g~ a gas within chamber 18 according to the electrical current passing through cell 22. Electrolyte 24 is disposed within chamber 18, whereas el~ u~s 23 pass ou~ lly through housing section 12 to enable them to be c~ t d to an external electric supply, e.g., a battery with a controlling 20 microprocessor.
The drug delivery device ill ' in Figs. 1-3 operates as follows: Reservoir 17 is first I l, . ly filled with the liquid c~. -l~;-.;..~ the drug to be ~ligrPng~l This can be achieved by the m~n--f~rh-rer, or alL-,.IIdli~.,ly by the doctor or ~ - ", -- ~I by 25 injection though an injection plug 25 (Fig. 2). As the irljection ~IU~I.,DDCS, there comes a point when reservoir 17 becomes nearly filled with liquid. At this point, further injection of liquid serves to raise second ll;'t~ III 16. When .1i ~I-I..,.~... 16 has been cllffirirntly upwardly ~licp1o~ ~-1. an opening 26 in outlet tube 20 is nllcuv~..,d 30 p~.rmittin~ liquid to flow from reservoir 17 to outlet tube 20. Further injection then serves to fill outlet tube 20 which is in direct ~,~ t)n with a sensor chamber 27 (Fig. 2). Once outlet tube 20 is filled with liquid, further injection causes liquid to leave the device .. . .. . . . .. .
WO95132013 2 1 909f~ 6 10, providing a visual indicatinn that the device 10 is now completely full of the liquid and is ready for use.
When the drug is to be delivered to a patient, clc.,Llu~s 23, which are c~""k~ d to a power supply, such as a battery 28 (Fig. 1), S are energized so that an electric potential is applied to electrolyte 24 (Fig. 2) within pressure-control chamber 22. The gas generated in chamber 22 as a result of cl~;LIu, llrllli~al reactions displaces first l",.~", 15 upwards, thereby forcing out liquid from reservoir 17, via outlet tube 20, at a rate which is related to the rate of gas 10 generation in pressure-control chamber 22.
The rate of delivery of the liquid from reservoir 17 is affected not only by the rate of gas ~n~ratif)n within pressure-control cha-inber 22 but also by the arnbient ~~ alul~ and pressure prevailing at the time the device 10 is operated. Variations in the ambient l~
15 and pressure can be c~ d for as described ~ ,hlart~.
An increase in If . ~ c; will increase the pressure in pressure-control chamber 18 and via ~ 15 also increase the pressure in liquid-filled reservoir 17, tending to increase the rate of delivery of the drug. To ~ for the increased pressure in 20 reservoir 17, an air-filled ~ f rl chamber 19 is provided. An increase in ~rlll~ ; will also increase the pressure in c-,-..l....~ir~n chamber 19 tending to, ~ ly c-"..~ for the increase in pressure in reservoir 17.
It should be noted that li l-l"; ~ - ~ 15 and 16 are both freely 25 f~ ar~ea~le~ such that the pressure is equalised between reservoir 17, pressure-control cha{nber 18 and ~c~ n chamber 19. These three C~ ~ form a system in which the pressure is effectively equalised throughout.
To aler~ the user or those attending the user of the interruption 30 of the flow of liquid out of the device, the device is equipped with WO 95/32013 2 1 q ~ 9 4 6 P~
means 21 for detecting the interruption of liquid delivery through outlet tube 20.
Referring particularly to Fig. 3, it can be seen that outlet tube 20 is provided with a small hole 29 at an alJ~IulJLial~ point along its 5 length. Hole 29 allows hydraulic comm1lni~ tit~n between sensor chamber 27 and outlet tube 20. Sensor chamber 27 is preferably formed within a cullllJa~ 30 cr~nnlA~At~d to, or integrally formed with housing section 14. Sensor chamber 27 can be liquid filled or gas filled; in practice, it is likely to be air filled although a small amount of 10 liquid may enter senso} chamber 27 when outlet tube 20 is filled.
In order to properly llnrlPrctAn~l the principles of operation of sensor chamber 27, it is necessary to consider the pressures within the various CUIlllJa~ l~ of the device and the pressure dirrt;.~ ,es across the various .1;~ lA members.
Firstly, it has already been noted above that reservoir 17, pressure-control chamber 18 and cc".,~ A~;A,n chamber 19 are all separated from one another by freely .~ Ar~ ,!r l~c.,l~lalles, thereby ensuring that the pressures are equalised within each chamber. This is apparent from the fact that a pressure dir~ lce across a barrier causes 20 a force to be applied in the direction of lower pressure. If the barrier is free to move, it will do so until the pressure is equalised or until it is no longer free to move. Therefore, the reservoir 17, pressure-control chamber 18 and c.""~ ion chamber 19 form a single pressure system (the "internal system").
Secondly, sensor chamber 27 is separated from c.. "~ ;rn chamber 19 by a third .1: ~llllla~,lll 31 which is shown in Fig. 3 in its relaxed position. The ~ rhr~m 31 is relaxed when the pressures within c~-",~ n chamber 19 and sensor chamber 27 are equal. It can be seen that if the pressure is greater within c~ AI;nn chamber 19 than within sensor chamber 27, then (I;~ III 31 will be forced upwards until the pressures are equal, until the ~I;A11111r~111 carAnot move up any further, or until the elastic nature of the ll;Alllll,.~lll supplies a WOg5132013 21 qOq4~ r~ s,~ , sufficient resistive force to balance the pressure dirrt.~l,ce. A
;"~ eqllaligatit)n of pressures will cause the dia~ a~lll 31 to immP~Iia~f ly drop back to its relaxed position. The sensor chamber 27 is in hydraulic cr,mm~niration with outlet tube 20 via the smaU hole 29, S such that the pressures within outlet tube 20 and sensor chamber 27 are effectively eq~alig~l Thus, the outlet tube 20 and sensor chamber 27 form another single pressure system (the "external system").
Before the device is filled, the internal and external systems are at equal pressures (at a~mt-eph~nr pressure). The reservoir is fiUed 10 using injection plug 25; when the reservoir is fuU, further injection causes second diaphragm 16 to be pushed upwards, with the pressure steadily increasing throughout the internal system. When second .I;a~llla~ l 16 has been moved upwards to a sufficient extent, opening 26 is uncovered allowing the liquid to escape from reservoir 17 via opening 26 and outlet tube 20. The liquid fills outlet tube 20, pa~tially fiUs the aggor~ d sensor chamber 27 (via small hole 29) and finaUy emerges from the outlet tube at open end 32 thereof (the "outlet"). The liquid within reservoir 17 remains under pressure after the injection is 1. since only a miniscule amount of liquid escapes from ~e 20 newly fiUed resenoir via opening 26 before the co~regrontlin~
reduction in the volume of liquid in the reservoir 17 aUows second ,1: t~ l.- 16 to drop back by a sufficient amount to cover opening 26, thereby sealing reservoir 17 under pressure.
Although the reservoir 17, pressure-control chamber 18 and 25 ~ ) chamber 19 remain under pressure when the device is fuU (since the internal system is sealed), the external system is ât ,.1 ,,,~.~l,l,. . i~ pressure (since it is open at end 32 of outlet tube 20 to the A~ ). Therefore, third tliqrhrag,m 31 is in the raised position when the device is full, due to the pressure lirr~ ce between the 30 internal and external systems which is applied across third .I;~lll,,~,,, 31.
When gas is generated in pressure-control chamber 18, the c~ o~ lg increase in pressure is Ll~ d Lluuu~llouL the WO9~J32013 2 1 9 0 9 4 6 r~ 7s ~ . --internal system, forcing second fl;~l,l", ~", 16 upwards by a sufficient amount to uncover opening 26 and allow liquid to escape via outlet tube 20. While the pressure increases equally in both reservoir 17 and c~ fm chamber 19, the liquid filling reservoir 17 is S iulcf lll~ ible. It is for this reason that second fli~rhrA~m 16 moves upwards reducing the volume of the gas filling f ~ ion chamber 19, which is f ~ aib'-Although the external and internal systems are in hydraulicc~mmllnif Ati~ n when the device is in operation as described above, the 10 pressures do not equalise between the two systems since liquid is free to escape from end 32 of outlet tube 20. Thus, the pressure in the internal system remains at the elevated pressure required to uncover opening 26, while the pressure within the external system remains at a lower pressure due to the flow of liquid ~ uu~ . The flow of liquid 15 from the internal to the external system is indicative that the pressure within the external system is lower than that within the internal system.
Therefore, third .1;,.~.1..,.~... 31 remains raised even when the device is in use, since there is always a pressure (lirr~ between C~ ,ll chamber 19 and sensor chamber 27. Di~luc~;~ 31 will 20 only drop back to its relaxed position when the pressures equalise between the internal and external systems. This only happens if the internal and external systems are in hydraulic c~ .;f ~ ion with no net flow of liquid therefrom.
The ~I- A~ ;-... of pressures occurs when the external system 25 suffers a blockage, such as a kink in a delivery tube (not shown) leading from end 32 of outlet tube 20. In such a case, liquid flow ceases and the internal and external systems, which now form a closed hydraulic system, i.. ~ t~ Iy ~qllilihr?to The e~lllilihr~ n of pressures between the internal and external systems causes third 30 ~ ... 31 to drop to its relaxed position. This effect occurs ;..~I,...IS...~u~ly and is not (lopon-lont on the generation of further gas within pressure-control chamber 18.
WO 9~32013 r~.,~7~ 1 Referring to Fig. 3, it can be seen that third ~ rhra~m 31 is - connPctPd to a suitable mobile electrical conductor 33 which is ~I;."~"~;.".Pd to contact fixed electrical contacts 34 mounted onto CO~ IL 30 when third ~ 31 is lowered s~fficipnfly.
5 Fixed contacts 34 form a part of an electrical circuit having external terminals 35 which can be linked to an alarm circuit to provide a warning that third ~ rhra~m 31 has dropped.
Thus, WII~ ,Y~I a blockage, or oc~ c;~n, occurs, the increased pressure in outlet tube 20 and sensor chamber 27 displaces third 10 ~ rhr~m 31 and mobile culldu~LoJ 33 downward towards the eq~lilihrillnn position until mobile c.~"~ " 33 comes in contact with fixed contacts 34, at which point the circuit is closed and a signal is ""ll~d to a suitable display and control member, described in more detail below, to warn the user of the interruption of flow.
15 Closing of the circuit may also serve to cut off the electric current through electrolytic cell 22.
The liquid delivery device described above is shown in p.,.*,~uLiv~ view in Fig. 4 and in exploded view in Fig. 5. A tube 36 extends from the device, through which liquid from the outer end 32 of 20 outlet tube 20 flows to the point of delivery to the patient. Also shown in Fig. 4 is a filter 37 which serves to filter the liquid to ensure that the liquid, which is delivered to the patient via a suitable luer lock 38 for PrC~mm~ tjn~ a needle, is free of particles and the like. Filter 37 is preferably a dual-function device which both serves as an i.v. filter 25 (capable of removing 0.1 ~lm particles) and vents any air bubbles which might be present. Filter 37 may, for example, be a Pediatric IV Filter made by Filtertek of the U.S. There is also shown a battery housing 39 within which batteries 28 are stacked, as shown in Fig. 1.
The exploded view of the liquid delivery device in Fig. 5 30 includes a number of colll~ull~,llL~ which are also indicated in Figs. 1-4 and which are llulllb~ ,1 to c~ ,*Julld with those figures. In addition, there is shown a rigid disk 40 which fits over first .1;~,1",,~", 16.
Rigid disk 40 fits the central area of .1;,.1.1",.~", 16, thereby holding WO95/32013 21 ~946 r_", this portion of diaphragm 16 rigid. An increase in pressure causing )1"~" 16 to be displaced upwards therefore has an even and predictable effect since the (l;~lllllr~lll 16 and rigid disk 40 together move with a piston-like action, thereby t~l;"~ ;"~ any irreg~ ritiPs in 5 the upward ~ r~ of the ~ rhr~m This may be ihlll)ol~ll~
since it is desirable to ensure that the pressure within reservoir 17 is always constant when the drug is being delivered, thereby allowing predictable rates of delivery and reliable intlir~tiong of pressure di~ ,llccs between the internal and external systems. Since the 10 delivery pressure is that pressure at which the centre of the 1;~.1""~", 16 unblocks opening 26, rigid disk 40 ensures that the central part of the ~ rhra~m moves upwards at a rate which is ,1~ ~. ."1...,l on the pressure within reservoir 17, because disk 40 causes the majority of the area of ~ ,,, 16 to move upwards and d~wllwald~ at a constant 15 rate.
As indicated in Fig. 5, first ,l:~l)l"h~,., 15, when relaxed, is of a shape such that reservoir 17 is of minimllnn volume after m InllfPrhlre.
Filling the reservoir 17 v~a injection plug 25 forces .1: ~i,l""~,.. 15 dOwllwr~d~ SO that the volume of reservoir 17 is m~ximig~d after filling and the volume of pressure-control chamber 18 is ",;";",;~tl The reason for this r~ L~ 'l iS that reservoir 17, if air-filled after ",~ .r~ , would be unable to Prc~mmf~ ^ the liquid.
Located near the bottom of the unit is the electrolytic cell 22, which is bounded on the top and at the bottom by a pair of hydrophobic filters 41,42. Electrodes 23 extend from electrolytic cell 22 through an electrode seal 43 and through an inglll~hin~ sleeve 44 which is housed, along with batteries 28, in battery housing 39 whose bottom portion is closed off by a battery cover 45. Batteries 28 are covered at the top with a cover 46 which carries a pair of electrode contacts 47 and a battery contact 48.
A liquid delivery device according to the present invention is preferably worn on the wrist of the user. Suitably, however, the device may be worn on other body sites via a belt, for example. The WO9!i/32013 r~ ~`'r I
liquid deliYery device, which is itself preferably disposable, is in the form of a cartridge and is designed to fit into a reusable electronic display and control unit such as the unit illllctr~tPd in Figs. 6, 7 and 9.
Together, the liquid delivery device and the display and control unit 5 form a liquid delivery system. In Figs. 7 and 8, the delivery device and the display and control unit are shown in side elevation in order to illustrate how the system fits together.
Various display and control units may be cllvi~;ull.,d, accoldil-g to the p~ which need to be controlled and the information 10 which should be displayed for any particular c.lJ~lic~iùu. The illustrative unit shown in Figs. 6, 7 and 9 includes a display which is capable of showing the flow rate and the cumulative volume of liquid, either alt~ ,ly or giml~ ou;,ly. The unit, ill ~ generally at 50, includes an up scroll button 51 and a down scroll button 52 for5 selectirlg displays, as well as an enter button 53 for entering a t- - Also included are a start button 54 and a stop button 55 to start amd stop the delivery of liquid, as well as an eject button 56 to eject a spent cartridge. The display may feature an indicator to show that a cartridge is attached and that the unit is pumping. Ful~ ulc;, 20 the urlit may provide a warning of low energy in one of the batteries.
Finally, a display and control unit will include means for alerting of an occlusion which may take the form of a visual display and/or an aural alarm.
Shown in Fig. 9 is an exploded view of the ty~ica'l display and5 control unit illllctrr~-~ in Figs. 6 and 7. In addition to the c-""ro". ..
iuu~ly described wit'n respect to Figs. 6 and 7, such a unit ~l~f~ .bly includes a pair of wrist straps 57,58 which serve to attach the unit to the wrist of the user. The unit further includes a frst contact 59 which is ~Ccori~t~d with the enter button 53, start button 540 and stop button 55, and a second contact 60 which is ~Ccori~tpd with the - up scroll button 51 and the down scroll button 52. Located below the contacts are an LCD housing 61 and an LCD 62 which are positioned above a printed circuit board (PCB) 63.
WO9~J32013 2 1 9094 6 P~,IIIL _.'~ I --Situated below PCB 63 is a battery 64 to power the display and control unit as well as an alarm buzzer 65, both of whieh rest on a bottom cover 66. Bottom cover 66 includes a battery portion 67 which ~rcnmmo~l~t~c cover 46 (Fig. 8), and further includes an occlusion 5 indicator switch 68 which ~ . ~~~ ' external terminals 35.
Located il,,l,,r.l: ~ly below bottom eover 66 is a squeeze ring 69 which serves to eject the liquid delivery device 10 upon the C~ ;u of eject button 56. Thus, a display and control unit can be designed to ~cu"""o,l,.l~ a "snap-fit" cartridge (i.e. drug delivery device). When 10 the cartridge is spent it can be ejected and a fresh supply of clrug, in the form of a new cartridge, can be fitted.
Referring to Flg. 10, there is shown a drug delivery device, indicated generally at 110, similar to that described in relation to Figs.
1-5. Parts indicated in Fig. 10 which are similar to parts indicated in 15 Figs. 1-5 are denoted by reference numerals different from those used in Figs. 1-5 by a factor of 100 (e.g. 10,110; 18,118).
Thus, the device 110 includes a rigid outer housing 111 whieh is made of first, seeond and third seetions 112,113,114. A first ,1.,.~,1",.~,., 115 is elamped between the first and seeond housing 20 seetions 112,113 and a seeond ,l. l.ll,.. c,.. 116 is elamped between the seeond and third housing seetions 113,114.
The first .l;~l.l....~ ", 115 divides the interior of housing 111 into an ~Yrslneihle-c.l"l".. l;l)le reservoir 117 on one side thereof and an "l,... l;l-le pressure-eontrol ehamber 118 on the other side 25 thereof. The seeond liarhr~m 116 def1nes an expansible-cul~ .cLible e.~".~ ;on ehamber 119 between it and housing section 14.
In similar manner to the device indicted in Figs. 1-5, the device 110 includes an outlet tube 120 and an electrolytic eell 122, and a sensor ehamber 127, whieh operates in exaetly the same manner as the 30 sensor chamber previously ~l~s~riherl WO9S132013 21 ~O q46 r~ s,~
Outlet tube 120 is provided with an opening 126 through which Iiquid escapes from reservoir 117. Dld~llld~lll 116, howeYer, is of a different construction to 1iArhr~Em 16 illustrated in relation to Figs. 1-5. In the centre of the d;a~hla~;lll there is an outlet chamber 170 into S which outlet tube 120 projects. Outlet chamber 170 forms a tight seal with housing section 114 around the point where outlet tube 120 projects from housing section 114. Outlet chamber 170 is formed in a single piece with ~ -- 116 from a deformable material. The outlet chamber 170 has d- r." lllAl~lf side walls 171 and â base section 172 provided with two slits 173. In equilibrium, the slits are closed and outlet tube 120 is isolated from reservoir 117. When the device is filled, as described in relation to the device illustrated in Figs. 1-5, liquid is injected into the reservoir until the reservoir is full. Further injection causes ~ 116 to be pressed upwards. When ~liArhrâEm 116 is pressed upwards, d~,r( l l_ walls 171 partially collapse and base section 172 moves upwards to contact end 174 of outlet tube 120. Further increased pressure within reservoir 117 causes a further upward pressure to be exerted on I;A~ 116 such that slits 173 are distended and allow liquid to fill outlet chamber 170 and to escape, via outlet 126 to outlet tube 120 and sensor cha_ber 127.
Whenfillingstops,thesecond~ ,l",.~", 116dropsback slightly, allowing base section 172 to relax and slits 173 to seal. Thus, in â similar marmer to the ~ iou~ly described device, hydrâulic cnmm~lnirAA~i~)n iS only effected between the reservoir 117 and the outlet tube 120 when a ~ t, lI-;~Ifd reservoir pressure has been reached.
A rigid disk 140 is adhered to the top of (~iqrhraEm 116 to - provide it with a piston-like action similar to that ~IG~iUU~ly tlPsrrihe~1 30 In Fig. 11, there is in~lirAAt~ generally at 175, certain CUUI~UIIGIIL~ of the device of Fig. 10, viewed in â srhPmafir G.IL~Lion of a side elevation, in order to better illustrate dia~lua~lll 116, outlet chamber 170, rigid disk 140 and outlet tube 120.
WO95132013 2~ 90946 P~
The ~li51rhra~m 116 iS view at 90 to the direction in which the cross-section of Fig. 10 is viewed. Thus, only one slit 173 is visible. Broken lines show the cross-section through the centre of ~ ", 116~
outlet chamber 170 (defined by side walls 171 and base section 172) S and outlet tube 120.
In Fig. 12~ the same s.,l~ Lic ~ on of COIII~ is used, but the view is along the same direction as the cross-section viewed in Fig. 10 (and at 90 to the elevation viewed in Fig. 11).
Thus, both slits 173 are visible in part.
In Fig. 13, the same Culll~ull~,llL~ are illllcrr~Pd as in Fig. 12, although the Culll~ull.,llL~ are viewed as the liquid is being delivered from the reservoir area, indicated generally at 117, via the outlet chamber 170 to the outlet tube 120. The diaphragm 116 iS forced upwards, as indicated by the arrows, such that edge portions 176 (not 15 adhered to rigid disk 140) are stretched to allow upward lllov~,lll.,llL of the disk 140, a--L -' ~ central portion 177 and outlet chamber 170.
Base section 172 of pressure chamber 170 iS ~ V~ d from rising when it meets end 174 of outlet tube 120. The outlet chamber 170, being elastically d~,fvlllldblc as in the case of (li:lrhr~m 116, stretches 20 in response to the upward force, thereby ~lictPn~lin~ the slits 173 and allowing hydraulic to be c~L~ .,d between the reservoir 117 and the outlet chamber 170 for delivery via the outlet tube 120. The liquid is forced out of the outlet tube 120 due to the higher pressure in resenoir 117 than in outlet chamber 170 or outlet tube 120.
As the two illustrative examples show, ensuring that hydraulic comm-lni(~tirn is only effected when a pl~tlr~ d resenoir pressure has been reached is arl objective which may be achieved irl a number of ways. The ~ l l l actually used is a matter of choice 30 which may depend on ~ 5 Thus, if the choice of materials used for the ~ l"~"~ 16~116 and outlet tube 20,120 might lead to friction, the first cllll>odilll~,.lL 10 illllctr~t~Pd in Figs. 1-5 may be ""~..;I~.1~1P as there would be a chance of the ~ rhr~m jamming, so WO 95/32013 P~ 5~ r 1 that the second embodiment 110 illllctr~d would be more suitable.
Other ~ ''l/'f~ may render the first embodiment or an altemative embodiment most suitable.
Claims (15)
- Claims: -A device for the delivery of liquid, comprising an outer housing having an outlet through which the liquid is delivered; a first displaceable member within the housing defining, on one side thereof, an expansible-contractible reservoir for holding a supply of liquid to be delivered via the outlet, and on the other side thereof an expansible-contractible pressure-control chamber, pressure control means for controlling the pressure within the pressure-control chamber, thereby controlling the displacement of the first displaceable member which controls, in turn, the rate of flow of the liquid via the outlet, means for adjusting the rate of flow of the liquid via the outlet to compensate for changes in ambient temperature and pressure, and means for detecting an interruption in the delivery of liquid via the outlet comprising a pressure sensor in direct communication with the liquid.
- 2. A device according to Claim 1, wherein the means for adjusting the rate of flow of the liquid comprises an expansible-contractible compensation chamber adjacent to the outlet such that expansion of the compensation chamber tends to restrict hydraulic communication between the reservoir and the outlet.
- 3. A device according to Claim 2, wherein the compensating chamber and the reservoir are separated by a second displaceable.
member. - 4. A device according to any one of Claims 1-3, further comprising an outlet tube connecting the reservoir and the outlet, the pressure sensor being in direct communication with the liquid within the outlet tube.
- 5. A device according to any preceding claim, wherein the pressure sensor detects the pressure within the outlet tube as a pressure difference between the liquid in the outlet tube and the liquid in the reservoir.
- 6. A device according to Claim 5, wherein the pressure sensor comprises an expansible-contractible sensor chamber in hydraulic communication with the outlet tube, and wherein the sensor chamber and the compensation chamber are separated by a third displaceable member, such that the displaceable of the third displaceable member is dependent upon the pressure difference between the compensation chamber and the sensor chamber.
- 7. A device according to Claim 6, wherein the third displaceable member includes an electrical conductor such that when the third displaceable member is sufficiently displaced, the electrical conductor comes into contact with a pair of contacts, thereby closing an electrical circuit which, in turn, provides an indication of the interruption of liquid delivery.
- 8. A device according to any preceding claim, wherein any or all of said displaceable members are selected from diaphragms, impermeable membranes, pistons and elastically deformable partitions.
- 9. A device according to any preceding claim, wherein said pressure-control means comprises an electrolytic cell for supplying a gas to said pressure-control chamber.
- 10. A device according to any preceding claim, wherein the reservoir is only in hydraulic communication with the outlet when a predetermined reservoir pressure has been reached.
- 11. A device according to any preceding claim, further comprising a liquid delivery filter.
- 12. A device according to any preceding claim, further comprising means for delivering the liquid from the outlet to a patient.
- 13. A device according to any preceding claim, further comprising means for indicating the interruption of liquid delivery when such an interruption has been detected.
- 14. A device according to any preceding claim, further comprising a display and control unit for controlling the delivery of the liquid from the device and for displaying information regarding the delivery of liquid from the device.
- 15. A liquid delivery system comprising a liquid delivery device according to any one of Claims 1-14 and a display and control unit for controlling the delivery of the liquid from the device and for displaying information regarding the delivery of liquid from the device.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IE940416A IE70750B1 (en) | 1994-05-23 | 1994-05-23 | Liquid delivery device |
| IE940416 | 1994-05-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2190946A1 true CA2190946A1 (en) | 1995-11-30 |
Family
ID=11040409
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2190946 Abandoned CA2190946A1 (en) | 1994-05-23 | 1995-05-22 | Liquid delivery device |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0760691A1 (en) |
| JP (1) | JPH10500342A (en) |
| CA (1) | CA2190946A1 (en) |
| IE (1) | IE70750B1 (en) |
| WO (1) | WO1995032013A1 (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU3050499A (en) | 1998-03-23 | 1999-10-18 | Elan Corporation, Plc | Drug delivery device |
| WO1999062576A1 (en) * | 1998-06-04 | 1999-12-09 | Elan Corporation, Plc | Gas driven drug delivery device |
| US6458102B1 (en) * | 1999-05-28 | 2002-10-01 | Medtronic Minimed, Inc. | External gas powered programmable infusion device |
| US9033920B2 (en) | 2003-10-02 | 2015-05-19 | Medtronic, Inc. | Determining catheter status |
| US9138537B2 (en) | 2003-10-02 | 2015-09-22 | Medtronic, Inc. | Determining catheter status |
| US7896841B2 (en) | 2004-02-17 | 2011-03-01 | Children's Hospital Medical Center | Injection device for administering a vaccine |
| DE102004010843B4 (en) * | 2004-03-05 | 2009-01-29 | Disetronic Licensing Ag | Adapter and pump interface for pressure measurement for an infusion pump |
| FR2905429A1 (en) | 2006-09-04 | 2008-03-07 | Debiotech Sa | DEVICE FOR DELIVERING A LIQUID COMPRISING A PUMP AND A VALVE |
| US9044537B2 (en) | 2007-03-30 | 2015-06-02 | Medtronic, Inc. | Devices and methods for detecting catheter complications |
| US8986253B2 (en) | 2008-01-25 | 2015-03-24 | Tandem Diabetes Care, Inc. | Two chamber pumps and related methods |
| EP2898911A1 (en) * | 2008-05-08 | 2015-07-29 | MiniPumps, LLC | Implantable pumps and cannulas therefor |
| CA2921304C (en) | 2009-07-30 | 2018-06-05 | Tandem Diabetes Care, Inc. | Infusion pump system with disposable cartridge having pressure venting and pressure feedback |
| GB2484760B (en) * | 2011-03-22 | 2012-08-29 | Roger Thomas Hurrey | A hose connector |
| US9180242B2 (en) | 2012-05-17 | 2015-11-10 | Tandem Diabetes Care, Inc. | Methods and devices for multiple fluid transfer |
| US9555186B2 (en) | 2012-06-05 | 2017-01-31 | Tandem Diabetes Care, Inc. | Infusion pump system with disposable cartridge having pressure venting and pressure feedback |
| JP6102095B2 (en) * | 2012-06-26 | 2017-03-29 | セイコーエプソン株式会社 | Liquid injector and liquid injection method |
| US9173998B2 (en) | 2013-03-14 | 2015-11-03 | Tandem Diabetes Care, Inc. | System and method for detecting occlusions in an infusion pump |
| US9421329B2 (en) | 2013-03-15 | 2016-08-23 | Tandem Diabetes Care, Inc. | Infusion device occlusion detection system |
| US9180243B2 (en) | 2013-03-15 | 2015-11-10 | Tandem Diabetes Care, Inc. | Detection of infusion pump conditions |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4714462A (en) * | 1986-02-03 | 1987-12-22 | Intermedics Infusaid, Inc. | Positive pressure programmable infusion pump |
| IT1188467B (en) * | 1986-03-27 | 1988-01-14 | Intermes Spa | FLOW |
| US5242406A (en) * | 1990-10-19 | 1993-09-07 | Sil Medics Ltd. | Liquid delivery device particularly useful for delivering drugs |
-
1994
- 1994-05-23 IE IE940416A patent/IE70750B1/en unknown
-
1995
- 1995-05-22 WO PCT/IE1995/000031 patent/WO1995032013A1/en not_active Application Discontinuation
- 1995-05-22 EP EP95918137A patent/EP0760691A1/en not_active Ceased
- 1995-05-22 CA CA 2190946 patent/CA2190946A1/en not_active Abandoned
- 1995-05-22 JP JP7530172A patent/JPH10500342A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| WO1995032013A1 (en) | 1995-11-30 |
| IE70750B1 (en) | 1996-12-30 |
| IE940416A1 (en) | 1995-11-29 |
| EP0760691A1 (en) | 1997-03-12 |
| JPH10500342A (en) | 1998-01-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |