US3305097A

US3305097A - High pressure peristaltic pump for separation apparatus

Info

Publication number: US3305097A
Application number: US283491A
Authority: US
Inventors: Natelson Samuel
Original assignee: Scientific Industries Inc
Current assignee: Scientific Industries Inc
Priority date: 1963-05-27
Filing date: 1963-05-27
Publication date: 1967-02-21
Anticipated expiration: 1984-02-21

Description

Feb. 21, I967 s, N L N 3,305,097

HIGH PRESSURE PERISTALTIC PUMP FOR SEPARATION APPARATUS Filed May 27, 1963 4 Sheets-Sheet 1 z /5 (75 :1; i A

5AMUEZ. M4754 50M INVENTOR.

Feb. 21, 1967 s. NATELSON 3,305,097

HIGH PRESSURE PERISTALTIC PUMP FOR SEPARATION APPARATUS Filed May 27, 1963 4 Sheets-Sheet 73 EXIT 524 5/1MUEL M1754 50M INVENTOR.

HIGH PRESSURE PERISTALTIC PUMP FOR SEPARATION APPARATUS Filed May 27, 1963 S. NATELSON Feb. 21, 1967 4 Sheets-Sheet I A/R SUPPAY 63&

SAMUEL A/ATEL50/V INVENTOR.

SOLUT/ON /jge Feb. 21, 1967 s. NATELSON HIGH PRESSURE PERISTALTIC PUMP FOR SEPARATION APPARATUS Filed May 27, 1963 FESI'E/C 771 5 4 Sheets-Sheet 4 SAMUEL lV/l TEL 50M INVENTOR.

United States Patent 3,305,07 HIGH PRESSURE PERISTALTIC PUMP FOR SEPARATION APPARATUS Samuel Natelson, Valley Stream, N.Y., assignor to Scientific Industries Inc., Queens Village, N.Y. Filed May 27, 1963, Ser. No. 283,491 6 Claims. (Cl. 210321) The present invention refers to a peristaltic pump, and more particularly to a high pressure peristaltic pump useful in automatic chemical analysis.

The usual peristaltic pump is a roller arrangement, i.e., a tube carrying the fluid to be pumped goes through a series of rollers. Since the tube cannot be too thick onlya small amount of pressure can be applied. However, as is immediately apparent, the tube carrying the sample is about tangent to the roller. This means effectively that only a very small portion of the tube is in actual contact with the roller. Assuming that the applied pressure is 25 pounds per square inch and only a small portion of tubing A of an inch) is in contact with the roller, this provides a pressure of 250 pounds per square inch at the point of contact. Considering that the ordinary automobile tire takes about 25 to 30 pounds per square inch pressure, certainly a pressure of some 250 pounds per square inch produces a strain on the tubing and requires tubing of great strength. At the point where the roller is not pressing, the tube will blow out if pressures higher than 25 pounds per square inch exist within the tubing.

Another disadvantage of this type of arrangement is that although a high pressure is applied at one spot, such a pressure is really needed uniformly throughout the pumping station. Furthermore, when used for pumping blood there is considerable hemolysis (e.g., destruction of red cells) due to the high pressure and rubbing at the point of contact.

For these reasons peristaltic pumps capable of delivering substantially more than 25 pounds per square inch have not been possible heretofore.

A careful study of the pumping action leads the inventor to the conclusion that a peristaltic type of pump operated by compressed air or other fluid where the air or liquid will flow in waves over the rubber tubing containing the liquid to be pumped is what is required. No peristaltic pumping arrangement as far as I am aware based on this principle has ever been successful when put into practice on an industrial or commercial scale.

Therefore, an object of the present invention is to provide a peristaltic pump for the transmission of biological fluids at variable pressures.

Another object of the present invention is to provide a high pressure pump, i.e., a pump having a pressure in excess of 25 pounds per square inch.

Still another object of the present invention is to provide a gentle high pressure pump which can pump blood without rupturing the red cells of blood.

Yet another object of the present invention is to provide a high pressure pump having. a smooth easy wavelike action.

Still another object of the present invention is to provide a device useful for ultra-filtration using this pump.

With the foregoing and other objects in view, the invention resides in the novel arrangement and combination of components, and in the details of construction hereinafter described, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is described without departing from the spirit of the invention.

Broadly stated, the present invention contemplates a peristaltic pump having at least three sequential squeeze members designed to assume either an open or a squeeze position, and, means to sequentially place the last .and first, the first and second, the next-to-last and last, and again the last and first squeeze members in the squeeze position.

The advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawing in which:

FIGURE 1a to 1h illustrates schematically the theory of operation of the peristaltic pump;

FIGURE 2 shows partly in perspective and partly in cross-section, an embodiment of an apparatus designed to perform the operation illustrated in FIGURE 1 with certain portions cut-away to show the internal operation; using the principle discussed above.

FIGURE 3 depicts in a cut-away perspective a component used in the device illustrated in FIGURE 2.

FIGURE 4 illustrates schematically another embodiment of the present invention;

FIGURE 5 shows in perspective the ultra-filtration section contemplated herein;

FIGURE 6 is a perspective view of another form of one of the component assemblies contemplated herein; and,

FIGURE 7 shows in a perspective cut-away view an alternative for one of the components of the component assemblies shown in FIGURE 2.

To better understand the invention there is first depicted in the drawing FIGURE 1a to FIGURE 111 the peristaltic action of the pump herein contemplated. As shown there is a piece of tubing 11 surrounded by

squeeze members

12, 13, 14, 15. Now squeeze

members

12, 13, 14, 15 wiil operate in a staggered relationship so that when actuated they will progressively apply pressure in the desired direction of flow. In FIGURE 1a none of the squeeze members have been actuated. FIGURE 1b starts the wave train, as shown by the arrow, by actuating squeeze member 12. Next, squeeze member 13 is actuated but squeeze member 12 still remains in the actuated position. Next, squeeze member 14 is actuated in FIGURE l d releasing squeeze member 12, but keeping member 13 in the squeezed position. Finally squeeze member 15 is actuated while squeeze member 14 remains actuated, but member 13 is released. In FIGURE 1 the cycle starts over again, with

members

15 and 12 in the squeeze position while

members

13 and 14 are released. In FIGURE 1g we are back to the situation of FIGURE 1c while FIGURE 111 is a repetition of FIGURE 1d.

However, from a study of FIGURES 1a to 112, two facts are immediately apparent. First, the wave motion tends to be choppy and irregular whereas a smooth flowing wave is desired. Secondly, if air at a pressure of 150 pounds per square inch is pumped into a thin rubber tube, the tube will expand and eventually burst. This is caused by the fact that atmosphere pressure is 15 pounds per square inch while the pressure inside the tube is 150 pounds per square inch. The difference of pounds per square inch is suflicient to burst the tube. However, if the tube is encased in a solid cylinder and a pressure of pounds per square inch is applied, the tube remains undamaged. This is so because the pressure both inside and outside is the same and the difference is zero. This principle is used in the present invention. Thus, when a pressure of 150 pounds per square inch is applied to the tubing, the tubing collapses until the pressure inside is 150 pounds per square inch less the force required to crush the tube. This latter force is measured in ounces per square inch. Thus, the tubing is not subject to excessive pressure. When the pressure is released, the tube can expand only so far until it reaches a solid inner cylindrical surface. The tube can never expand to the breaking point.

To carry the present invention into practice a source of compressed gas or air 41 is used as the actuating medium. Compressed gas e.g., air from soure 41 is fed to a seal 42. The seal 42 holds a gasket 43 forming a bearing. Silicone oil is used to prevent bearing friction. Journaled for rotation in the bearing is a central gas supply tube 44 with a pulley 45 mounted axially thereon. Pulley 45 is run by a belt 46 from drive means 47. Central gas supply tube 44 leads into and rotates a stop cock 48. The stop cock may be either cylindrical or frustroconical in shape and the usual speed of rotation is about one-half revolution per second. Stop cock 4% has a first Y-channel 49 leading axially to one end of the cylinder into central tube 44. The two arms of the Y-channel lead to two outer openings 50 and 51 located at positions on the cylindrical stop cock outer surface separated by 90 circumference. From two other

open positions

52 and 53 on the cylindrical stop cock outer surface also separated by 90 from each other and from the first two openings is a second Y-channel 54 leading .to an escape opening 55 at the other end of the cylinder.

Stop cock48 rotates in a housing 480, and disposed in a circle about stop cock 48 in said housing are four

inlet ports

56, 57, 58, 59 designed to be opposite the respective openings in the stop cock of the first Y-channels. The inlet poits 56, 57, 58 and 59 lead into

hoses

69, 61, 62, 63 which in turn lead to the squeeze means. As drive means 47 rotates pulley 45 and central tube 44 connected to stop cock 48, air from compressed air source 41 is first fed to

inlet ports

56 and 57; next 57 and 58, next 55 and 59, next 59 and 56 and again to

inlet ports

56 and 57. The air therefore is pumped into squeeze members 67 and 64; 64 and 65; 65 and 66; 66 and 67; and again into squeeze members 67 and 64 through

hoses

66, 61, 62 and 63. As shown in the drawing each squeeze mem- ,

ber

64, 65, 66 and 67 has a tapered flexible rubber inner jacket 68 and a firm metal or plastic outer jacket 69. While uniform flexible inner jackets may be used the tapered design gives a smoother action. The inner jacket is fitted into the outer jacket, and both inner and outer jackets have flanged ends 70 and 71. When the inner jacket is pulled through the outer jacket, the inner flanged ends will stick out and be disposed alongside the corresponding outer flanged ends of the outer jacket as shown. The flanged ends are held together by fastening means, e.g., bolts 73 or are sealed together. Thus the combination of inner and

outer jackets

63 and 69 form a chamber 68a. The air from the

hoses

60, 61, 62, 63 enters chamber 68a and presses out the thinner portion of tapered inner jacket 68 against hose 11. Gradually the air pressure also presses out the thicker portion of inner jacket 68. This provides a gradual smooth peristaltic squeeze pressure in the desired direction of travel, i.e., from 64 to 65; from 65 to 66; from 66 to 67. Tube 11 which carries the sample 17 is made of thin rubber and enters the pump at the entrance 18 to the first squeeze member 64 and goes right through the pump into a copper tube 73, the end 19 of the rubber tube 11 being shown as going partly up the elbow of the copper tube 73. At the state of rest without any sample going through the pump, there is a very small clearance between the outer face of tube 11 and the corresponding face of inner jacket 68. Effectively, at rest, there are two clearances, that between inner and

outer jackets

68 and 69 which form chamber 68a, and that between inner jacket 68 and tube 11. The air entering the chamber 68a from the

hoses

60, 61, 62, 63 enlarges chamber 68a so that the inner jacket presses on the tube forcing the liquid in the tube to go on to the next squeeze member. As the openings of the first Y-channel are respectively feeding air into

hoses

60, 61; 61, 62; 62, 63; and 63, 61 the openings of the second Y-channel are appearing

opposite inlet ports

56, 57, 58 and 59 allowing the air in the squeeze members to escape thus providing for the sequential operation of the pump. This pumping action of the squeeze members generates some heat so that cooling means, i.e., fins 72 are provided on each squeeze member. The pump discharges into an autoclave attached to the copper tube or in the application shown in FIGURE 2 discharges into a copper tube 73 lined with the rubber tubing leading to an ultra-filtration section inlet 80.

The ultra-filtration section includes a lower spiral 74 and an upper spiral 75. The two spirals, 74 and 75 are disposed one alongside the other inlet leads to the center of the lower spiral '74. Separating the two spirals is a membrane 76, and at the outer ends of bothspirals are lower and upper discharge spiggots 77 and 78. As the sample fluid is pumped into the ultra-filtration section a separation takes place through the membrane due to the difference in pressure so that the concentration of substances which will not pass through the membrane, e.g., protein is increased in the lower spiral. Other substances, e.g., salts will pass through the membrane and will provide the same concentration in both spirals. This ultrafiltration facilitates subsequent processing and identifica: tion of the sample. To maintain the high pressure in the lower spiral a restrictive valve 79 controls the outflow from lower discharge spiggot 77. A second restrictive valve 7% controls the outflow from upper discharge spiggot '78.

Opposite high filtration inlet 80 there is an upper spiral opening 81 shown in the drawing as being closed by a stopper 82. This opening is normally used to flush the upper spiral for cleaning by passing water through tube 82a shown as not being connected to the ultra-filtration section. When stopper 82 is removed, and tube 82a is connected to the ultra-filtration section, the device can also be used for dialysis and controlled diffusion of collodial substances through the membrane, or a combination of ultra-filtration and dialysis by continuously passing a solution of water through the upper spiral. Thus, substances can be fed to the upper spiral through tube 82a, and the amount of each substance in the upper and lower spiral will depend not only on the molecular size of the substances but also on the pressures at which the substances are fed into the lower spiral. Although when at the same pressure, the greater flow of water is in the direction of the highest concentration, this tendency can be reversed by changing the pressure at which the substances are fed on both sides of the spiral so that the osmotic pressure is exceeded. Thus if sea water (3.5%) is pumped at high pressures through the lower spiral and a flow of diluted sea water comes through the upper spiral (2.5%) and a membrane is used which passes Water freely but impedes the movement of salt, then at high pressures the sea water will exit at 77 at higher than initial concentration (e.g., 5% salt) and the water exiting at 78 from the upper spiral will be diluted correspondingly.

The pump of FIGURE 2 is entirely air driven. This is particularly useful in hospitals when working in the vicinity of an oxygen tent. But, as shown in the drawing, an electromechanical arrangement is also possible. there is shown a pump and four squeeze members, 64a, 65a, 66a, 67a, corresponding to the respective components similarly numbered in the previous embodiment. In this arrangement air supply 41a is coupled directly to each squeeze member through

feed lines

600, 61a, 62a, and 63a. At the same time, each squeeze member has an air outlet, 646, 656, 660 and 670, as is evident, if the feed line is closed and the outlet is open, the squeeze member is in the open position. If the feed line is open and the outlet is closed, air penetrates into the squeeze member forcing it into the squeeze position. Associated with each feed line and outlet is a

valve pair arrangement

641, 651, 661 and 671 each valve pair has two valves, 642, 643; 653', 662, 663; 672, 673. The valves are so disposed that if one valve in the pair is open, the other valve in the pair is shut. For simplicity of explanation, the arrangement is depicted schematically in the drawing. The valve pairs are actuated by means of electromagnetic relays 90,

Here

91, 92, 93 coupled in

closed circuits

94, 95, 96, 97 each closed circuit being shown as a

battery

98, 99, 100, 101, and a

switch

102, 103, 104, 105. The switches are actuated by an eccentric cam 106 driven by a motor M.

Since as shown, two succeeding electromagnetic relays are always coupled in one circuit when the cam actuates a switch it will activate two relays at a time thus acting on two succeeding valve pairs so as to move the squeeze members from the open to the squeeze position, i.e., relays 90, 91, 92, 93; will close

valves

673 and 643; 643 and 653; 653 and 663; 663 and 673. At the same time the relays will open valves 672 and 642; 642 and 652; and 662; 662 and 672. This will close outlets 670 and 640; 640 and 650; 650 and 660; 660 and 670, and allow air to flow to the respective squeeze members placing them in the squeeze position.

Based upon the foregoing principles, it is also possible to construct a pump which will act on a plurality of tubes as shown in the drawing. The arrangement shown for a plurality of tubes is built like the device for a single tube except that the device for a single tube has a round aperture, whereas in the device for a plurality of tubes the aperture is in a rectangular shape. Thus, there is an outer jacket 111 with flanged ends 112, and fins 113. Inner jacket 114 has flanged ends 115 which will mate with the outer jacket flanged ends 112. The inner jacket is tapered towards one end so as to provide the smooth gradual peristaltic action desired.

It is to be observed therefore that the present invention provides for a peristaltic pump for delivering fluids at high pressure and comprises at least three sequential longitudinally aligned squeeze members designed to assume either an open or squeeze position, and pneumatic or compressed air means to simultaneous sequentially and gradually squeeze in progression, the last and first, the first and second, the next to last and last, and again the last and first squeeze members, the gradual squeezing being in the direction of delivery. Preferably the device has at least four squeeze members. The squeeze members contemplated herein include a hollow solid flanged outer jacket, a hollow tapered resilient flanged inner jacket, disposed within and in engagement with said outer jacket, the flanges of said inner and outer jackets being disposed alongside one another and fastened together, so that said inner and outer jackets form a closed chamber. A feed line is coupled to said chamber for feeding compressed air thereto, so that a gradual squeezing action is caused by said tapered inner jacket. Preferably, said compressed air means includes a bearing designed to receive a gas under pressure; a central gas supply tube journaled for rotation in the bearing; rotary drive means to rotate said central gas supply tube; a cylinder rotated by said central gas supply tube including a first Y-channel therein leading from said central gas supply tube to two outer openings in the cylinder circumference separated by 90 and a second Y-channel leading from two other openings on said cylinder circumference also separted from each other and from the first two openings by 90, to an escape opening in said cylinder; and four inlet ports leading to each of said squeeze means disposed 90 apart circumferentially about said cylinder so that periodically two of said ports are opposed to two outer openings in one of said Y-c-hannels while the other two are opposed to the openings in the other said Y-channels.

Furthermore, the present invention contemplates an ultra-filtration section for the foregoing apparatus and includes an inlet fed by the peristaltic pump section, which inlet leads into the center of a lower spiral. Alongside said lower spiral is an upper spiral separated from the lower spiral by a membrane. At the outer ends of the two spirals are outlets. Substances fed to the ultra-filtration section by the peristaltic pump section will pass to the lower spiral where material incapable of passing through the membrane will not pass to the upper spiral thus increasing the concentration thereof in the lower spiral. The ultra-filtration section can be used for dialysis or a combination of dialysis and ultra-filtration by cou pling a tube to the upper spiral opposite the inlet.

The reason why high pressures are attainable in the peristaltic pump is that the tubing is not exposed to the atmosphere and the applied pressure actually amounts to ounces per square inch because of the gradual smooth squeezing action. Furthermore the pump provides a continuous supply to the ultra-filtration section as opposed to the batch ultra-filtration methods of the prior art.

It is further to be observed that as used herein the term compressed air includes compressed water, oil, steam or other gases which may be used for the pneumatic actuation of the squeeze members.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

I claim:

1. A peristaltic pump for delivering fluids in even flow thnough a flexible tube at high pressure to a high pressure chamber comprising in combination, at least three sequential longitudinally aligned squeeze members designed to assume either an open or squeeze position, pneumatic means connected to said pump to simultaneously sequentially and gradually squeeze in progression, the last and first, the first and second, the next to the last and last, and again the last and first squeeze members, the gradual squeezing being in the direction of delivery, each of said squeeze members comprising a hollow solid flanged elongated outer jacket, a hollow resilient flanged, tapered-Wall inner jacket, said tapering being such that the wall tapers counter to the flow direction of the fluid being pumped, said tapered wall inner jacket being disposed within and in engagement with said outer jacket, the flanges of said inner and outer jackets being disposed alongside one another and fastened together so that the inner and outer jackets form a closed chamber when inflated by said pneumatic means, an outlet section including a rigid tube connected rigidly at one end to a high pressure chamber and at the other end rigidly connected to the flange of the outer jacket disposed on the delivery end of the last of said squeeze members, said flexible tube being encased in said rigid tube and therein outwardly supported to prevent its bursting, and feed lines coupling said pneumatic means to each of said chambers.

2. A device as claimed in claim 1, said pneumatic means including a bearing designed to receive a gas under pressure; a central gas supply tube journaled for rotation in the bearing; rotary drive means to rotate said central gas supply tube; a cylinder rotated by said central gas supply tube including a first Y-channel therein leading from said central gas supply tube to two :outer openings in the cylinder circumference separated by and a second Y-channel leading from two other openings on said cylinder circumference also separated from each other and from the first two openings by 90, to an escape opening in said cylinder; and four inlet ports in said feed lines leading to each of said chambers disposed 90 apart circumferentially about said cylinder so that periodically two of said ports are opposed to two outer openings in one of said Y-c'hannels while the other two are opposed to the openings in the other of said Y-channels while the other two are opposed to the openings in the other of said Y-channels.

3. A device as claimed in claim 1, said pneumatic means including an outlet coupled to each of said chambers, blocking means associated with the feed lines and outlet for each of said chambers designed to assume one of two positions, blocking said opening in the one position and said feed line in the other position, and progression 7 actuating means sequentially causing said blocking means to block the last and first outlet, the first and second outlet, the next to the last and last outlet and again the last and first outlet thereby carrying out the peristaltic squeezing action of said pump.

4. A device as claimed in claim 1, said high pressure chamber being the input side of an ultra-filtration apparatus which comprises an input side with a lower spiral coupled at the spiral center to said outlet section; an upper spiral disposed alongside said lower spiral; a permeable membrane separating said lower and upper spirals; and, outlet means at the ends of said spirals, whereby substances pumped through said outlet section will pass to the lower spiral where material incapable of passing through said membrane will not pass to the upper spiral increasing the concentration thereof in the lower spiral.

5. An ultra-filtration arrangement as claimed in claim 4 including an upper spiral inlet at the center of said upper spiral to enable said arrangement to be used for dialysis and ultra-filtration.

6. An ultra-filtration arrangement as claimed in claim 4 including outlets from said lower and upper spirals at the outer ends thereof said outlets having restrictive valves governing the outputs therefrom.

References Cited by the Examiner UNiTED STATES PATENTS 2,291,912 8/1942 Meyers 103148 X 2,760,436 8/1956 Von Seggern 103148 X 2,864,507 12/1958 Isreeli 210-321 3,154,021 10/1964 Vick 103--148 3,211,645 10/1965 Ferrari 210321 X FOREIGN PATENTS 582,930 10/1958 Italy.

REUBEN FRIEDMAN, Primary Examiner, F. W. MEDLEY, Assistant Examiner.

Claims

1. A PERISTALTIC PUMP FOR DELIVERING FLUIDS IN EVEN FLOW THROUGH A FLEXIBLE TUBE AT HIGH PRESSURE TO A HIGH PRESSURE CHAMBER COMPRISING IN COMBINATION, AT LEAST THREE SEQUENTIAL LONGITUDINALLY ALIGNED SQUEEZE MEMBERS DESIGNED TO ASSUME EITHER AN OPEN OR SQUEEZE POSITION, PNEUMATIC MEANS CONNECTED TO SAID PUMP TO SIMULTANEOUSLY SEQUENTIALLY AND GRADUALLY SQUEEZE IN PROGRESSION, THE LAST AND FIRST, THE FIRST AND SECOND, THE NEXT TO THE LAST AND LAST, AND AGAIN THE LAST AND FIRST SQUEEZE MEMBERS, THE GRADUAL SQUEEZING BEING IN THE DIRECTION OF DELIVERY, EACH OF SAID SQUEEZE MEMBERS COMPRISING A HOLLOW SOLID FLANGED ELONGATED OUTER JACKET, A HOLLOW RESILIENT FLANGED, TAPERED-WALL INNER JACKET, SAID TAPERING BEING SUCH THAT THE WALL TAPERS COUNTER TO THE FLOW DIRECTION OF THE FLUID BEING PUMPED, SAID TAPERED WALL INNER JACKET BEING DISPOSED WITHIN AND IN ENGAGEMENT WITH SAID OUTER JACKET, THE FLANGES OF SAID INNER AND OUTER JACKETS BEING DISPOSED ALONGSIDE ONE ANOTHER AND FASTENED TOGETHER SO THAT THE INNER AND OUTER JACKETS FORM A CLOSED CHAMBER WHEN INFLATED BY SAID PNEUMATIC MEANS, AN OUTLET SECTION INCLUDING A RIGID TUBE CONNECTED RIGIDLY AT ONE END TO A HIGH PRESSURE CHAMBER AND AT THE OTHER END RIGIDLY CONNECTED TO THE FLANGE OF THE OUTER JACKET DISPOSED ON THE DELIVERY END OF THE LAST OF SAID SQUEEZE MEMBERS, SAID FLEXIBLE TUBE BEING ENCASED IN SAID RIGID TUBE AND THEREIN OUTWARDLY SUPPORTED TO PREVENT ITS BURSTING, AND FEED LINES COUPLING SAID PNEUMATIC MEANS TO EACH OF SAID CHAMBERS.