Description of related art
Controlledly supply the useful reagent such as medicine, accomplished by the whole bag of tricks in medical science and veterinary applications, comprise the implantable delivery device such as inculcating the infiltration supply equipment.Osmotic delivery systems is supplied a useful reagent very reliably on the time (being referred to as the control time) that prolongs.In general, osmotic delivery systems is passed through from an external environment condition absorption fluids, and discharges the useful amount of reagent that control is arranged from supply system.
The representative example of all kinds supply equipment is disclosed in United States Patent (USP) 3,987, and 790,4,865,845,5,059,423,5,112,614,5,137,727,5,213,809,5,234,692,5,234,693,5,308,348,5,413,572,5,540,665,5,728,396,5, in 985,305 and 5,221,278, this paper quotes all these patents for your guidance.All above-mentioned patents generally comprise certain type big envelope (capsule), and it has all walls or wall part (for example, semipermeable membrane), and they make water be passed into big envelope inside selectively.The water absorbing agent (water attracting agent) that water is comprised in the big envelope absorbs, and forms an osmotic pressure in big envelope, then, causes the useful reagent of discharging in the big envelope.Perhaps, water absorbing agent can be the useful reagent that is supplied to patient.Yet, in most of situations, adopt a reagent independently especially, water can be drawn in the big envelope.
When using one independently during penetrating agent, penetrating agent can separate with the useful reagent in the big envelope by a movably actuator such as piston.The structure of big envelope is inflexible basically, and like this, big envelope itself does not expand when penetrating agent suction and expansion.When penetrating agent expanded, it caused movably that actuator moves, and discharges useful reagent by a hole or the exit passageway of big envelope.Useful reagent is discharged by exit passageway with identical volume fraction, and this volume fraction is the penetrating agent of water combination by the semi-permeable wall of big envelope.
In some known implantable delivery device, the hole or the exit passageway of big envelope are often opened, and therefore, allow with reagent and unhinderedly discharge.This causes directly fluid connection between the water around useful reagent and the tissue of patient.Therefore, can cause water to enter into the diffuse in reverse direction of useful reagent storage.A kind of method that reduces the diffuse in reverse direction of water provides a long hole or an exit passageway, and it can be different shape, for example, and straight shape or spiral type.
In other known implantable delivery device, the hole of big envelope or exit passageway be extensile or elastic parts or band covering with one, to reduce the diffuse in reverse direction that water enters into useful reagent storage.In case overcome threshold pressure, extensile or elastic band allows with reagent discharges.Pressure in device is during less than threshold pressure, extensile or elastic parts or be with bore closure.Yet, few or do not have pressure control in the equipment of these types, when equipment is adjusted to variation of temperature and/or inside or external pressure, can form accumulation of pressure.
In also having other known implantable delivery device, hole or exit passageway are made by extensile or elastomeric material at least in part, and it plays and reduces the diffuse in reverse direction that water enters into useful reagent storage.In case reach threshold pressure in this equipment, this extensile or elastic material deforms, and discharges to allow with reagent.When the internal pressure in the equipment during less than threshold pressure, the material in extensible hole is closed.Yet, few or do not have pressure control in the equipment of these types, when equipment is adjusted to variation of temperature and/or inside or external pressure, can form accumulation of pressure.
In general, the supply system of infiltration depends on the flowing of film (also being referred to as semipermeable membrane) that the pore-body fluid traverses flow restriction, expands to drive penetrating agent (osmotic agent), and this drives the supply or the discharging of useful reagent again.In the time course after just inculcating, pore-fluid also can be diffused in the useful reagent (benificial agent) by a useful agent delivery passage (also being referred to as a hole or exit passageway).Such diffusion is unfavorable, because it causes the uncontrolled dilution of useful reagent composition.
Be intended to limit or prevent diffuse in reverse direction and not in the known design of coverage hole or exit passageway that the limitation that has is to require quite long the evolving path to prevent or stops diffuse in reverse direction in the useful agent compartment of direction of flow at those of prior art.By molded intricate detail in plastics, or in metal, process the surface of high tolerance, form slotted hole, the evolving path or exit passageway in these Known designs.These method manufacturing cost height, and occupy sizable volume, cause to inculcate to have a size that increases.
The shortcoming of other of known implantable delivery devices is that these equipment can not compensation temperature and intrinsic pressure variation, and they can cause implantable delivery device to be supplied with high or low speed momently using reagent.Usually, the driving supply system of an infiltration of inculcating, in beating into the patient body before, will be at room temperature (being approximately 20 to 22 ℃) store.In the several hrs after inculcating, system will one after the other reach thermal balance (being approximately 37 ℃) with patient.The rising of this temperature can cause the composition of useful reagent in the infusion device to expand, and this can cause system to be boosted, and is supplied with apace and in short time with reagent (being referred to as starting (start-up) " outburst (burst) " usually).The low a little agent delivery (usually continue less than 1 day to 5 days) of a short time is followed in this outburst usually, at this moment between in the process, osmotic pressure is increased to the degree of the pressure that equals piston friction.When the intrinsic pressure increase of infusion device, the fill rat of useful reagent will rise, and obtain a steady statue up to it.Because the purpose of osmotic delivery systems is the useful reagent with fixed rate supply limiting concentration, so " lagging behind (lag) " in initial " outburst " and the supply thereafter all is unfavorable.
The useful agent delivery system of the osmotic drive of inculcating be that on the other hand it (for example bears external pressure or variations in temperature, rebreather diving, hot bath, or the temperature cycles in the transportation), it can cause the transient peak in the useful agent delivery curve again.
Present design can form enough high pressure in inculcating the infiltration supply equipment, so that one or morely inculcate component failure or evict from.Reducing component failure or evicting from the effort of probability, existing design is provided with groove and/or rib in semipermeable membrane or the hole in the wall of device in chamber wall, if the parts outflow location of equipment, they open wide.Because processing that need be extra to part is so these methods have increased the cost of equipment.
Therefore, an object of the present invention is initial " outburst " reduced to minimum, by comprising useful reagent with a spring-biased valve, the pressure that brings out up to the infiltration of inside enough overcomes the spring force that applies greatly, thus, open valve and allow controlledly release reagent.Of the present invention also have a purpose to be, owing to eliminate initial reagent " outburst ", also can reduce or eliminate the back starting " hysteresis " of useful agent delivery as far as possible.The other result that " hysteresis " started in minimize and the back of this starting " outburst " is that the comparable known agent delivery device of inculcating of system reaches ideal steady-state characteristic significantly soon.
Another object of the present invention is to provide the elimination diffuse in reverse direction with suitable inexpensive manner, does not require sizable or long hole, the evolving path or exit passageway.
Another object of the present invention provides an infiltration supply equipment of inculcating, and it can comprise whole osmotic pressure that can be formed in the device, and need not quite expensive and complicated fluid flow bypass channel.
The describing mode of most preferred embodiment
The present invention relates to a kind of pressure actuated two-way valve and the flow channel of self regulation, be used for inculcating that the useful agent delivery system inner control of osmotic drive is fluidic to flow one.The parts of the flow channel of two-way valve and self regulation are designed to: prevent basically that when the pressure in the useful reagent container is lower than predetermined downforce pore-fluid from passing through therebetween, prevent that when the pressure in the useful reagent container is higher than predetermined upward pressure useful reagent is by therebetween.When this can be lower than predetermined downforce or be higher than predetermined upward pressure at the pressure in the useful reagent container,, fluid flowing passage is achieved by being narrowed down.Under extra extra-lnigh tension, valve can be designed at the bore ends Close All, or it can provide minimal leak path, never surpasses so that maximum fluid flows.Under zero or low-down pressure, valve will fully cut out, or provide the minimal leak path in useful reagent container end, and will be thus that reagent composition and external fluid infiltration is isolated basically, and the elimination external fluid flows into the diffusion in the useful reagent composition.Although these characteristic standard can reach by various discrete parts (for example, relief valve, current limiter, check-valves), the present invention with one single simple and cheaply mechanism make up the characteristic of all requirements.
Although external effect the variation on supply system of expectation such as external pressure or temperature can be conditioned or eliminate is unpractical, but the present invention can be reduced to minimum with their error contribution by requiring to improve total pressure (system still can be assigned and use reagent) significantly under this pressure.Be supplied with by the forced system pumping or with higher pressure and use reagent, in the overall variation of pumping or delivery rate, a decline will be arranged.For example, 0.01 pound/inch
2Pressure increase at 0.10 pound/inch
2The error that the system that normal pressure distributes down causes is far more than 0.10 pound/inch basically
2Pressure increases at 3 pounds/inch
2The system (10% pair 3%) that pressure distributes down.
Fig. 1 illustrates one and has the useful agent delivery system 1 of inculcating osmotic drive of a big envelope 2.Big envelope 2 has the skin of an infiltration, and comprises a useful reagent container 50 and an osmotic agent reservoir 52.Useful agent delivery system 1 also preferably comprises a piston mobile 54, and it is positioned between useful reagent container 50 and the osmotic agent reservoir 52.One fluid permeable membrane 56 is arranged on absorption of fluids end 16 places of useful agent delivery system 1.Fluid permeable membrane 56 can be any suitable film or the combination of various films, and its shape can sufficiently be controlled the Fluid Volume that enters in the big envelope 2.In addition, also answer selective membrane 56 to prevent that the composition in the big envelope 2 from passing through to flow out big envelope.One valve module 10 is arranged on the useful agent delivery end 14 of big envelope.
Big envelope 2 is must intensity enough big, with guarantee can not leak, cracked, fracture or distortion, evict its useful reagent content under the stress that in use stands from and cause, keep permeability simultaneously.Especially, should be designed to bear by the maximum osmotic pressure that penetrating agent produced that rises of the water in the container 52.Big envelope 2 also must be that chemically inertia is upward compatible with biology, that is, it must not react with useful reagent composition and human body.Suitable material generally includes a unresponsive polymer or biocompatible metals or alloy.Polymer comprises the acrylonitrile polymer such as the terpolymer of acrylonitrile-butadiene-styrene (ABS) etc.; Halogenated polymer such as the copolymer of politef, polychlorotrifluoroethylene, tetrafluoroethene and hexafluoropropene; Polyimides; Polysulfones; Merlon; Polyethylene; Polypropylene; Polrvinyl chloride-acrylic copolymer; Merlon-acrylonitrile-butadiene-styrene (ABS); Polystyrene; And, suchlike polymer.The water evaporation transfer rate of passing through composition that is used for forming container can be seen in J.Pharm.Sci. Vol.29,1634-1637 page or leaf (1970); Ind.Eng.Chem.Vol.45,2296-2306 page or leaf (1953); Materials Engineering, Vol.5,38-45 page or leaf (1972); Ann.Book of ASTM Stds., Vol.8.02,208-211 page or leaf and 584-587 page or leaf (1984); And Ind.and Eng.Chem., Vol.49,1933-1936 page or leaf (1957).Above-mentioned polymer can be seen in " general polymer handbook " (the Handbook ofCommon Polymer) by Scott and Roff work that publishes in the Cleveland RubberCo.CRC in the Cleveland city in U.S. Ohio state Press.Be used for metal material of the present invention and comprise rustless steel, titanium, platinum, tantalum, gold and alloy thereof, and gold-plated ferroalloy, platinized ferroalloy, cobalt-chromium alloy, and titanium-nitride rustless steel.Container is made at the titanium alloy more than 60% by titanium or Ti content, and common Ti content is particularly preferred in the apparent especially important use of size greater than 85% alloy.
Osmotic agent reservoir 52 can comprise any suitable penetrating agent, and its example includes but is not limited to non-volatile water-soluble penetrating agent, contacts the expansible osmopolymer in back with water, or both mixing.For example, representational penetrating agent or osmopolymer are disclosed in United States Patent (USP) 5,413, and in 572 and 6,270,787, this paper quotes them for your guidance.Such as the penetrating agent of sodium chloride and examples of suitable lubricants, adhesive with revise agent such as the viscosity of sodium carboxymethyl cellulose or sodium polyacrylate and can be prepared by various forms.For example, as United States Patent (USP) 5,728,386 is described, and the sodium chloride of sheet shape is the agent of rising of preferable water, and this paper quotes above-mentioned patent for your guidance.Penetrating agent should be able to be at 0 and 5200 pound/inch
2Between produce.
The material that is used for fluid permeable membrane 56 is a semipermeable materials, and they are in that to soak the back consistent with the shape of container, and with the sealing of the rigid surface of container formation watertight.In the time of in being placed on fluid environment, semipermeable membrane expands as hydroxide, so, between the match surface of film and container, produce a sealing.The polymeric material that can be made into film requires to change according to pump rate and apparatus structure, and include but is not limited to the cellulosic material of plastification, such as the polymethyl methacrylate of the reinforcement of ethoxy methacrylate (HEMA), and such as the copolymer of the elastomeric material of polyurethane and polyimides, polyester-polyamide, thermoplastic copolymer etc.Other semipermeable compositions is disclosed in United States Patent (USP) 5,413, and in 572 and 6,270,787, this paper quotes them for your guidance.
Movably separator 54 can be that it includes but is not limited to an a slice shape or a piston shape with the water isolated Any shape of agent and useful reagent composition that rises.Movably separator completely cuts off the agent of rising of the water in the chamber 52 with useful reagent composition in the chamber 50, and must the pressure lower seal in the big envelope 2 move.Movably separator 54 is preferably made by such material, that is, it is lower and will be out of shape the inside that adapts to big envelope than the hardness of big envelope 2, so that the compression seal with the fluid tight of big envelope 2 to be provided.The material of making separator movably or piston is preferably infiltrative elastomeric material, and include but is not limited to polypropylene, rubber, silicone rubber, butyl rubber etc. such as EPDM, fluoroelastomer, perfluorinated elastomers, and such as the thermoplastic elastomer (TPE) of the polrvinyl chloride of plastification, polyurethane, Santoprene , C-Flex TPE, styrene-ethylene-butylene-styrene copolymer (Consolidated Polymer Technologies Inc.) etc.Movably separator can be the design of compression-loaded.
The drug delivery device of inculcating of the present invention is used for supplying various activators.These activators include but is not limited to activatory contract ammonia root and protein, gene and wip gene, other gene therapeutic agents on the pharmacology, and other small-molecule substance.Bunching ammonia root can include but is not limited to growth hormone, the growth hormone homologue, somatomedin-C, the hormone that stimulates gonad to discharge, follicle stimulating hormone, lutropin, LHRH, such as leuprolide, the LHRH homologue of nafarelin and goserelin, LHRH shrinkage rib and antagonist, somatotropin releasing factor, calcitonin, colchicine, such as the short gonad of chorion, oxtocin, octreotide, growth hormone adds aminoacid, vaspressin, thyroliberin, epidermal growth factor, prolactin antagonist, Somat, growth hormone adds protein, the 1-24 thyroliberin, lypressin, polypeptide such as thyrotrophin-releasing hormone, throid stimulates hormone, secretin, pancreozymin, enkephalin, glucagon, inner secretion and the endrocrine agent that distributes by means of blood flow etc.Other reagent that can supply comprises α
1Anti-insulin, Factor IX, factors IX, and other coagulation factor, insulin and other the ammonia root hormone that contracts, adrenal cortex stimulates hormone, thyrotropin, and other pituitary hormone, interferon includes but is not limited to α, β and γ erythropoietin, such as GCSF, the somatomedin of GMCSF, the somatomedin 1 of insulin-like, the former activation factor of tissue plasminogen, CD4, Ddavp, the IL-1r antagonist, the tumor necrosis factor acceptor, the tumor suppression body protein, cytotoxic protein and reconstitution cell antibody and antibody fragment etc.
Mentioned reagent is effectively for handling the multiple state of an illness, and these situations include, but is not limited to hemophilia and other hematologic disease, retardation of growth, diabetes, leukemia, hepatitis, renal failure, HIV infects disease, genetic diseases such as cerbrosidase deficiency disease and adenosine deaminase deficiency, hypertension, septic shock, autoimmune disease such as multiple sclerosis, exophthalmic goiter (Graves' disease), systemic lupus erythematosus and rheumatic arthritis, shock and marasmus, cystic fibrosis, lactose intolerance, Crohn disease (Crohn disease), intestinal inflammation, gastrointestinal and other cancer.
Activator can be anhydrous solution aqueous solution, suspension are arranged or with pharmacology on acceptable excipient or vectorial association, like this, form flowable composition so that they can be long-term stored on the frame or refrigerator in and be stored in one and inculcate in the supply system.All compositions can comprise receptible vehicle and additional inert fraction on the pharmacology.Activator can take various forms, for example, and uncharged molecule, receptible salt on the component of molecular complex or the pharmacology.Moreover, can use the simple derivatives (for example prodrug, ethers, esters, amide class etc.) of reagent, their PH by health, enzyme etc. are aquation easily.
Valve body 30 and 32 is preferably made by titanium, steel and their alloy, thermoplastic, and thermoplastic includes polyether-ketone (PEEK) or liquid crystal polymer (LCP) etc.More preferably be that valve body 30 and 32 is made by liquid crystal polymer.
Spring 24 is preferably made by spring steel, comprises rustless steel or beryllium/copper, or injection molding polymer or plastics.Spring material should provide yardstick, has the wire thickness that can make and be inserted in the valve simultaneously.More preferably, producing of spring 24 should be: made by rustless steel for the filament spring, made by suitable plastic for thicker silk spring.The profile of spring 24 can be circular, square or any other suitable shape.Spring 24 provides from the fluid path of container 50 by upper port 22.
Bar 46 and lead 48 can be by making with valve body 30 and 32 identical materials, or by the elastomeric material such as fluoroelastomer, Perfluoroelastomer, make such as the thermoplastic elastomer (TPE) of C-Flex or Santoprene , duroplasts etc.Bar 46 and lead 48 are preferably by thermoplastic elastomer (TPE), or Perfluoroelastomer, or duroplasts is made.
In operation, the outside effusive fluid from big envelope 2 enters in the big envelope by film 56.Then, some fluid is absorbed by the penetrating agent in the container 52, thus, causes penetrating agent to expand.Along with penetrating agent expands, the volume of its increase causes piston 54 to be pushed on to be accommodated in the useful reagent in the useful reagent container 50, distributing by valve module 10, and enters in the patient body.Yet when the pressure in the big envelope 2 during greater than predetermined downforce, useful reagent just sends by valve module 10.Describe the mechanism of valve module 10 below in detail with reference to Fig. 1-5.
As illustrated in fig. 1 and 2, valve module 10 comprises a valve body 12, and it contains the fluid chamber 60 and 70 of a plurality of interconnection.Valve module should have the height dimension greater than diameter dimension.In other words, the height of valve module should be greater than 1/1 to the ratio of width.The height of valve module should be less than 1/5 to the ratio of width.Preferably, the height of valve module to the ratio of width between 1/1 and 1/2.Valve module preferably has the diameter of about 1mm to 10mm, more preferably is about 3mm to 6mm.Valve module preferably has the height of about 5mm to 10mm.
Valve body 12 preferably comprises two identical halves 30 and 32.Valve module 10 also comprises a lower port 20 and a upper port 22.One bottom fluid chamber 60 is positioned near the lower port 20, and is communicated with lower port 20 fluids.One upper fluid, chamber 70 is positioned between upper port 22 and the lower fluid chamber 60, and is communicated with its fluid.
Lower fluid chamber 60 comprises that a first surface 62 and with a frusto-conical shape has columniform second surface 64.The diameter of the bottom part of first surface 62 is less than the diameter of lower port 20.The diameter of the top part of first surface 62 diameter with second surface 64 basically is identical.Lower fluid chamber 60 comprises that also one is substantially perpendicular to the 3rd surface 66 of second surface 64.
One passage 74 that is formed on the 3rd surface 66 and upper fluid, chamber 70 intersections is arranged between the upper and lower fluid chamber.Basically less than the diameter of upper fluid, chamber 70, therefore, top surface 72 (also being substantially perpendicular to 64) is arranged on therebetween the diameter of upper port 22.
As shown in Figure 2, valve module 10 comprises a closure member 40 movably, and it has a cylindrical seal 44 and and is attached to frustum 42 on an elongated cylindrical bar 46 (more clearly being shown among Fig. 2 b) and the lead 48.The diameter of bar 46 is slightly less than spring 24.The diameter of lead 48 should be slightly less than the diameter of upper port 22.Movable closing member 40 also comprises a flat basically upper surface 90.Closure member 40 and cylindrical bar 46 can be processed into a single part, preferably by molded or they can process individually, and attached together with any known method.In addition, bar 46 can be processed into an end of thread, and it is configured to and is arranged on the threaded openings coupling on the upper surface 90 of closure member 40.
Movably closure member 40 can move to the uppermost position in fig-ure on contiguous the 3rd surface 66 basically from the upper/lower positions of a contiguous basically first surface 62.When closure member was positioned at upper/lower positions, the shape of the frustum of a cone 42 of closure member 40 was mated with first surface 62 basically.In addition, when closure member was positioned at uppermost position in fig-ure, the shape of the upper surface 90 of closure member 40 also covered the 3rd surface 66 of lower fluid chamber 60 basically.When closure member 40 movably is positioned at above-mentioned arbitrary position, hindered basically from useful reagent container 50 effusive useful reagent streams by valve module 12.
Spring 24 is arranged on around the cylindrical bar 46, and between top surface 72 and upper surface 90.Spring 24 is preferably a spiral compression spring, and is shown among Fig. 1.However, it is to be understood that: can adopt any other suitable spring to replace spiral compression spring.
Zero or (for example, 0.5 to 10 pound/inch of low pressure
2) under, storing or initial pumping begins in the process like that such as being expected, spring 24 remains on a certain position with closure member 40, flows along the either direction of valve module 12 to stop fluid basically.Cylindrical seal 44 prevents that fluid from traversing flowing of lower port 20, like this, is included in any useful reagent in the useful reagent container 50 and is presented between the pore-fluid (in case inculcating) at upper port 22 places, does not have the fluid connection basically.In addition, as shown in Figure 2, movably closure member 40 is designed to move through certain predetermined displacement, and still remains on the sealing at lower port 20 places.Because the height of cylindrical seal 44 is greater than the height of lower port 20, so, this situation can take place.The reagent that this feature makes valve module 10 can be included in the increase that causes because of thermal expansion when inculcating becomes partial volume, and does not have the initial burst as being taken place in many devices.
Valve 10 is maintained in its closed position (shown in Fig. 2 and 4) or the needed pressure of open position (as shown in Figure 3), for example, depend on the amount of space that the viscosity of useful reagent composition, useful reagent composition occupy in valve 10 from the spring constant and/or the spring 24 of the desired speed of system supply, spring 24.
From low pressure to highly compressed pound/inch
2Scope (opening to valve from valve closes) need be very narrow, but in any case can be at about 0.1 to 2000 pound/inch
2Scope in.Preferably at about 0.5 to 100 pound/inch
2Scope in.
By spiral compression spring 24 being positioned at the top of the cylindrical bar 46 of movable closing member 40, process valve module 10.Thereafter, valve module 10 is limited between two body halves 30 and 32, the first surface 62 and the lower port 20 that frustum of a cone 42 and cylindrical seal 44 are oriented be engaged in lower fluid chamber 60 respectively.Synthetic assembly will cause spring 24 to be in the loading of compression, and sealing is resisted against first surface 62 at lower fluid chamber 60 places to force frustum of a cone 42.Therefore, valve module 10 is closed fluid flow at lower port 20 places usually.Any method of body halves 30 and 32 in can several different methods known in the art is sealed.For example, use binding agent, ultrasonic bonding, or machinery cooperates.
Fig. 3 illustrates in case the fluid pressure at lower port 20 places surpasses (for example, about 5 pounds/inch of minima
2) time valve operation, described minima can be the situation of normal running.In this case, movably closure member 40 will make progress vertically towards upper port 22 displacements, and 20 places form an opening in lower port, and allow with reagent from reagent container 50 pumpings by lower port 20, then, one after the other, flow out upper port 22 at last by lower fluid chamber 60 and 70.The sectional area of opening, Xiang Guan fluid flow is proportional to by fluid and resists movably closure member 40 applied pressures thus, begins near in certain predetermined maximum value up to pressure.In this case, when the upper surface 90 of closure member 40 near lower fluid chamber 60 the 3rd surperficial 66 the time valve events reverse.
Spring 24 forms a spiral type fluid flow path by upper fluid, chamber 70.Upwards done the time spent when closure member 40 movably by flow agents, spring 24 by compression.Therefore, when the fluid pressure in useful reagent container 50 and the chamber 60 increased, lower port 20 was more fully opened, and simultaneously, fluid flow path little by little narrows down, and therefore becoming is tied more.Proper flow will cause balance between the relative power of spring and fluid pressure, and low fluid flow is usually with the prevention of spring 24 by compression fully, cause lower port 20 quilts movably closure member 40 close.On the other hand, high fluid flow will be subjected to the obstruction roughly of the upper surface of closure member 40 movably usually and close opening 74 basically.Being compressed between lower fluid chamber 60 and the upper port 22 of spring 24 reduces flow path.
Fig. 4 illustrates when arriving (for example, about 20 pounds/inch of maximum pressures
2) time the situation of valve.Movably closure member 40 is driven to the uppermost position in fig-ure among Fig. 4, forces displaceable member to be resisted against the 3rd surface 66 of lower fluid chamber 60.The motion of this restriction movable closing member 40, and close lower fluid chamber 60 and be communicated with fluid between the upper fluid, chamber 70.Perhaps, in a preferred embodiment, by the little fluid bypass passageway around the movable closing member 40, with the fluid flow restriction around the movable closing member 40 on a certain predetermined minimum.When pressure discharged, fluid path increased sectional area at upper surface 66 places, thus, allowed to increase fluidic flowing once more.Like this, control fluid flow continuously, with compensatory pressure and variation of temperature, otherwise this variation can cause not optimal performance.
Above-mentioned detailed description relates to special embodiment of the present invention.Yet, from above-mentioned open, obviously can easily realize material, process technology and the alternate embodiment of a broad scope.Another embodiment of the present invention comprises an independent little fluid bypass passageway, and it can form by following dual mode: the aperture by movable closing member 40 or be formed on an intramarginal groove of movable closing member 40.
For example, Fig. 5 illustrates another preferred embodiment of the present invention, and wherein, valve module 80 can be processed into a silicon microstructure (silicon microstructure) or use molded thermoplastic.As shown in Figure 5, valve module 80 comprises that one has the valve body 81 of the single chamber of integrally formed cantilever spring arm 82, to replace above-mentioned compression spring.Cantilever spring arm can be made by metal (such as the above-mentioned metal that is used for valve body 30 and 32) or thermoplastic.In addition, movable closing member 86 is the spheroid form, and is attached on the free end of cantilever spring arm 82.Movable closing member 86 can be made by metal or metal alloy (such as the above-mentioned metal that is used for valve body 30 and 32), thermoplastic or elastomer.The upper port of this embodiment needn't have identical diameter with lower port, if when pressure be below or above one be scheduled to pressure the time movable closing member 86 close the vertical component of upper port or lower port.Yet other shape also can be used for closure member 86.One potential benefit is that this embodiment has the structure of one, rather than an assembly and discrete parts.Also having another benefit is its especially little overall volume.
In addition, although the application of an osmotic drive agent delivery system has specifically been introduced in above description, the present invention can be applicable to the fluid feed system of any pressurization obviously.
The embodiment of above-mentioned demonstration is intended to illustrate various aspects of the present invention, rather than restriction the present invention.Therefore, the present invention can have many variations and detailed embodiment, and they can be derived out from the description that this paper comprised by those skilled in the art.Variation that all are such and remodeling are considered to fall within by in the defined scope and spirit of the present invention of appended claims.