Abstract: An aspiration control system includes a motor and vacuum pump which are controlled by a system controller, in accordance with input commands to provide a precise, continuously variable vacuum or negative pressure within a vacuum chamber and surgical handpiece. The resulting vacuum is proportional to the control signal sent from the system controller to the motor. A transducer samples the vacuum output and produces a signal fed system controller. The signal is compared with a variable input signal set by a potentiometer or other signal source activated by the input commands so that the transducer signal tracks the voltage source signal. Therefore, the vacuum output of the vacuum pump and motor relates directly and predictably to the input commands. In one embodiment the motor is a brushless DC motor.

Abstract: The invention provides an irrigation and aspiration device for use in laparascopic and other types of surgery. When connected to existing irrigation and suction sources, the device provides fingertip control of the fluid connections between the sources and a tube. The device comprises a valve housing with two valve assemblies inside, mounted and configured to take advantage of the static pressure supplied by the sources for increasing seal integrity of the valves. The internal chambers of the valve housing are also configured such that when one valve is open, the pressure differential across the other valve is increased, further increasing its seal integrity.

Abstract: A medical-surgical tube having a major lumen defined by an inner periphery of a wall of the tube, an injection lumen within the wall of the tube, and at least one one-way valve in the wall. The valve allows fluid to flow from the injection lumen through an outer or inner periphery of the wall of the tube and prevents return of the fluid back into the injection lumen. The tube can include a plurality of spaced-apart valves. The valve can be a piercing in the wall of the tube which is defined by opposed surfaces resiliently biased against each other and extending from the injection lumen to the outer or inner periphery of the wall of the tube.

Abstract: An intra-abdominal organ manipulator, irrigator and/or aspirator is described which includes a tubular probe member with distal and proximal ends and a through lumen extending the length thereof. A balloon is affixed to the distal end to aid in manipulating organs or parts thereof within the abdominal cavity when inflated through an auxiliary lumen in the probe. A handle attached to the proximal end of the probe has a pair of trumpet valves which allow the user to connect a vacuum source or irrigation fluid source to the through lumen.

Abstract: A releasable coupling connector apparatus for catheter applications is provided wherein the connector is partially filled wtih anti-infective solution during manufacture and capped so that a patient or medical technician does not have the task of opening the fluid pathway and introducing the anti-infective solution at point of use into the connector apparatus. The connector apparatus being partially filled with anti-infective solution and capped during manufacture is further sterilized by Gamma radiation in order to eliminate any organism resistant to the anti-infective solution. The releasable coupling connector apparatus provides the first practical double seal connector means wherein a double seal connector defining dual sterilant liquid containing chambers for use with catheter applications and particularly with CAPD whereby sterilization is assuredly and easily achieved by an impaired, unskilled patient even under adverse conditions.

Abstract: An improvement to a flow control system is disclosed which comprises a transducer apparatus having dampening means to prevent or reduce the destructive effect of water hammers in such fluid control systems. This is especially useful in surgical irrigation and aspiration systems. The dampening means functions by diverting the transient fluid waves away from the delicate pressure-sensing means until a portion of the kinetic energy contained therein is dispersed.

Abstract: An irrigation system for irrigating and pressurizing a body cavity during an endoscopic procedure, such as during arthroscopy, includes a source of irrigation liquid, a pneumatically driven pump for pumping irrigation liquid from the source into the body cavity. The pump develops pulsatile flow and its operation is controlled by a pressure regulator that regulates the pressure of air applied to the pump. The system enables disablement of the pumping function of the pump while permitting gravity flow of irrigation liquid to the body cavity. The pump and associated tubing is inexpensive and adapted for one-time, disposable use.

Abstract: A check valve assembly for use in medical devices having a single valve disc therein to allow a medical fluid to be drawn from a bulk container through the inlet opening and secondary opening of the valve assembly and into a syringe and then subsequently dispensing the fluid from the syringe through the secondary opening and outlet opening of the valve assembly and into a second container or to the patient. Alternately, the valve assembly may be used with a squeeze bulb of an aspiration device such that as the bulb is squeezed, the air in the bulb passes from the secondary opening to the outlet opening of the valve assembly and then, as the bulb is released, the negative pressure from the bulb is transmitted through the secondary opening and inlet opening of the valve assembly to the aspiration device to draw fluids from the patient and into the aspiration device.

Abstract: Collapse of the cornea into the cavity formed when material such as the lens is removed from an eye in the irrigation-aspiration method is minimized by incorporating a pressure responsive, variable flow resistance element in the aspiration line of the irrigation-aspiration apparatus. A preferred pressure responsive, variable resistance element is a length of thin walled tubing which is easily collapsed to smaller flow path area in response to increasing negative pressure in the aspiration line.

Abstract: A system for controlling the irrigation and aspiration functions in flow lines cooperative with a surgical control console employs a reusable receiver within which a disposable cassette is insertable. The cassette includes lines which must be sterile for each user, but cooperates with elements in the receiver to which it is detachably engaged. Slider bars within the receiver are arranged to transmit clamping forces against interior flexible lines such that shortened and simplified flow paths are used.

Abstract: A peritoneal dialysis system is disclosed for administering substantially sterile dialysate to the peritoneal cavity of a patient. The system includes a dialyzer for passing a primary solution and a secondary solution therethrough to enabale removal of waste products from the primary solution to the secondary solution, and a primary circuit for selectively circulating a primary solution through the dialyzer. Connecting conduits or tubing is provided for selectively carrying primary solution from the primary circuit to the peritoneal cavity of the patient and for selectively withdrawing at least some of the solution from the peritoneal cavity back into the primary circuit. A pump is disposed in the primary circuit for causing primary solution to circulate in the primary circuit independently of transfer of primary solution between the primary circuit and the peritoneal cavity of the patient.

Abstract: A tool that lowers the temperature of the heart during surgery or other times when blood flow to the heart is cut off. The tool has the appearance of a spoon and includes an elongate handle part and a heart-cradling part at the end of the handle. A first passageway formed in the handle delivers a continuous flow of cold liquid to the rim of the heart-cradling part of the tool and the cold liquid flows continuously out of perforations formed about the rim of that part of the tool for as long as refrigeration is needed.

Abstract: A valved catheter is disclosed having an elongated, flexible tubular element defining a lumen extending along an axis substantially parallel to the central axis of the tubular element, and a bidirectional check valve assembly near its distal end which controls fluid flow in the tubular element. The valve assembly includes an aspiration valve offset from the tip of the distal end and an infusion valve formed at the tip of the distal end. The aspiration valve is generally defined by port(s) in the tubular element and a sleeve within the element underlying the ports, where the sleeve normally closes the ports. The aspiration valve permits fluid flow from the bloodstream into the element when the static fluid pressure inside the distal end is lower than the static fluid pressure outside the aspiration valve by an amount sufficient to displace the sleeve to allow fluid flow through the ports. The infusion valve includes a throat formed in the distal end which tapers down to a mouth formed by jaws at the tip.

Abstract: Collapse of the cornea into the cavity formed when material such as the lens is removed from an eye in the irrigation-aspiration method is minimized by incorporating a pressure responsive, variable flow resistance element in the aspiration line of the irrigation-aspiration apparatus. A preferred pressure responsive, variable resistance element is a length of thin walled tubing which is easily collapsed to smaller flow path area in response to increasing negative pressure in the aspiration line.

Abstract: There is provided a medical fluid cassette made of thermoformed plastic material which cooperates with a medical control unit having retaining structure cooperable with the cassette to assist in controlling the flow of fluid through tubing associated with the cassette.

Abstract: An apparatus for selectively providing irrigation or evacuation to a patient during surgery which includes valve arrangements to prevent reflux of fluid and the drawing of irrigation fluid from a reservoir in the event the patient line becomes blocked.

Abstract: Disclosed is a pneumatically-driven volume controlled bellows pump apparatus for oscillating liquid into a localized area of the human body, preferably methyl-tertiary butyl ether or another solvent, into the gallbladder. The pump includes a fluid reservoir in the form of an inverted syringe attached via a stopcock to the bellows. The bellows is attached via a second stopcock to a catheter also attached to a priming syringe. An inlet pinch valve is disposed between the bellows and the fluid reservoir and an outlet pinch valve between the bellows and the fluid receiver.To use the pump, a pigtail catheter with outlets in the pigtail is inserted into the desired area of the body, preferably a receptacle such as the gallbladder, to introduce a selected volume of liquid for gallstone dissolution. Liquid is infused into the receptacle by decompression of the bellows with the inlet but not the outlet valve open and then by compression of the bellows with the outlet but not the inlet valve open.

Abstract: A low-pressure, low blood trauma hemodynamic support system is disclosed. The system may operate as a relatively static-volume, gravity-fed, extracorporeal blood circulation and oxygenation system that consists essentially of (1) a membrane-type blood oxygenator, (2) a non-occlusive roller pump, and (3) connecting tubes. The tubes connect the system components to create a compact system capable of supporting a patient in circulatory dysfunction who is to undergo a transplant operation, and is awaiting a donor organ.

Abstract: An angioscope has irrigation system with at least two presettable irrigant flow rates. A footswitch under manual control is operatively connected to a roller pump for switching from a high first flow rate to a low second flow rate. Upon an initial filling of a blood vessel under observation with clear irrigant at the high flow rate, the operator switches to the low flow rate. The rate of fluid flow may alternatively be continuously variable under manual control.

Abstract: In a device for the recovery of a tissue sample, tissue fluid or similar, which is detached and/or aspirated by a surgical instrument, tubing is provided between the surgical instrument and a collecting device. A vacuum-producing apparatus is assigned to the tubing. In this case the tubing (5) is to be connected to a transmission head (4), which rests with a ring seal (15) on the collecting apparatus (7).

Abstract: An apparatus for selectively providing irrigation or evacuation to a patient during surgery which includes valve arrangements to prevent reflux of fluid and the drawing of irrigation fluid from a reservoir in the event the patient line becomes blocked.

Abstract: A pump apparatus such as a stomach pump or the like having a variable volume pumping chamber in the form of a resiliently flexible bulb with a one way flow check valve disposed within the bulb to preclude backflow therefrom, and a second check valve downstream of the resilient bulb, preferably within a reservoir to preclude backflow from the reservoir to the pumping chamber and to contain pumped matter within the reservoir.

Abstract: A method and apparatus to evaluate the performance of an implanted medication delivery device such as pumps and ports is described. In the case of a pump, the system measures ambient pressure and obtains two pressure measurements from the implanted device. One of these measurements is device reservoir pressure and the other is based on a disturbance pulse injected into the system at a point downstream of the reservoir. Based on those measurements and input calibration data, an expected flow rate is determined. The expected flow rate together with device refill data is in turn used to determine a normalized flow rate for the in-vivo device. Determinations are then made as to the performance of the reservoir, its pump and the condition of the outlet catheter without explant of the device. In the case of a port, the system measures the catheter resistance based on decay time of a disturbance pulse.

Abstract: A closed system for percutaneous irrigation and drainage of cavities containing abscesses, sterile fluid collections or hematomas includes an irrigant reservoir; an irrigation tube connects the reservoir to a first port of a first three-ported connector adapted to fluidically connect two of the three ports at a time. A syringe is connected to the second port of the first connector, and an extension tube connects the third port of the first connector to a first port of a second three-ported connector adapted to fluidically connect two of the three ports at a time. The distal end of a drainage catheter is adapted to be placed in the cavity. The proximal end of the catheter is connected to the second port of the second connector. A drainage tube is connected to the third port of the second connector to a means for collecting fluids draining from the cavity.

Abstract: A sterilizable medical/dental syringe having a handle with a nozzle at one end is provided with means for releasably coupling the other end of the handle to a flexible supply hoses providing compressible gases and/or noncompressible liquids. When disconnected from the flexible hose supply line, automatic sealing valves prevent the contents of the supply line form escaping. A readily repairable flow control valve for the nozzle is also disclosed.

Abstract: An irrigation system for arthroscopy of a joint includes a high pressure bleed valve assembly and a monitor check valve assembly to control fluid communication to the joint via suitable tubing for the purposes of directing fluid inflow, joint fluid pressure monitoring, and to assist with connection of the tubing for an arthroscope and cannula inserted into the joint. The high pressure bleed valve assembly is pressure responsive to direct fluid to the joint via alternative paths.

Abstract: A fluid flow control apparatus specially adapted for use with an ultrasonic surgical tool which provides for irrigation of a surgical site and for aspirating fluid from the site comprises a source of irrigation fluid, comprises an irrigation fluid conduit for conducting the irrigation fluid to a surgical site, an aspiration fluid conduit for conducting fluid away from the surgical site, a suction pump connected to the aspiration fluid conduit for aspirating fluid from the surgical site, a pressure-sensitive control system for removing the source of suction from the aspiration conduit when a predetermined value of suction is exceeded, and a valve for controllably admitting irrigation fluid into the aspiration fluid conduit. A check valve in the irrigation conduit prevents a reverse surge when the irrigation fluid is admitted to the aspiration conduit.

Abstract: An apparatus for maintaining intra-ocular pressure while simultaneously removing and replacing fluid in a patient's eye, for example, during cataract surgery, includes a pair of cooperating expansible bodies connected via fluid conduits to the eye. The expansible bodies may be piston/cylinder assemblies such as syringes. The plungers and/or the barrels of the syringes are mechanically linked together for equal and opposite operation of the two syringes, whereby input and output flow are precisely equal. The syringes are preferably placed back to back along a common axis. The barrels are rigidly spaced and a drive means is applied between the spaced barrels and the endwise-connected plungers.

Abstract: A set-up kit for surgical irrigation/aspiration equipment includes an irrigation tube and a suction aspiration tube for operative connection to an irrigation/aspiration machine. The aspiration tube is releasably connected to a hexagonally-shaped nozzle means on the machined fitting, which fitting is in turn releasably connected to a receptacle containing an air passageway on the irrigation/aspiration machine. This arrangement serves to isolate the aspiration tube from the machine. To further isolate, a disposable hydrophobic filter is placed in the branch line between the machined fitting and the aspiration tube.

Abstract: A fluid supply system for gas and sterile liquids consisting of a disposable sterile cartridge that is connected to gas and liquid sources and a common exhaust. The cartridge cooperates with a rotating bearing assembly which pumps the liquid through the system without ever contacting the liquid. The gas sources are provided with means for supplying the gas under pressure to the cartridge. A suitable control selects either the gas or liquid source and a pair of gauges monitor the flow rates of the fluids.

Abstract: A device for cleansing the colon includes an elastic housing with an oval-shaped end and provided with an aspiration channel and a discharge channel isolated from each other, each channel having its own outlet port in the end of the housing. An endoscope is built into the aspiration channel and is provided with a transparent balloon on its working portion, while the discharge channel accommodates an open-end capillary tube whose open end is brought outwards through the end of the housing, the other end of the tube being connected to a pressure measurement instrument.

Abstract: A novel finger-actuated bypass holder apparatus for ocular cortex fluid aspiration and refluxing and the like, in which the vacuum or suction is normally bypassed through an aperture in the holder which the surgeon may, at will, occlude or open with the finger to enable instantaneous application or removal of vacuum and fine control of aspiration, and with a forward proximal squeezable reflux chamber also finger-actuable at the operating site.

Abstract: A blood filtering system includes a check valve for preventing fluid back-flow, coupled between a peristaltic pump and a pressure equalizer, the valve including a tubular container having an inlet and an outlet, two elongated plastic films in the container extending from the inlet facing each other, joined at their peripheries, with a hole in an end of one film proximate the container outlet. Fluid may flow from the inlet through the films to the outlet; but, back-flow is prevented by collapse of the films.

Abstract: A gravity supplied irrigator for colon cleansing has an open ended nozzle with the inner end tapered to accommodate a removable rounded nose obturator extending from the inner end with the body of the round nose obturator bearing against the inner surface of the inner end. A gravity actuated fluid supply to the irrigator is provided by a conduit leading into the nozzle intermediate of its ends and the obturator is removable through the nozzle in order for the fluid supply to enter the irrigator. The conduit supply is preferably offset in relation to the longitudinal axis of the nozzle to provide a swirling action to the entering fluid. The nozzle has an outwardly extending circumferential flange intermediate of the inner end and the conduit, which flange limits the insertion of the irrigator. A conduit attached to the other end of the nozzle has variable control means thereon to control the pressure of fluid in the nozzle and its rate of discharge from said nozzle.

Abstract: A fluid flow control apparatus specially adapted for use with an ultrasonic surgical tool which provides for irrigation of a surgical site and for aspirating fluid from the site comprises a source of irrigation fluid, comprises an irrigation fluid conduit or conducting the irrigation fluid to a surgical site, an aspiration fluid conduit for conducting fluid away from the surgical site, a suction pump connected to the aspiration fluid conduit for aspirating fluid from the surgical site, a pressure-sensitive control system for removing the source of suction from the aspiration conduit when a predetermined value of suction is exceeded, and a valve for controllably admitting irrigation fluid into the aspiration fluid conduit. A check valve in the irrigation conduit prevents a reverse surge when the irrigation fluid is admitted to the aspiration conduit.

Abstract: A tubing set, the major portions of which are defined from a trilumen section of tubing, comprises three lines including an inflow line, an outflow line and a pressure sensing line. The inflow line includes a header portion engageable about the rollers of a peristaltic pump, a delivery tube mounting a male luer fitting for engagement with a patient cannula, and a pair of clampable supply tubes with bag spikes for communication with saline bags. The pressure sensing line includes a pressure transmitting elongate tubular diaphragm mounted within a fluid chamber directly adjacent the patient end of the line. The pressure transmitting diaphragm communicates with an elongate dry or air tube which, at the remote end, communicates with an appropriate pump-mounted pressure transducer or the like.

Abstract: A drug dosage calculation system includes a hand held, battery operated computing device for use by nurses and other clinical personnel to make calculations pertaining to the drug administration rate and the corresponding flow rate settings of IV systems that are used for intravenous administration of fluids to a patient. Flow rate setting, drug dose rate, drug amount and the amount of IV solution into which the drug is diluted are the primary variables used in such calculations. A keyboard is used to supply data to a computation device that computes the unknown quantity. A display device displays the data input to the computer and also displays data calculated for the unknown variable.

Abstract: A microsurgical irrigation/aspiration system is provided, including a controller having a pump roller head, actuators for occluding tubing, a suction sensor, and apparatus for mounting a pump cassette. The system cassette is suitable for mounting on the controller and has an opening with a pump tubing segment passing along an arcuate wall of the opening. When the cassette is mounted on the console, the roller head is engaged in the cassette opening and compresses the pump tubing segment against the arcuate wall. An infusion line passes through the cassette and is occludable by one of the actuators, and a vent line connected to the pump tubing segment is occludable by a second actuator. A suction sensing port on the cassette couples with the suction sensor in the controller.

Abstract: The invention concerns an apparatus for controlled irrigation of the natural cavities and tubes of the human body. It is characterized in that it includes correcting means for equalizing the measuring signal which represents the pressure and which is emitted by a pressure gauge (10) according to the pressure losses and according to the difference of height between the area of measurement of the pressure and the intervention area which corresponds to an organ (2). These correcting means includea correcting circuit (14B) adapted to effect a correction according to said difference of heightand a correcting circuit (14C) adapted to take into account the pressure loss, namely the flow rate of the fluid injected through the inner duct (6) of the endoscope (1) and the cross section of this duct.

Abstract: A plug is provided within a port in a flexible container. Extending from the port is a piece of flexible tubing which is used to connect with other tubing in a fluid system. Fluid is dispensed from the flexible container by grasping the end of the plug extending into the flexible container. The plug is then pulled into the interior of the container so that the opposite end of the plug which seals the flexible tubing extending from the port is unseated. The flexible tubing extending from the port is now open to the flow of fluid from the flexible container.

Abstract: A linking mechanism for irrigation/aspiration machines which includes a coupling member having a plug that is inserted into an opening in a receptacle on the face of the I/A machine. The plug projection is sealed in air tight relation to the wall surrounding the opening and an auxiliary prong(s) prevent rotation of the plug as well as lock the plug in the receptacle. The receptacle includes an arming switch activated responsive to proper seating of the plug in the receptacle to arm the peristaltic pump that is subsequently operated by a foot switch to generate a vacuum in the aspirant line.

Abstract: A cassette is structurally adapted to receive at least a portion of an irrigation manifold and an aspiration manifold, so that when the cassette is firmly secured to a cassette mechanism on an emulsifier/aspirator unit: (1) the flow to irrigation solution through the irrigation manifold is regulated; (2) the flow of aspirated fluid and tissue from the surgical site is regulated; (3) the vacuum control system (VCS) within the unit is applied to the aspiration manifold. The cassette defines, at its leading edge, an irrigation opening, an aspiration pump opening, and a vacuum control system opening. The cassette housing defines an irrigation boss having a flat leading edge surface in register with the irrigation opening, while an aspiration boss is located in register with the aspiration pump opening. A cassette mechanism is located on the emulsifier/aspirator unit and is structurally adapted to receive the cassette to complete the fluidic connection upon insertion of the cassette.

Abstract: An ophthalmic aspirator-irrigator system for use during cataract surgery is disclosed. The system frees both hands of the surgeon for the surgical tasks and leaves the automatic operation of the system to a single control input operated by a foot pedal. The pedal controls both the aspiration and ejection functions as well as their respective speeds. The opthalmic aspirator-irrigator system essentially comprises a hand-held device, a control box operable by the foot pedal and a power cord connecting the device with the box. A source of fluid is connected via a tube to the device to effect the irrigation function. The control box includes a power source and a circuit coupled to the source and via the cord to the device. Preferably, the circuit includes a bridge output network controlled by a linear motion slide type potentiometer controlled by the foot pedal.

Abstract: The invention is directed to an improved system for mounting a drop sensor onto a drip chamber having laterally projecting wing-like or flange-like extensions. A pair of mounting members, one fixed, one laterally movable, are provided on the drop sensor housing. The mounting members have inclined guiding surfaces which cradle both ends of the lateral extensions on the drip chamber during the initial stages of mounting the drop sensor to the drip chamber and guide drop sensor movement with respect to the drip chamber to its final mounted position thereon. The mounting system is particularly adapted to dedicated IV set and drop sensor combinations.

Abstract: This invention provides an automatic irrigation and evacuation device for use in laparoscopic procedures and surgery. The device comprises a means for directing a flow of liquid and, alternatively, applying a vacuum, through a single line. In the preferred embodiment of this invention, the device provides two different positive controls for alternatively directing a flow of sterile irrigating solution and applying a vacuum through a single line passed through a laparoscope housing into a patient. The two different controls prevent confusion by the operator of the device, increasing the safety of the patient during medical procedures. The invention also optionally includes an external "T" valve attachable to the exterior of the valve body of the present invention to provide convenient connections for a source of carbon dioxide to the laparoscope, surgical laser or both simultaneously.

Abstract: A mechanism, such as a motor driving a pump, creates a pulsating fluid flow. There is a control for varying the pulsation frequency independently of the fluid pressure or rate of flow. Another control varies the pressure or rate of fluid flow independently of the frequency of pulsation. Separate pulsatile lavage, irrigation, and aspiration functions are provided. In another aspect, the mechanism for producing the pulsating flow includes a fluid driving means, such as a reciprocating pump, and there is a means for varying the length of stroke of the driving means.

Abstract: An irrigation system for use in arthroscopic surgery including a variable RPM pump for introducing irrigation fluid from a fluid supply to a body irrigation site, a pressure control valve in the outflow from the irrigation site, a pressure sensor and associated controller for sensing pressure at the site and adjusting the pressure control valve for maintenance of the pressure within predetermined parameters, an override controller responsive to an inability to maintain pressure within the set parameters and responsive thereto to vary the flow rate of the pump, and associated display and signal components. The flow rate and pressure are individually and independently controllable.

Abstract: Apparatus is disclosed for the measurement and replacement of physiological fluids including a meter for measuring the amount of a physiological fluid flowing through the meter, a first conduit for continuously delivering the physiological fluid to the meter, a second conduit for replacing the measured amount of physiological fluid with a corresponding amount of a replacement fluid, and a pressure equalizer associated with the first conduit for equalizing the pressure in the physiological fluid flowing through the first conduit whereby the flow of the physiological fluid through the meter is substantially unaffected by pressure variations in the physiological fluid itself.

Abstract: In the surgical art of extracapsular cataract extraction, the lens capsule of the eye is irrigated and aspirated for cortex removal through use of a simple, inexpensive system of circulation of an irrigating solution, accompanied by automatic filtering of the aspirated material out of the solution such that the filtered liquid may be reintroduced. Means are included to produce unidirectional flow, and a manually operable bypass feature provides for safety and operator control of the entire procedure to assure accuracy, efficiency, exactitude and the best possible end results. The system is kept filled with the liquid solution in substantial absence of air therewithin.

Abstract: A pressure regulated system for an irrigation system including a reservoir of irrigation fluid, a pump, catheters for providing access to and egress from the irrigation site and a pressure regulation circuit, all connected in series with one another. The pressure regulation circuit includes a flow restriction branch having a normally-open valve and a variable orifice, diaphragm-operated, restrictor and a pressure accumulation branch, having a check valve, accumulator, and a normally-closed valve. A conduit running from the pressure accumulation branch to the diaphragm controls the pressure regulator. The operator may raise the pressure by closing the normally-open valve to direct pump flow to the pressure accumulation branch and thereby restrict the orifice of the pressure regulator until the desired pressure has been reached, and then releases the valve to maintain that pressure.