Abstract: There is disclosed herein a blood pressure alarm system for use in a dialysis machine whereby alarms may be activated, and a blood pump deactivated if the actual blood pressure increases above or decreases below predetermined levels. The levels are determined by setting a particular blood pressure point and setting the amount by which the pressure can vary above and below the set point. A memory is provided for storing the set point and preventing variation of the set point with time. The dialysis machine and alarm system can malfunction under certain conditions and protection circuitry operates the alarms if a malfunction occurs.

Abstract: A renal dialysis concentrate delivery system comprising at least two renal dialysis concentrate reservoirs, first supply valve means and supply conduit means. First supply conduit means connecting a first concentrate reservoir to the first supply valve means. Second supply conduit means connecting a second concentrate reservoir to the first supply valve means. Concentrate pump means operatively associated with the supply conduit means. Conduit means for transporting the concentrate toward a renal dialysis machine. Return conduit means for returning concentrate to the concentrate reservoirs. The first supply valve means may be a three-way valve.The return conduit means preferably includes a second three-way valve. Valve control means coordinate the positioning of the three-way valves so as to provide a first position wherein both valves are in communication with a first concentrate reservoir, and a second position wherein both valves are in communication with a second concentrate reservoir.

Abstract: An isolating and blood pressure transmitting apparatus for use in an extracorporeal blood treatment system or the like comprises a generally cylindrical, transparent plastic chamber with a housing having axially opposing inlet and outlet portions. The inlet portion is connected to a blood pumping and purifying portion of the system for receiving pressurized blood therefrom; the outlet portion is connected to a conventional pressure transducer which, in response to blood pressure transmitted thereto, controls blood pumping valving to maintain blood pressure in the system within predetermined limits. The chamber housing has a diameter and an axial length substantially greater than the diameter of the inlet and outlet portions, the chamber having an appreciable volume to absorb pressure surges. A thin flexible membrane, formed in a frustoconical shape is disposed across the housing to physically isolate the pressure transducer from the blood pumping and purifying portion of the system.

Abstract: This invention relates to the production of aqueous solutions of desired concentration for medical purposes which comprises passing water through a reverse osmosis column capable of retaining 100% of pyrogenic materials; and subsequently, in either order, passing the water through a sterilizer capable of eliminating 100% of bacterial material, and admixing, in suitable ratio, the water with a desired material or with a solution of such material of higher concentration than desired to produce said desired concentration solution.

Abstract: A dialysis apparatus, comprising an elongated flow passage with a water inlet and a brine outlet end, a pump at the outlet end for draining brine from the passage, a reservoir of brine concentrate in the passage, means for diluting the brine with water and adjusting salinity of the brine solution in the passage, a heater in the passage downstream of the reservoir for heating the brine solution after its salinity has been stabilized, a deaerator in the passage for breaking up the brine bubbles and removing air therefrom, a blood dialysis unit connected to the passage for purifying the blood of a patient whose bloodstream is connected to the unit, and pressure adjustment means connected to the passage for adjusting the pressure of brine passing to the unit.

Abstract: The peripheral surface of a coil of a filter web wound about a hollow shaft is covered by a liquid impervious flexible coating, and the outer periphery of a first end of the coil is secured to a supporting disc so that when liquid to be filtered is caused to pass through the coil in the axial direction thereof, the convolutions of the coil near a second end expand radially outwardly to trap contaminants in the spiral gap. Purified liquid collected at the first end of the coil is discharged through the hollow shaft. The filter unit is constructed such that a number of units can be readily connected in series.

Abstract: A fluid dual filter having a primary fine mesh filter element, a secondary coarser mesh element in parallel with the main or primary element and a plurality of bypass valves which are normally closed to block flow through the secondary filter element but which open at an elevated fluid pressure caused by blockage of the main filter element thereby allowing flow through the secondary filter element. The valves are located downstream of the secondary filter element in order to prevent their contamination by any foreign matter in the fluid to be passed through the filter.

Abstract: A gauge detecting the presence of a restriction placed upon an air stream passing through a filter in connection with an internal combustion engine, said gauge including a linear indicator to show the relative restriction present in the filter and including an indicator to show that the filter requires cleaning or replacement.

Abstract: A dual oil filter automatic switching system incorporating two oil filters and a switching oil valve and an oil pump, all connected together. The system also includes electric means incorporating a differential pressure switch and a latching relay, and an electric signal and an electrically-operative temperature switch are also disclosed. The oil valve is electrically responsive to the electric switching, and the valve directs the oil to either or both of the filters.

Abstract: Apparatus for indicating a clogged condition of a fluid filter or the like. The apparatus includes an electrical switch structure and a pressure-responsive element carried within the chamber to be responsive to the fluid pressure differential existing across the filter. The switch includes a threaded screw element adapted to adjustably engage the fluid pressure-responsive element in the chamber which may comprise a snap action element providing a positive instantaneous indication of the pressure across the filter reaching the preselected elevated value indicative of undesirable clogging of the filter.

Abstract: A hemispherical, transparent cover is provided in which a bellows having substantially the same hemispherical configuration is provided. A liquid having a different color than that of the bellows is filled between said transparent cover and the bellows whereby a difference in color may be perceptible from the outside of the transparent cover, depending on the pressure differential between the inlet side and outlet side of a strainer caused by clogging of its filter.

Abstract: A dialysis apparatus for machines such as artificial kidneys and heart-lung machines has a warning device activated to prevent air bubbles from entering the blood circulation system of the patient and controlled by the vertical position of a float in a float chamber where air is separated from the blood. The warning signal is triggered when the air/blood volume ratio in the chamber is increased so that the float sinks and closes off the outlet at the bottom portion of the chamber. Continued blood supply to the chamber compresses the air therein and the corresponding pressure increase is detected and used to generate a warning signal.

Abstract: A duplex filter system having two filterized fluid flow circuits for maintaining continuous fluid flow to an engine or similar liquid utilizing device during a filter change operation. A fluid control system is provided including liquid-obstructing air vent means for selectively venting air under pressure from an empty one of said two circuits while retaining fluid under pressure within the other said circuit during charging of said empty circuit, whereby fluid pressure within the system is regulated, and the fluid flow controlled. Detection means for detecting pressure within each of the two circuits.

Abstract: Waste water containing particulate matter is saturated with air or other gas by a dynamic mixer and ejected into a gravity filter system at a point above the filter media but below the water surface level. Upon entering the filter tank, the dissolved gas is released, forming small bubbles on filterable particles to float these particles to the surface for removal. The system further includes a back pressure valve at the sewage inlet port which, if obstructed, is automatically flushed. During the backwash cycle, the water level above the filter bed may be lowered to the level of a wash-through zone, and filtered water then pumped upward through the filter media, thereby carrying particles from the filter media out through the wash-through zone.

Abstract: A fuel filter bypass valve assembly includes a valve body having inlet and opposite sides. A movable member is peripherally sealed to the opposite side, and moves toward and away therefrom to define a variable volume chamber. Port means extends past the valve body for establishing communication between such chamber and the valve body inlet side. Yieldable biasing means is connected with the movable member for normally biasing same toward the valve body opposite side and biasing the entire assembly in a direction for positioning the inlet side against a valve seat. Cooperating stop means between the movable member and valve body limits movement of such movable member away from the valve body opposite side. The movable member and valve body are proportioned so that the pressure required to move the movable member away from the valve body against the force of the biasing means is substantially less than the pressure required to move the valve body away from the valve seat against the force of the biasing means.

Abstract: In accordance with the invention there is provided an extracorporeal blood circulation system including a drip chamber having a blood inlet in its top and a blood outlet in its bottom, such chamber during operation containing blood in its bottom portion and air in its top portion, an air passage communicating with the top of the chamber, an air pump communicating with the atmosphere and with the passage for pumping air through the passage from the chamber into the atmosphere and from the atmosphere into the chamber, and means for selectively actuating the pump to either pump air into or out of the chamber.

Abstract: A fluid filter has a fluid inlet, a fluid outlet, and a filter element in the fluid pathway, and is provided with a by-pass which includes a fluid pressure indicator. The by-pass comprises a cylinder attached to a cover and removable therewith. The cylinder has one aperture which provides fluid communication between the cylinder and the inlet and has another aperture which, when open, provides fluid communication between the cylinder and the outlet and hence provides a fluid pathway between the inlet and outlet which by-passes the filter element. A piston is movable within the cylinder responsively to fluid pressure from a first position where it closes the second aperture to a second position where the second aperture is open. The cylinder can be removed and mounted in a first position which provides both an indicating and a by-pass function or it can be rotated to a second position which provides only an indicating function.

Abstract: An apparatus for extracorporeal treatment of blood can carry through automatically such functions as dialysis and oxygenation compensating, in the process, for changes in the condition of the patient. A fail-safe monitor receives signals from a number of sensors all of which must provide signals within acceptable ranges in order for the apparatus to continue to function. Deviation of a signal outside the corresponding acceptable range for longer than a preset period causes the fail-safe monitor to stop the flow of blood taken from the subject and to activate an alarm. The apparatus may be so constructed that the ducting through which blood and other fluids flow can be caused to act as valves and pumps by suitably applied pressure. Also, such portions of the apparatus can be made in a form which is sufficiently economical so that they can be regarded as disposable. The apparatus may be designed so that it can be programmed for specific patients and for treatment of specific conditions.

Abstract: Apparatus for indicating when a swimming pool filter needs to be cleaned, which comprises a flexible diaphragm covering an opening in the conduit on the inlet side of a pool filter and a housing covering the diaphragm with a movable piston member inside the housing and engaging the surface of the diaphragm. Spring means urges the piston against the diaphragm to counteract pressure of water in the conduit against the diaphragm. A movable flag is operated by the piston means to indicate through a window in the housing when the piston has moved a predetermined distance.

Abstract: A method of ultrafiltration and an artificial kidney therefor, in which a membrane which is capable of simultaneous ultrafiltration and dialysis of blood is arranged to form a portion of the wall of a constant volume, closed loop vessel. A dialysis liquid is circulated in the vessel, while blood is passed on the opposite face of the membrane, and a fraction of the dialysis liquid is withdrawn from the vessel at a predetermined rate. The remainder of the dialysis liquid is kept at a constant temperature and is regenerated.

Abstract: An air filter restriction detection device communicating with the air stream passing from an air filter to the air intake of an internal combustion engine sensing a decrease in the supply of air being drawn through said air filter by said engine and the same being indicated by the linear movement of an indicating member in said device, said device indicating also when said air filter requires cleaning or replacement for lack of a sufficient supply of air being drawn therethrough.

Abstract: An apparatus for filtering fluids to remove solid discard particles therefrom, in which the apparatus includes a housing having a filter chamber, an inlet-side sealing chamber, and a discharge-side sealing chamber, a movable fluid inlet member which is movable into and out of the housing and which includes inlet-side and discharge-side bearing surfaces, and flexible sealing members which cooperate with the bearing surfaces in the sealing chambers to seal the filter chamber, a movable length of filter medium, and means for displacing the bearing surfaces and the movable length of filter medium, and which is operated by displacing the discharge-side movable bearing surface so that the movable length of filter medium may pass clear thereof, and displacing the movable length of filter medium clear of the discharge-side movable bearing surface to provide synchronized removal of the used length of filter medium from the filter chamber with discard particles associated therewith which are embedded therein and collec

Abstract: A combination visual and audible differential pressure warning signal device for fluid power, that is, hydraulic and pneumatic systems such, for example, as those employed in mobile equipment, industrial machinery, or the like. Thus, in a typical use of the invention, when the pressure in the hydraulic system, as in an oil filter, drops below a desired and predetermined normal, due to clogging of the filter, or for other reasons, the hydraulic pressure from the source, such as an oil pump, overcomes the combined pressure or force of the oil entering the signal device from the filter and the force of a resetting coil spring in the signal device, to actuate magnetic means which raises a normally concealed colored (red) visual warning signal into a position in which it may be seen through a window in the body of the signal device while, at the same time, closing an electrical circuit to an audio or audio-visual warning signal device.

Abstract: Method and apparatus for extracorporeally dialyzing the blood of a patient with only a single venipuncture including withdrawing blood from the patient through the venipuncture and forcing the blood along an arterial path to a dialyzer. Blood emerging from the dialyzer is then conducted along a venous path again to the venipuncture. The pressure is monitored in the extracorporeal system to trigger occluding devices which alternately open and close the arterial and venous paths so that undialyzed blood is taken from the patient and dialyzed blood is injected into the patient. The apparatus includes clamps actuated by a pressure monitor to alternately obstruct the arterial and venous paths. A blood pump may be controlled to operate as one of the clamps. In an alternative embodiment, blood is circulated at a comparatively high flow rate throughout the system. A clamp is provided in one of the arterial or venous lines, said clamp being controlled by a pressure monitor.