Abstract: A wear-preventive air-charger piston structure is provided. The piston rod has a top forming a piston top seat on which a piston ring is disposed. The piston ring is covered with a top cover that is combined with the piston top seat. The top cover is provided with an airtight plate mounted thereto to form a complete piston structure. A buffering element is arranged between the piston top seat and the piston ring. The buffering element has an outside diameter smaller than the piston ring, so that when the piston ring, which is driven by a crankshaft to do an up-and-down movement, is put in an inclined oscillating condition and at a high position of an oscillation side, the buffering element functions to absorb the stress acting on the piston ring at the high position of the oscillation side to effectively prevent detachment and breaking of the piston ring.

Abstract: A metering mechanism includes a body mounted in a sleeve covering the top and an adjustment nut covering the bottom, the adjustment nut threaded to the sleeve, the screw connection then causing rotation of the adjustment nut with respect to the body of the metering mechanism, the body being extended by a valve seat that can be closed by a valve, able to receive a plunger of which the reciprocating motion permits intake at the valve, the travel of the plunger depending on the screw position between the adjustment nut and the sleeve. The metering mechanism further includes a rotation lock between the adjustment nut and the body of the metering mechanism to prevent the adjustment nut being screwed or unscrewed on the sleeve. Also disclosed is a method for locking and unlocking such a mechanism, and to a proportional metering pump incorporating such a mechanism.

Abstract: A fluid handling device includes a receiving container with a piston arranged therein in a displaceable manner, such that the volume of a fluid receiving reservoir may be changed by a displacement of the piston. In addition, the fluid handling device includes an actuation mechanism configured to displace a carrier bearing upon actuation of the former. Finally, the fluid handling device includes a spring mechanism configured to transfer a force from the carrier bearing to the piston so as to effect, in response to displacement of the carrier bearing in a first direction, a displacement of the piston within the receiving container such that a volume of the fluid reservoir is increased.

Abstract: Dispenser (1) for the dosed dispensing of liquid media, with a container (3) for holding a liquid medium (4), a manually actuated pump (5), which is arranged on the container (3) and comprises a flood chamber (6) into which liquid medium (4) flows when the container (3) is turned over, for which purpose the flood chamber (6) is fluidically connected at the inlet end to an outlet opening (7) of the container (3), and a dosing piston (8), which is displaceable by an actuating stroke, is arranged in the flood chamber (6) and expels dosed medium (4), and a media channel (9) extending through the dosing piston (8) is widened at the inlet end as a volumetrically defined cylinder portion (10) into which a plunger piston (11) protruding into the flood chamber (6) engages as a pressure piston in order to expel medium (4) introduced by gravity into the cylinder portion (10) of the dosing piston (8).

Abstract: Described herein is a material moving apparatus that includes a chamber into which a compressible material is introduced. The chamber includes an input opening for receiving the material, a discharge opening and a sealing mechanism to prevent flow of air or other gasses between the input opening and the discharge opening. In one embodiment, the material moving apparatus can be used to introduce compressible biomass into a gasification reactor.

Abstract: A pump priming apparatus including a housing through which fluid object material may be urged to flow, the housing including an intake portion and a pumping portion downstream from the intake portion. The apparatus further includes a piston assembly carried for reciprocation in the housing, the piston assembly and the housing being configured such that a partial vacuum is developed in the pumping portion of the housing as the piston assembly moves through the pumping portion of the housing toward the intake portion of the housing and such that the partial vacuum is substantially released upon the movement of the piston assembly into the intake portion of the housing, thereby causing the fluid object material in the intake portion of the housing to flow into the pumping portion of the housing.

Abstract: For the purpose of providing a thin pump designed to decrease the number of parts, the pump is provided with a rectangular parallelepiped cylinder (3) and a piston located inside of the cylinder, wherein the piston (4) reciprocates and oscillates in the cylinder (3) to vary capacity of the pump chamber (12) and to make the intake port (5) and the outlet port (6) open alternately, so that fluid is sucked from the intake port (5) into the pump chamber (12), compressed and discharged from the outlet port (6).

Abstract: This invention provides a sealing mechanism for sealing the piston-cylinder unit of a reciprocating diaphragm pump to ensure that the piston-cylinder unit is permanently and reliably sealed while being simple to assemble. The invention further provides a piston-cylinder unit which has almost no play in the micrometer (&mgr;m) range, and which is sealed by hydrodynamically sealing a slot thereof.

Abstract: A lubricator for delivering grease lubricant to lubricating locations of a machine is coupled to a grease container and has a work chamber in which a delivery piston reciprocates. To ensure that a compressible medium, such as air which has been drawn into the work chamber is rapidly expelled therefrom, the work chamber is divided by a grease return device into a compressing portion and a delivery portion. Triggered by a sufficiently high pressure level which prevails in the compressing portion and which is present only during grease delivery, an otherwise blocked return connection is established between the compressing portion and a supply port which couples the grease container to the work chamber, as long as the head of the delivery piston, in the course of its grease delivery stroke (forward stroke) is situated in the compressing portion.

Abstract: The present pump design with the elimination of a separate hydraulic fluid path from the cylinder dramatically improves the efficiency and pressure achieved by the pump by 15% as a result of reducing the number of chambers provided in the pump interior. It is, however, imperative for reasons not completely understood that in order for these efficiencies to be obtained that a reservoir of oil be located adjacent the main oil intake volume to ensure quick filling of the main oil intake volume as the piston cycles to its pressure stroke. This prevents cavitation of the pump.

Abstract: An improved reciprocating plunger pump boasting a self-aligning plunger assembly, a selectively removable plunger guide cartridge, and an improved seal cartridge assembly.

Abstract: A pump 1 comprises a chamber 2 having a inlet opening 22 and an outlet opening 21. The chamber 2 extends between a first main wall 30 and a second main wall 40. The first main wall 30 is a triangular bottom wall of a body 3. The second main wall 40 is a part of a triangular bottom wall of a tub 4. The body 3 is tiltable relative to the tub 4 so that the volume of the chamber 2 is variable. The pump 1 comprises an outlet valve for blocking the outlet opening 21 when the volume of the chamber 2 is increased and an inlet valve for blocking the inlet opening when the volume of the chamber 2 is reduced. The outlet valve is formed by a first portion 31 of the body 3. This first portion 31 of the body blocks the outlet opening when the body is urged against the outlet opening 21. The inlet valve is formed by a second portion 32 of the body 3. This second portion 32 of the body blocks the inlet opening when the body is urged against the outlet opening 21.

Abstract: A metering device for the precision feeding of a liquid, such as, for example, an oil lubricant. The device has a fluid supply chamber with a working medium such as oil and which in turn is in open communication with a metering chamber also containing the medium fluid. A fluid pumping piston passes through the supply chamber and then into the metering chamber. Upon entering the metering chamber, the pumping piston passes through an annular flexible seal of generally U-shaped cross section that has a pair of axially extending lips which act, respectively, along the piston and the metering chamber to thereby form a one-way valve therebetween. The piston forces the fluid out of the metering chamber and the volume displaced by the piston can be adjusted by adjusting the axial position of the metering chamber and thereby vary the extent to which the pumping piston enters the metering chamber.

Abstract: A reciprocable liquid pump having a priming cylinder affixed beneath the lower valve housing, and a priming piston rod affixed to the lower end of the pump piston valve assembly. A priming piston and priming valve are affixed to the lower end of the priming piston rod, the priming piston being slidable over a limited range of movement along the priming piston rod and having a central opening with a beveled valve seat. The priming valve forms a conical valve surface which is engageable against the priming piston valve seat to provide a controllable flow path through the center opening of the priming piston.

Abstract: In a priming piston loading double acting pump for high viscosity materials, the shovel plate assembly is formed of a flexible, abrasion resistant disk or cup. The disk may be made from silicon rubber and the cup may be made from a glass filled Teflon polytetrafluoroethylene material. The clearance between the plate assembly and the intake cylinder is essentially zero to allow for a build-up of a vacuum as the plate assembly moves downwardly and out of the intake cylinder to greatly enhance the loading ability of the pump.

Abstract: A device for dispensing of small volume comprises a pump associated with a container of the substance to be dispensed, the pump comprising: a hollow pump body; and a piston sliding inside said pump body in sealing contact with the pump body around a circular periphery of diameter D2; wherein the pump further includes: a push rod including a central channel in which a valve seat is formed, the push rod sliding in contact with the pump body around a circular periphery of diameter D1 less than D2; a punch secured to the piston and capable of bearing in sealed manner against the valve seat; and resilient means urging the piston against the valve seat.

Abstract: A piston pump shaft sealing system is provided which prevents particles released from the shaft seal, as a result of wear from entering and contaminating the fluid being pumped. The system features a permeable, deformable disc disposed between the seal and the displacement chamber of the pump. The piston shaft extends through a centrally exposed hole in the disc. In its undeformed state, the hole in the disc is smaller than the diameter of the piston shaft so that when the shaft is forced through the hole, the edges of the hole are pressed against the surface of the shaft, thereby scraping off seal particles deposited on the shaft. Forcing the shaft through the hole also deforms the disk into a conical shape, thereby forming an annular cavity between the disc and the seal which surrounds the piston shaft. The cavity serves to capture and retain the sealed particles, thereby preventing them from entering the fluid.

Abstract: A dual piston alternately reciprocating pumping apparatus utilizing, in part, a pressure based precompression stroke to provide product at a substantially uniform discharge pressure. In operation, a first feed piston is advanced through a first feed cylinder to discharge product therefrom, during which time a second feed piston is retracting within a second feed cylinder to obtain a product charge therein. The second feed piston reaches bottom dead center and thereafter advances through the second feed cylinder on a precompression stroke, during which no product is discharged from the second feed cylinder. After a predetermined pressure related to that within the second feed cylinder is detected, further advancement of the second feed piston is terminated and is not reactivated until the first feed piston nears top dead center. Therefore, a product having a substantially uniform discharge pressure is provided.

Abstract: An improved pumping device for delicate or easily damaged products is provided with a hopper, or other system for holding the products, and at least one, and preferably two, synchronized piston pumps positioned proximate to the bottom of the hopper. The piston pumps displace the product from the interior of the hopper into a consolidating feed manifold where the product is then dispensed through a discharge conduit into suitable receptacles. Each of the piston pumps preferably includes a pump cylinder with a fixed, elongated, cylindrical sleeve housing and an elongated rotatable cylindrical sleeve positioned within the sleeve housing, both enclosing a piston chamber. A first longitudinal opening or access port is formed in the fixed sleeve housing and a corresponding second longitudinal opening or access portion is formed in the rotatable sleeve.

Abstract: An apparatus includes a tilt piston having a piston head. The piston head is reciprocally disposed within a cylindrical bore formed in a housing, the bore being oriented along an axis. A seal is mounted circumferentially about the piston head. The seal has an outer diameter that exceeds an inner diameter of the cylindrical bore. The seal extends radially in a first direction having an axial component. A support is mounted circumferentially of the piston head adjacent the seal. The support has an outer diameter less than the outer diameter of the seal. The seal is a continuous annular ring which may be of a circular or rectangular cross section. The seal and the support may be formed as a unitary member or may be two distinct elements. The support contacts the bore during a portion of travel of the piston within the bore.

Abstract: A sanitary material moving pump having a ram mounted for rreciprocal movement in a pumping chamber. An elongte tubular housing is connected at one end to the ram for purposes of reciprocal movement of the ram to move material through the pumping chamber. A piston shaft is mounted in stationary relationship relative to the pumping chamber in alignment with the design pumping axis of the pumping chamber. The end of the housing opposite the ram extends outward of the pumping chamber and is installed on the working end of the piston shaft. A piston is mounted on the inside end of the piston shaft. Hydraulic fluid lines communicate with opposite sides of the piston to reciprocate the housing on the piston shaft and the ram in the pumping chamber. Apparatus is provided for correctly adjusting the alignment of the hydraulic power unit to be as coincident as possible with the design pumping axis of the machine.

Abstract: An asymmetrical or relieved piston is provided in a fluid motor or a pump. The piston is rigidly connected to one end of the connecting rod, the opposite end of which is pivotally connected to a rotating crankshaft. The piston has a relieved upper and lower section each of which has a partial spherical surface. When the piston is tilted in one direction through half of a rotation of the crankshaft, a seal is formed between the partial spherical surface and the wall of a cylinder. During the other half of the rotation, the relieved piston is tilted in the opposite direction, the seal is broken, and fluid bypasses the piston from the upper half of the cylinder volume to the lower half or vice versa. A floating poppet valve is utilized in the engine, and a floating check valve is utilized in the pump of the described single piston embodiments.

Abstract: Modular positive displacement apparatus for dispensing precise quantities of a fluid product including a dispensing unit and an actuator unit. A housing of the dispensing unit defines a reservoir, a chamber and closure valve. The reservoir is divided into a plurality of sub-reservoirs, which contains the product. The walls dividing the reservoir into a plurality of sub-reservoirs provide guide surfaces for self-alignment of a product piston in the reservoir. A deformable diaphragm isolates the reservoir from the mechanism which actuates the valve to prevent undesirable entry of the product. The dispensing unit is readily removable from the actuator unit and can be readily replaced with another dispensing unit. Different nozzle sizes can also be accommodated. The extent of the closure opening is adjustable in discrete increments.

Abstract: A vane pump in which the ports for passage of highly viscous material pumped are widely dimensioned and the clearances, in particular around the rod which carries the vane, are great. The invention applies to the pumping of materials of the type having a base of butyl rubber and/or polyisobutylene, and in general of materials exhibiting a viscosity greater than 35,000 poises.

Abstract: A reciprocating piston compressor of the type having the piston fixed to the connecting rod. The centerline of the cylinder is offset from the centerline of the crankshaft in a direction which reduces the maximum angle between the piston and the cylinder axis during the compression stroke. The offset reduces the maximum side loading on the piston to in turn reduce piston seal wear.

Abstract: A pump assembly (1) for an atomizing piston pump comprising a piston (16) slidably located in a cylinder (4), a variable volume fluid storage chamber (5) in communication with the cylinder on one side of the piston, means (18) for varying the volume of the chamber, resilient means (17) urging the varying means into a position corresponding to the minimum volume of the chamber, a fluid flow passageway (30, 31) through the piston, a resilient valve member (25) normally closing the passageway and deforming means (23) for deforming the valve member so as to open the passageway only after the piston has moved relative to the cylinder by a predetermined amount greater than zero. The pump assembly has application to dispensing metered doses of medicinal products and ensures that the dispensed dose is independent of finger pressure applied to the actuator.

Abstract: A liquid additive injection pump has a hydraulic motor comprising a differential piston assembly reciprocable in a housing under the urging of a primary liquid into which an additive is to be injected. The piston assembly includes valves to effect the transfer of a primary fluid charge from the pump motor to a discharge passage and to effect reciprocation of the piston assembly. The motor piston is connected to a central axially disposed piston rod which extends into an additive injection pump cylinder. In one embodiment a floating additive injection pump piston has a stack of displacement control washers engaged therewith and disposed on the piston rod. In another embodiment the pump piston passes through a seal member between a pump chamber and a bypass chamber and an elongated spiral groove formed on the periphery of the pump piston determines the effective displacement of the pump.

Abstract: A thrust piston pump for an active substance dispenser has two equiaxial, position-rigid, interconnected pistons running in the same direction, namely a pump piston passing in and out of an otherwise closed pump chamber and a larger presuction pistion located downstream thereof, in whose associated pressure chamber is located the pump chamber end opened by the passing out of the pump piston. This leads to a very accurate dosing of the discharged active substance quantity, accompanied by a simple construction and high operational reliability.

Abstract: A discharge pump for expelling fluid from a container comprising a pump chamber, aligned plungers disposed in said pump chamber movable in reciprocation therein and in unison and relative to each other to alternately trap a charge of fluid therebetween, isolate the trapped charge from the container and discharge the trapped charge from the container.

Abstract: An air-operated reciprocating pump is designed for use with a wide variety of materials having widely varying viscosities. The pump has a stroke which is adjustable so that the piston can operate either entirely within the cylinder or can extend out the bottom end of the cylinder at the end of the stroke for materials having an extremely high viscosity. The stroke adjustment is easily accessible in the area between the pump and the air motor.

Abstract: A pump seal is provided for use in a pump suited to move high viscosity and abrasive materials. A piston in the pump has a substantial amount of clearance relative to the cylinders in which it operates with the seal providing substantially the only contact in sealing between the piston and the cylinders. The seal is formed of a relatively soft, elastomeric material which is normally of a plainer, annular shape. Along with a rigid annular ring plate, the elastic ring is sandwiched between the closure member and housing member. The ring plate has a curved surface facing the closure member which serves to backup and support the relatively soft elastic ring under pressure.

Abstract: A pump for forwarding liquids is described which has at least one pump chamber with inlet and outlet valves and also a plunger which periodically varies the volume of the pump chamber. To avoid the problems of dry running with very rapidly running pumps, and in order to overcome the resulting danger of destruction, the pump is arranged so that the closing force of at least one inlet valve of each pump chamber is controlled in dependence on the movement of the displacement member.

Abstract: A dosing pump (1) is created allowing to accurately dose a medium to be dosed as a function of time or of a flow rate. The dosing pump (1) utilizes a predelivery obtained by a diaphragm (11) as well as a piston-cylinder-pump for dosing. The pump cylinder is connected with the suction conduit so as to prevent any pressure drop when the piston emerges from the cylinder. A crystallization or polymerization of the dosing agent in the piston-cylinder-means is thereby prevented.

Abstract: A dosing pump (1) is produced, with which a precise dosing is possible as a function of the time or of a flow rate. The dosing pump (1) operates with a preliminary transport obtained by means of a diaphragm (11). The stroke volume of the diaphragm (11) is greater than the volume of the pipe element present between a preliminary transport chamber (9) and a dosed medium tank (16). It is thereby made possible to omit a return pipe and a suction valve and a pressure valve.

Abstract: A hand carried, motor driven pump which will pump at high or low pressure, depending upon the size of the plunger used. The pump is used for high pressure lubricant, up to 9,000 lbs., to a high volume of fluid, such as Diesel oil, water and the like at low pressure. The pump is used in practically all industries in which machinery is to be lubricated by grease under high pressure and where liquids need to be transferred or pumped from one container to another. The present pump is particularly adaptable for use on heavy agricultural machinery, where portability is essential.

Abstract: A ram type pump is disclosed for pumping manure from a collection area to a storage area. The pump has a hollow cylindrical housing having a transfer portion and an actuator portion. Manure is pushed through the transfer portion by a reciprocating cylindrical ram slidably located in the housing. The ram is operated by a hydraulic actuator located in the housing actuator portion. The housing actuator portion is releasably coupled to the transfer portion. This releasable coupling retains a removable bearing and seal assembly concentrically located for sliding, sealing engagement of the ram. The housing transfer portion includes a guide bearing assembly for concentric sliding engagement of the ram during reciprocating movement of the ram. Also, the housing actuator portion includes radially disposed guide means for quick axial alignment of the ram in the housing.

Abstract: A dispensing pump having no check valves includes upper and lower mechanically-joined pistons which are moveable together through respective upper and lower cylinders. As the pistons are moved in one direction toward a rest position the cylinders are initially pressure-isolated and the upper piston aspirates spray liquid into the upper cylinder while the lower piston aspirates air into the lower cylinder. Before reaching the rest position the pistons unblock flow communication between the cylinders to permit liquid from the upper cylinder to fall into the lower cylinder. During movement of the pistons in the opposite direction the cylinders are again pressure-isolated and the lower piston forces liquid from the lower cylinder through a spray outlet under high pressure.

Abstract: A barrel filler is provided for facilitating, filling and compacting of comestibles, such as cookie dough or the like in a dispensing mechanism for extruding the comestibles. The barrel filler is designed for placing comestibles in a dispensing mechanism having a centrally located shaft with a piston thereon. The barrel filler is designed to permit sanitary cleaning thereof.

Abstract: A pump mechanism for delivering ink or the like writing fluid from a reservoir to a point of utilization such as a writing device. The mechanism includes a piston slidable in a cylinder for drawing ink into the cylinder during a suction stroke and discharging the ink during a pumping stroke. The cylinder is formed by a cylinder wall which includes a frusto-conical portion tapered inwardly in a direction away from the piston. The piston comprises a single plastic member having a forward end portion which faces and cooperates with the tapered portion of the cylinder wall and which has an outside diameter which is greater than the smallest diameter of the tapered cylinder wall portion, whereby the forward end portion of the piston engages the tapered cylinder wall portion as the piston moves forward during a pumping stroke.

Abstract: A material dispensing and metering piston pump comprising, in combination, a piston cylinder, an inlet defined in said cylinder for material to be dispensed, and an outlet defined in said cylinder for the said material, the inlet and the outlet being axially spaced from one another, and a piston comprising a piston rod and a piston head, the piston head comprising a member having a peripheral skirt outwardly and forwardly projecting therefrom, said member having one or more apertures extending there-through, there being a sealing member mounted on said piston rod, said member and said sealing member being movable relative to one another, said sealing member acting to seal said apertures when said member with said peripheral skirt and said sealing member are in one relative terminal position, the arrangement being such that the member and sealing member co-operate to seal said apertures when the piston head assembly moves material towards said outlet and to open said apertures when the piston head is withdrawn

Abstract: A pump for fluent materials, and especially suitable for heavy and abrasive materials, has a piston in substantial clearance relation within a cylinder and operable in a pumping stroke to drive into a combination valving, wiping and sealing elastomeric ring about the discharge portion from the cylinder, so that the pumped material has minimal drag and wearing contact with relatively moving parts in the pump. The pump is adaptable for double action and proportional pumping.A self-reversing piston-driving fluid actuated motor is provided.

Abstract: A high pressure piston pump especially suitable for moving heavy high viscosity and abrasive materials, which has its piston in substantial clearance relation in a cylinder, is operable in a pumping stroke to drive into a flexibly deflectable, elastic combination valving, wiping and sealing elastomeric ring which not only maintains tensioned sealing engagement with the piston but also reacts to pump pressure to improve the sealing engagement during pumping stroke of the piston, and permits relaxation of grip on the piston and leakage forwardly along the piston during return stroke suction in front of the piston.

Abstract: A hopper having a bottom opening into an open topped chamber portion of a housing which defines a discharge passageway leading from the chamber to a discharge end portion. A piston is mounted for reciprocatory movements in the chamber portion and passageway. The piston having a pumping surface normal to the direction of its movement and facing the discharge end portion of the passageway. The piston has an opposite surface which slopes angularly upwardly toward the pumping surface. A check valve is disposed in the passageway at the discharge end portion of the passageway.

Abstract: This invention relates to liquid metering pumps and according to the invention such a pump comprises a cylinder permanently connected to an inlet passage for the liquid and in which said cylinder a plunger piston is arranged to slide said piston co-operating with a sealing gland on the inlet side. The piston is urged by an elastic member into contact with a reciprocable actuating rod which co-operates with a sealing gland on the outlet side. The two sealing glands are separated by a spacer to form an annular chamber around the plunger piston and the actuating rod.

Abstract: A metering pump including a pump body having a bore for receiving a flowable composition to be dispensed, feed inlet means communicating with the bore, and spaced outlet means including a check valve, for discharging the composition. A pressure chamber is defined intermediate the pump inlet and outlet. The chamber has an inlet, and an outlet communicating with the pump outlet through the check valve. A piston is mounted for axial reciprocation in the bore between a first position at which the piston is withdrawn from the pressure chamber inlet, and a second position at which the piston passes at least partially into such inlet. The pressure chamber inlet is bounded by sealing means including an annular sealing surface which converges in the direction of the pressure chamber, to a diameter less than that of the piston, whereby the surface may slideingly engage and seal with the piston upon the latter entering the pressure chamber.

Abstract: The invention is concerned with an improvement in a manually activated fuel priming pump for an internal combustion engine comprising a housing having a barrel communicating at its lower end with a flange disposed transversely to the barrel. A plunger communicates at its upper end with a handle, the plunger being reciprocally mounted in a chamber of the barrel to selectively pump fuel from a first to a second valve located in the flange of the housing. The plunger has around the periphery thereof means slidingly sealing it with low friction against a bore defining the chamber. The improvement of the invention comprises a member co-axial with the plunger and extending therefrom towards the flange and member-bore seal means slidably sealing said member to said bore and disposed to allow flow of said fuel from a space within said chamber between said plunger and said flange to said second valve and to retard flow of said fuel in a reverse direction.

Abstract: Double action piston pumps incorporate a check valve mechanism to control material flow between the pumping chambers and the pump outlet. The present disclosure includes an improved check valve mechanism which is mounted in the pump in free floating relation with the pump piston to permit more efficient closing of the check valve and therefore provide more efficient and consistent output flows. This check valve has an inner annular surface surrounding the pump piston and is separated therefrom by a clearance of between .035 and .085 inches. When the check valve is closed, during part of the pumping cycle, it seats on an improved valve plate thereby preventing a reversal of flow. The valve plate on which the check is seated is in a close dimensional tolerance with the piston rod to effectively scrape the piston rod clean thereby preventing the adhesion of the material being pumped to the piston rod.

Abstract: The invention relates to a cylinder and plunger pump for transferring very small quantities of dosed liquids.The purpose of the invention consists in the realization of relatively small pumps of which the piston need only perform a very small reciprocating movement in order to pump up the liquid, whereby no disturbances may occur.