LIQUID DISPENSING PUMP

Abstract: A liquid dispensing pump in the form of a manually operated trigger sprayer includes a thimble-­ shaped valving element (26) providing inlet and outlet valves (31, 34), and located within a cylindrical portion of the pump body. In one embodiment, a pressure accumu­ lation chamber (35) is defined between the pump body and the valving element (26), and a pump piston (37) operates within the valving element and defines therewith a pump chamber in open communication with the accumulation chamber via spaced, flexible and extendable straps which interconnect the inlet and outlet valves for permitting a portion of the valving element to move axially into a discharge valve opening position. Vent valving is effected by either the pump piston or the valving element during inward reciprocation movement of the piston. In another embodiment, the sprayer is converted into the throttle pump by the provision of a pump piston which operates within the cylindrical portion of the pump body.

Description: This invention relates generally to liquid dispensing pumps of the form disclosed in U.S. patent 4,046,292, which includes: a pump body defining a pressure accumulation chamber having an axially directed inlet port for communication with a source of flowable product to be dispensed, and an outlet port at the periphery of the said chamber; a unitary element includ­ ing an inlet check valve controlling the said inlet port and further including an outlet valve disposed for axial movement in said chamber from a closed position which it blocks communication between said ports to an open posi­ tion in which it establishes communication between said ports; a pump cylinder defining a pump chamber coaxial with the said pressure accumulation chamber and in open communication therewith; a pump piston reciprocable in said cylinder independently of the movement of the said outlet valve; resilient means normally urging the said outlet valve toward its closed position; and means for manually reciprocating said piston. The present invention aims at the provision of a modified form unitary element which is of simple con­ struction, being simple to manufacture and to assemble with the pump and which renders the pump easy to operate whilst effecting a dripless discharge. The invention is mainly characterized in that the said unitary element comprises a thimble-shaped element having at its inner end a transverse end wall including a central portion constituting the said inlet valve, the said wall being formed with a plurality of elongate openings establishing the open communication between the said chambers, and defining therebetween flexible straps which facilitate relative axial shifting of the said inlet and outlet valves during a pumping operation. Some pumps in accordance with the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a vertical sectional view of a dis­ pensing pump according to one embodiment of the invention; Figures 1A and 1B are sectional views similar to Figure 1 showing details of quick opening and slow open­ ing discharge valves, respectively; Figure 2 is a perspective view of the thimble-­ shaped member according to Figure 1; Figures 3, 4 and 5 are sectional views, similar to Figure 1, of other embodiments according to the inven­ tion, with portions only of the pump being shown; and Figure 6 is a vertical sectional view of yet another dispensing pump according to the invention. Turning now to the drawings wherein like reference characters refer to like and corresponding parts through­ out the several views, a liquid dispensing pump in the form of a trigger operated sprayer is, according to one embodi­ ment of the invention, generally designated 10 in Figure 1 and includes a pump body 11 defining an inlet passage 12 and an outlet passage 13. A conventional dip tube 14 is received within the inlet passage and extends into a con­ tainer (not shown) of product to be dispensed in a manner well known in the art. A container cap 15, having internal threads or other container securement means, engages an annular lip 16 of a circular section of the pump body for mounting the sprayer on to the neck of the container, and if desired a seal ring 17 may be disposed between the lower end of the pump body and the upper end of the container neck. The pump body further includes a pump cylinder 18 having a conical end wall 19 containing an inlet port 21 in which the inlet passage terminates. The cylinder axis lies between and extends at an angle to inlet and outlet passages 12 and 13. The outlet passage 13 extends from an outlet port 22, located in the wall of cylinder 18, through a nozzle plug 20 fitted within the pump body, and terminates in a discharge orifice located in a nozzle cap 23 in engagement with the plug. Also, the pump body is provided with an integral shroud 24, which may other­ wise be made separately and assembled in place and having a contoured wall 25 shaped to fit against the hand when the trigger sprayer is grasped by the operator. A unitary, thimble-shaped, valving element 26, shown in more detail in Figure 2, is disposed within cylinder 18 and has at one end thereof a conical transverse end wall 27 substantially corresponding in shape to end wall 19. Wall 27 includes a plurality of flexible and extendably-shaped straps 28 which extend from adjacent the apex of the conical end wall to the base and are defined by openings 29 which may be of maze-like configuration. Thus, the tip of wall 27 is capable of axially shifting relative to the remainder of element 26, and vice versa. Instead of openings 29 of the configuration shown, S-­ shaped, or the like, openings may be provided to facilitate such relative axial shifting movements, without departing from the invention. The central portion of wall 27 constitutes an inlet check valve 31 for controlling inlet port 21, and straps 28 are neutral from a pressure standpoint. A pressure accumulation chamber 32, shown in detail in Figure 1A, is defined between the inner end of element 26 and the confronting surfaces of the pump body. Thus, the inlet port is essentially axially directed at one axial end of the chamber 32 and the outlet port opens radially from such chamber at its periphery. A ring 33 extends from wall 19 toward element 26, and an annular flange 34 on element 26 adjacent wall 27 constitutes a discharge or outlet valve which seats against ring 33 in a discharge closing position, the flange defining an annular groove 35 with the body of element 26 so as to effectively form an extension of accumulation chamber 32. An annular flexible lip seal 36 on element 26 is located adjacent the free end thereof, although may lie further inwardly toward flange 34 if desired, for slideably engaging the inner surface of cylinder 18 in a fluid tight manner. A pump piston 37 in the form of a thimble or cup-shaped element extends into valving element 26 and has a flexible, circular skirt 38 adapted for sliding along the inner surface of the valving element in fluid tight engagement therewith. The piston thus defines a variable volume pump chamber 39 with element 26 and is in open communication with accumulation chamber 32 via openings 29. Moreover, an annular, flexible skirt or lip seal 41 on piston 37 surrounds the open end thereof and is slideable along the inner surface of cylinder 18 in a fluid tight manner to define an annular chamber therewith, as shown. Thus, cylinder 18 and element 26 define cylinder means having a bore engaged by lip seal 41 of the piston and a counterbore engaged by skirt 38 thereof. A return spring 42 encircles piston element 37 and extends between flange 41 and the outer rim of element 26 for normally urging the outlet valve toward its closing position. Co-operating snap beads on seal 41 and the inner surface of cylinder 18 may be provided for retaining the piston within the pump body. Sprayer 10 further includes a trigger actuator in the form of a lever 43 having a trunnion 44 to facilitate mounting the lever for pivotal movement about the axis thereof on the pump body. For manual recipro­ cation of the piston, the lever has a pair of spaced actuator flanges 45 (only one being shown in Figure 1) spaced apart at outer ends 46 thereof a sufficient dis­ tance for bearing against outer circular rim 47 of the piston. Alternatively, a rod-like member may extend between the trigger actuator and the end wall of the piston, the rod-like member being integral with either the piston or the trigger member, or may be separate from both. A container vent port 48 is located in the lower region of the wall of cylinder 18, outwardly of the chamber 39 and at least one axially disposed rib 49 is provided in the upper region of the inner surface of cylinder 18 for flexing seal 41 radially inwardly when in contact therewith during inward movement of the piston, so as to define a passage from atmosphere through the open end of the cylinder 18, past the seal 41 and through vent port 48 to the inside of the container so that dispensed product is replaced with air during the dispensing opera­ tion. As shown, vent port 48 is inwardly spaced from seal 41 in both non-pumping and pumping positions of the piston. Also, the vent port 48 inherently functions as a sump drain port which establishes communication with the aforementioned annular chamber and the interior of the container. Thus, with this arrangement, any leakage of product from pump chamber 39 around piston skirt 38 is purged from the annular chamber into the container through port 48, any leakage of product from the con­ tainer through port 48 and outwardly of cylinder 18 is prevented, and any abrasion of piston skirt 38 or lip seal 41, during pumping or during assembly of the piston 37, are all avoided. In operation, after the pump chamber is primed with product to be dispensed, the piston is inwardly reciprocated upon manual actuation of the trigger lever against the force of spring 42 and the enclosed fluid to thereby increase the pressure within the pump chamber, which pressure maintains inlet check valve 31 closed during the compressing stroke. As the compression force increases, there will manifestly be a progressively increasing fluid pressure within accumulation chamber 32 until such pressure creates a force on the outer end surfaces of valving member 26 which extend from the pump chamber diameter outwardly to flange 34 sufficient to overcome the opposing force of the spring. This will result in movement of flange 34 in an axial direction away from ring 33 to thereby open the discharge passage whereby the contents of chamber 39 will be discharged under pressure through discharge passage 13. Such dis­ charge will continue as long as the pressure within the pump chamber is sufficient to overcome the force of the return spring. However, when the pressure within the accumulation chamber is reduced, either by reduced actu­ ating force on the piston or through approach of the piston to the end of its pressure stroke, so as to pro­ duce insufficient force to overcome the return spring, the spring will act to return the outlet valve immediately to its closed position, thereby affording an abrupt, sharp cutoff of the discharge to minimize dripping of product from the discharge nozzle. Since the outlet valve (or flange) 34 makes tangential contact (Figure 1A) with ring 33, and the outer surface of the discharge valve is radially inwardly spaced from the wall of cylinder 18, a quick acting discharge is effected as soon as this tangential contact is broken. On the other hand, a modification is shown in Figure 1B wherein a flange (or outlet valve) 34 a is out of contact with ring 33 in the discharge closing position and is instead in fluid tight engagement with the wall of cylinder 18 for covering the outlet as shown. Thus, the free end of the flange 34 a slides along the wall of cylinder 18 at a larger diameter than flange 33 until the outlet port 22 is uncovered during the opening movement, so as to effect a slow opening discharge. The aforedescribed quick opening and slow opening discharging is likewise included in the dispensing pump disclosed in U.S. patent No. 4,402,432. On the succeeding outward stroke of the piston under actuation of the return spring, after the closing of the discharge as aforedescribed, the outlet valve will remain seated to prevent back flow of liquid through the outlet into the accumulation chamber, while the resulting reduced pressure within chambers 32 and 39 will open inlet valve 31 against the resilience of straps 28, there­ by enabling a charge of flowable produce from the con­ tainer to be drawn upwardly through the dip tube and the inlet port into the intercommunicating accumulation pump chambers. Outlet valve 34 will remain closed throughout the entire outward stroke of the piston and, at or near the end of such stroke, the inlet valve will be reseated over the inlet port, under the elastic memory action of straps 28 tending to retain the conicity of wall 27, in preparation for the next ensuing compression stroke of the piston. Reciprocation of the pump piston continues for as long as is necessary to dispense the desired amount of product from the container to which the sprayer is applied, following which the outlet valve will be automatically seated and sealed by the action of its return spring, while the inlet valve is urged immediately to its seated position and retained in such position over the inlet port, by the action of straps 28. Throughout the pumping and dispensing action as aforedescribed, lip seal 41 will automatically be flexed, upon inward displacement of the piston, by rib 49, with the result that each time a charge of flowable product is delivered through the outlet port to the atmosphere, a vent passage in open communication with the atmosphere is established through the clearance space between the seal 41 and the inner wall of cylinder 18. Thus, atmospheric air may be drawn into the container through vent port 48 as necessary to replenish dispensed product. Another embodiment of the liquid dispensing pump or trigger sprayer of the invention is generally indicated 10A in Figure 3 and is constructed in essenti­ ally the same manner as pump 10 except for the venting feature. Here, an annular lip seal 41 forming a vent valve is located sufficiently inwardly from rim 47 of the piston so as to cover vent port 48 at the end of the piston suction stroke. As in Figure 1, snap beads are provided on the piston and the inner wall of cylinder 18 for retaining the piston within the cylinder, except that in Figure 3 a vent passage 51 is defined outwardly of the lip seal between a skirt 52 on which the seal is formed and the inner surface of cylinder 18. Thus, when the seal uncovers vent port 48 in the discharge opening position, atmospheric air is drawn into the container through the open vent passage and the uncovered vent open­ ing. In Figure 4, a liquid dispensing pump generally designated 10B is similarly constructed as the afore­ described embodiments except for the valving feature. In addition, valving element 26 has an inner concentric sleeve 53 defining an annular space with the cylindrical wall of the valving element for the reception of the return spring 42 and having an inner cylindrical wall along which piston skirt 38 slidingly and sealingly engages. Valving element 26 is extended for engagement by means of its annular flange 54 with the outer end of cylinder 18 in the discharge closing position. This is a fluid tight engagement since valving element 26 also functions as a vent valve in this embodiment. The skirt 41 of the piston slides along the inner surface of the valving element in a fluid tight manner during the pumping operation. To facilitate venting, element 26 has a smaller outer diameter relative to the inner diameter of cylinder 18 between the vent valve and the outlet valve 34 so as to define an annulus 55. At least one axially extending groove 56 is provided in the wall of cylinder 18 between this annulus and flange 54. Thus, in the discharge open­ ing position, valve 34 shifts outwardly as in the other embodiments described above as does the outer annular wall of the valving element thereby causing flange 54 to shift outwardly to define an open vent passage from the atmosphere to the container via open groove 56, annulus 55 and the container vent which is now uncovered. A further embodiment of the invention is shown in Figure 5 as a liquid dispensing pump 10C which is essentially the same as that of Figure 1 except that the piston and valving member axes are parallel to the discharge passage 13 rather than extending at an angle between the inlet and discharge passages as before. Also, end wall 19 c of the pump body, end wall 27 c of valving element 26 c , and the piston head of piston 37 c are all flat and substantially parallel to one another, as shown, so as to lie perpendicular to the common axes of the cylinder, and the valving and piston elements. Otherwise, the operation of the pump is essentially the same as that described in detail with reference to Figure 1. While only a section of this dispensing pump 10C is shown, it should be noted that a portion of shroud 24 is sealed against the upper end of the passage which terminates in outlet port 22 so as to avoid leakage. Still another embodiment of the trigger sprayer according to the invention is generally designated 10D in Figure 6, and is similar to sprayer 10A of Figure 3 regarding the venting feature. However, unlike the foregoing embodiments, trigger sprayer 10D has a piston 37 d with no skirt of lip seal 38 so that the volume of pump chamber 39 is enlarged as product additionally fills the annular space between cylinder 18 and the piston. And, although valving element 26 is the same as that of the Figure 3 pump, only the inlet valve portion 31 thereof functions the same as in Figure 3. Otherwise, valving element 26 of Figure 6 has no accumulator function or effect. Flange 34 of the valving element seals against ring 33 under the force of spring 42 but cannot be dislodged from this sealing position contrary to the aforedescribed sprayers. Since the piston operates within cylinder 18 which functions as a pump cylinder, rather than within the valving element which functions as a pump cylinder in the foregoing embodiments, lip seal 36 of the valving element functions as a discharge valve in the Figure 6 embodiment in response to an increase in hydraulic pressure within the pump chamber during the compression stroke so as to flex radially inwardly away from the inner wall of cylinder 18 for opening the discharge, while remaining closed at all other times. Thus, by simply removing piston skirt 38, sprayer 10A of the pressure accumulating type is converted into a sprayer 10D of the throttling type in which lip seal 36 functions as a circular bunsen valve in the discharge path which opens from hydraulic pressure within the pumping bore during the piston compression stroke, and remains closed during the piston suction stroke. All other parts of the sprayer are thus interchangeable with the parts of sprayer 10A, although sprayer 10D has approximately double the spraying capacity compared to the other sprayers described above. Also, trigger level 43 is preferably longer to provide a higher strength for effecting an increased leverage and stroke. Although the venting feature of sprayer 10D is shown similar to that of sprayer 10A, the venting feature of the Figure 1 sprayer could be adopted without departing from the invention and if desired, the cylinder, valving element and piston of Fig. 6 could lie parallel to the discharge passage as in Fig. 5. Each of the trigger sprayer embodiments of the invention has shipping seals for the vent passage as well as for the inlet and outlet ports which are automatically self-closing when the pump is at rest and between dispensing strokes. And, each of the sprayers is adapted for fabrication from a minimum number of parts using a minimum number of assembly operations. As noted above, shroud 24 may be integrally fabricated with the remainder of the pump body. Also, a nozzle plug 20 can be simply inserted in place together with the trigger level, and nozzle cap 23 is snapped or threaded into place. Dip tube 14 is conventional, and the piston, valving element and return spring are capable of being assembled as a sub-assembly and inserted within the bore of cylinder 18. And, the cylindrical connecting portion of the pump body and the internally threaded closure cap may be permanently attached together as in the manner disclosed in U.S. patent 4,361,256. The quick opening and slow opening discharge valves described with reference to Figure 1 apply equally as well to the Figures 3, 4 and 5 embodiments. And, straps 28, which interconnect the inlet valve at the tip of wall 27 of the valving member and the base of this wall, shown in detail in Figure 2, are similarly arranged in the valving elements of the Figures 3, 4 and 6 embodiments, as well as in the Figure 5 embodiment except that wall 27 c is flat rather than conical therein. A central portion of this wall 27 c nevertheless functions as an inlet valve. And, straps 28 are neutral from a pressure standpoint and flange 34, together with annular groove 35, define an accumulation chamber of appreciably larger diameter than the pump chamber such that, as the compression force of the piston continues, there will be a progressively increasing fluid pressure within the accumulation chamber until such pressure creates an outward force in an axial direction causing the side wall of the valving element to shift outwardly relative to inlet valve 31 which remains seated during the influence of increased pressure within the pump chamber and against the inlet valve. The straps permit wall 27 or 27 c to flex and to resume its initial position during the discharge valve opening and closing operations. Although a plurality of such straps are illustrated, it should be pointed out that as few as two straps may be provided without department from the invention. Moreover, the straps may be shaped other than shown, so long as they are extendable between tip and base of wall 27 to facilitate relative axial shifting during the pumping operation as in the manner aforedescribed. And, by simply providing a piston number without a piston skirt 38, a sprayer of the pressure accumulating type can be easily converted into a sprayer of the throttle type having an increased pump capacity.

Claims: 1. A liquid dispensing pump which includes: a pump body (11) defining a pressure accumulation chamber (32) having an axially directed inlet port (21) for communication with a source of flowable product to be dispensed, and an outlet port (22) at the periphery of the said chamber; a unitary element (26) including an inlet check valve (31) controlling the said inlet port and further including an outlet valve (34) disposed for axial movement in said chamber from a closed position which it blocks communication between said ports (21, 22) to an open position in which is established communication between said ports; a pump cylinder (18) defining a pump chamber (39) coaxial with the said pressure accumu­ lation chamber and in open communication therewith; a pump piston (37) reciprocable in said cylinder independ­ ently of the movement of the said outlet valve (34); resilient means (42) normally urging the said outlet valve toward its closed position; and means (43) for manually reciprocating said piston; characterized in that: the said unitary element comprises a thimble-­ shaped element (26) having at its inner end a transverse end wall (27) including a central portion constituting the said inlet valve (31), the said wall being formed with a plurality of elongate openings (29) establishing the open communication between the said chambers (32, 39), and defining therebetween flexible straps (28) which facilitate relative axial shifting of the said inlet and outlet valves (31, 34) during a pumping opera­ tion. 2. A liquid dispensing pump according to claim 1, characterized in that the said resilient means comprises a coil spring (42) encircling the said piston (37) and compressed axially between the piston and the unitary element (26). 3. A liquid dispensing pump according to claim 1 or 2, characterized in that the pump body (11) includes mutually perpendicular inlet and outlet passages (12, 13) respectively terminating in said inlet and outlet ports (21, 22), the axis of said unitary element (26, 26c) and said piston (37, 37c) extending at an angle to both passages, or parallel with the outlet passage (13). 4. A liquid dispensing pump according to claim 1, 2 or 3, wherein the pump body (11) has a cylindrical wall including a vent passage (48) to establish communication between a container to which the pump is applied and the atmosphere, either the piston (37) or the unitary element (26) having a vent seal (41 or 54) in engagement with the cylindrical wall for opening and closing the vent passage. 5. A liquid dispensing pump according to any one of claims 1 to 4, characterized in that the said pressure accumulation chamber (32) is defined by the inner end of the said unitary element (26) and a confronting end wall (19) of the chamber, the said pump body including an annular ring (33), and the said unitary element (26) hav­ ing an annular groove (35) bounding said outlet valve in the form of an annular valve flange (34), the said unitary element being in sealing engagement with said pump body outwardly of the said outlet port (22), and the said valve flange (34) engaging only the said ring (33) in the closed position of the outlet valve so as to operate as a quick acting outlet valve. 6. A liquid dispensing pump according to any one of claims 1 to 4, characterized in that the said pressure accumulation chamber (32) is defined by the inner end of the said unitary element (26) and a confronting wall (19) of the chamber, and the said unitary element (26) has an annular groove (35) defining said outlet valve in the form of an annular valve flange (34), said pump body having a cylindrical wall containing said outlet port (22), the said valve flange (34) engaging the said cylindrical wall inwardly of the outlet port (22) in the closed position of the outlet valve and operating as a slow acting outlet valve.

Inventors: CORSETTE, DOUGLAS FRANK
Applicants: CORSETTE, DOUGLAS FRANK
Application year: 1985
Main classification: B05B11
IPC codes: F04B9, F04F1, B05B11