IE56873B1 - Liquid dispensing pump - Google Patents

Description

This invention relates to manually actuated dispensing pumps.

U.Se patent 4,072,252 discloses such a pump, comprising a pump housing for mounting with a closure cap at the upper end of a container for fluent product, with the said pump housing extending transversely above the closure cap, the housing comprising a pump cylinder open at its outer end to atmosphere and providing at its inner end region a pump chamber for a manually reciprocable piston, the said cylinder having in its lower region a vent port positioned outwardly of the said chamber and in open communication with the interior of the container, the said piston having a vent seal for closing communication between the open end of the said body and the vent port.

In the arrangement disclosed in the U.S. Patent, the vent seal must repeatedly pass to-and-fro across the vent port and is thus liable to suffer attrition, resulting eventually in localized failure of the seal.

This means that not only will the efficiency of the pump be impaired but also that product will be able to escape past the damaged seal and run out of the open end of the cylinder body.

According to the present invention there is provided a manually actuated dispensing pump, comprising a pump housing for mounting with a closure cap at the upper end of a container for fluent product, with the said pump housing extending transversely above the closure cap, the housing comprising a pump cylinder open at its outer end to atmosphere and providing at its inner end region a pump chamber for a manually reciprocable piston, the said cylinder having in its lower region a vent port positioned outwardly of the said chamber and in open communication with the interior of the container, the said piston having a vent seal for closing communication between the open end of the said « body and the vent port, the said vent seal being positioned outwardly of the vent port in all operative t positions of the pump piston and sealingly engaging the * 5 interior of the cylindrical body in the outermost nonpumping position of the piston and the said body being formed in the upper region of its inner surface with means to permit the passage of air past the vent seal from the open end of the said body to the vent port, IQ during an inward, pumping stroke of the piston.

With this arrangement, the danger of attrition of the vent seal by passage across the vent port is obviated.

Further features and advantages of the invention 15 will appear from the following detailed description, given by way of example of some embodiments thereof, which are illustrated in the accompanying drawings, in which: Figure 1 is a vertical sectional view of a 20 dispensing pump according to one embodiment of the invention; Figures IA and IB are sectional views similar fo Figure 1 showing details of quick opening and slow opening discharge valves, respectively; Figure 2 is a perspective view of the thimble® shaped member according to Figure 1; and Figure 3 is a sectional view similar to Figure 1 of another embodiment according fo the invention, with & portions only of the pump being shown.

Turning now to the drawings wherein like reference characters refer to like and corresponding parts throughout the several views, a liquid dispensing in the form of a trigger operated sprayer is, according to one embodiment of the invention, generally designated 10 in Figure 1 which includes a ’ pump body 11 defining an inlet passage 12 and an outlet passage J 13. A conventional dip tube 14 is received within the inlet passage and extends into a container (not shown) of product to be dispensing in a manner well known in the art. Λ container It) 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 onto the neck of the container, and if desired a seal ring 17 may be disposed between the lower end of pump body and the upper end of the container neck.

The pump body further includes a 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 φ cap 23 in engagement with the plug. Also, the pump body is provided with an integral shroud 24, which may otherwise be * made separately and assembled in place and having a contoured § wall 25 shaped to Cit 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 view Figure IA, is defined between the inner end of element 26 and the confronting surfaces of the 20 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 «S an annular flange 34 on element 26 adjacent 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. Ί A pump piston 37 in the form of a thimble or cup-shaped J element extends into valving element 26 and has a flexible, circular p 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 element 37 surrounds the open end thereof and is elideable 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.

Cooperating 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 reciprocation 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 thereof a sufficient distance 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 operation.

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 such 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 container 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 piston element 37, are all avoided.

In operation, after the pump chamber is primer] 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 increaee the pressure within the pump chamber which maintains inlet 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 discharge 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 actuating force on the piston or through approach of the piston to the end of its pressure stroke, so as to produce insufficient force to overcome the return spring, the spring will act to return the outlet valve immediate]γ I o its closed position, thereby affording an abrupt sharp cutoff of the discharge to minimize dripping of product from the discharge nozzle.

Since the discharge valve (or flange) 34 trakes tangential contact (Fig. IA) with ring 33, and the outer surface of the discharge valve is radially inwardly spaced from the wail 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 IB wherein a flange (or outlet valve) 31a 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 34a 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, thereby enabling a charge of flowable product from the container 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 ΰ the outlet valve will be automatically seated and sealed by the action of its return spring, while the inlet valve is urged y immediately to its seated position and retained in such i 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 Ilexed upon inward displacement of the piston, by rib 49, with (.lie 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.

It will be noted that the vent seal 41 is positioned outwardly of the vent port 48 in alL operative positions of the pump piston, so that it does not pass across the vent port at any time. <4 * A further embodiment of the invention is shown 5 in Figure 3 as a liquid dispensing pump IOC 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 19c: of the pump body, end wall 27£ of valving element 26£, and the piston head of piston 37£ are all flat and substantially parallel to one another, as shown, so as to lie perpendicular to the concentric axes qf 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.

V Each of the trigger sprayer embodiments of the I invention has shipping seals for the vent passage as well as for the inlet and discharge 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 lever, 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.

I; The quick opening and slow opening discharge valves described with reference to Figure 1 apply equally as well to it the Figure 3 embodiment. The straps 28, which t interconnect the inlet valve at the tip of wall 27 of the valving member and the base o£ thia wall, shown in detail in Figure 2, are similarly arranged in the valving elements of the Figure 3 embodiment except 5 that wail 27c ia flat rather than conical * therein, A centra! portion of this wall 27c 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 tho 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 tbe 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 27e to t 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 fsv as two straps may be provided without departing item the invention. Hereevee, the straps may be shaped ether than shewn/ se leng as they are extendable between tip and base et wall 27 te facilitate relative axial shifting during the puiiipbiy eperat 1 on as in the manner afotedesoribed.

And, by simply providing a piston member 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 (8)

1. CLAIMS;

1. A manually actuated dispensing pump, comprising a pump housing for mounting with a closure cap at the upper end of a container for fluent product, with the said pump housing extending transversely above the closure cap, the housing comprising a pump cylinder open at its outer end to atmosphere and providing at its inner end region a pump chamber for a manually reciprocable piston, the said cylinder having in its lower region a vent port positioned outwardly of the said chamber and in open communication with the interior of the container, the said piston having a vent seal for closing communication between the open end of the said body and the vent port, the said vent seal being positioned outwardly of the vent port in all operative positions of the pump piston and sealingly engaging the* interior of the cylindrical body in the outermost non- : pumping position of the piston and the said body being formed in the upper region of its inner surface with means to permit the passage of air past the vent seal from the open end of the said body to the vent port, during an inward, pumping stroke of the piston.

2. A pump according to Claim 1, wherein the said cylinder comprises a counterbore outwardly of the said pump chamber, the said vent seal engaging the interior of the counterbore.

3. A pump according to Claim 1 or 2, wherein the said cylindrical body is disposed at an angle to the axis of the container, with the inner end of the body higher than the outer end when the container axis is vertical.

4. A pump according to Claim 1, 2 or 3, wherein the said vent seal comprises a resiliently flexible lip seal. 1 6

5. Ά pump according to any- preceding claim, wherein the said means comprises an axial directed rib formed on the inner surface of the said cylindrical body. .

6. A pump according to any one of Claims 1 to 5, 5 wherein the said housing includes a thimble-shaped Γ unitary element defining the said pump chamber and a pressure accumulation chamber, with said element, in open communication with the said pump chamber, the element having an inner end containing inlet and outlet 10 check valves for controlling an inlet and an outlet for fluent product.

7. A pump according to Claim 6, wherein the inner end of the unitary element includes a wall comprising a plurality of straps lying between said valves and 15 defined by openings establishing open communication I between the said chambers, the said straps being flexible to permit relative axial shifting of the said valves in the pumping position.

8. A manually actuated dispensing pump according to 20 Claim 1, substantially as hereinbefore described with particular reference to and as illustrated in the accompanying drawings.