MXPA00001094A - Liquid dispensing pump - Google Patents

Abstract

A manually actuated dispensing pump has a pump housing (10) for mounting with a closure cap (11) at an upper end of a container for fluent product, the housing having a pump cylinder (12) open at its outer end to atmosphere and providing at its inner end area a pump chamber (13) for a manually reciprocable piston (14) having a resilient piston seal (21). The cylinder has in its lower area at least one vent port (17) positioned outwardly of the pump chamber, the piston having a vent seal (19) for closing communication between the open end of said cylinder and the vent port. The piston forms a sub-assembly with the housing upon insertion into said cylinder (12) through the open outer end thereof, and one or more ramps (29) or tapered ribs are provided adjacent the vent port (17) for spacing the piston seal (21) from an inner edge of the vent port permitting the piston seal to by-pass the vent port to avoid any damage of the piston seal upon assembly into the cylinder.

Description

LIQUID DISTRIBUTING PUMP BACKGROUND OF THE INVENTION This invention relates generally to a trigger-operated pump jet having an alternating pump piston within a pump cylinder, the piston having an internal piston seal and an external vent seal. The outer end of the cylinder provides a pump chamber, and the cylinder has in its lower region a ventilation port positioned outwardly of the pump chamber and in open communication with the interior of the container to which the spout is mounted. The vent seal closes the communication between the open end of the cylinder and the atmosphere, and the vent seal is placed out of the vent port in all operative positions of the pump piston. The means on the inner surface of the cylinder allow the passage to deflect the vent seal from the open end of the cylinder to the ventilation port during a pumping stroke into the piston. Since the piston seal (sometimes referred to as a power inlet) and the vent seal (or ventilation vent) is placed on both sides of the vent port in all operating positions for the pump piston, the piston will It is assembled first inside the hole it must have its piston seal transverse to the ventilation port. During this assembly process, the piston seal often becomes enmeshed as it slides on the inside edge of the vent port. Such damage, even if minor, is known to affect the hermetic seal between the piston seal and the wall of the pump cylinder. This sealing brake causes undesirable spillage of the product from the pump chamber which is under pressure during the working stroke of the piston. Such pressurized liquid is blown by the piston seal and into the annular vent chamber formed between the piston seal and the vent seal. And during the working stroke in the piston that causes the fluid to escape from the pump chamber to the container by means of the ventilation chamber and the ventilation port. In the next return stroke, the damaged power projection will be admitted as undesirable air into the pump chamber by means of the ventilation chamber which is briefly opened to the atmosphere. This reduces the ability of the pump to suck a sufficient amount of fluid into the pump chamber resulting in the pump chamber filled with a mixture of liquid and air. The continuous pumping therefore results in a sparse spray pattern with emission of liquid air through the nozzle orifice. Also, if the power output is damaged during the initial assembly, the number of strokes required to start the pump increment, and depending on the exception of the damage to the power output, may not be fully initialized.

If the damage to the energy protrusion is small so that the pump can be initialized, then the output during each piston stroke will be less than expected as the liquid escapes from the power release and returns to the vessel through the chamber. ventilation and ventilation port. The piston seal may be in the form of a protruding seal that curves slightly inward at its inner peripheral edge, so that the outer wall surface of the protrusion sealingly engages the confronting wall surface of the protruding chamber. bomb. It is that outer surface that frequently has surface scratches during the piston assembly within the cylinder bore. Otherwise the piston seal can be structured obtaining a sharp edge protrusion seal so that the protrusion engages the wall of the pump chamber at the end peripheral edge thereof. This design facilitates a more complete scraping of the pump chamber wall during alternating piston to keep that wall surface completely free of any buildup of any undesirable film layer or partially dried condensed particles of the product. The pump projection cleans the pump chamber wall during the piston alternation so as to improve the sealing capability between the pump seal and the pump chamber wall chamber at all times.

This last style of pump protrusion is even more prone to damage due to the interference of the protrusion while passing over the ventilation port on the piston assembly. Since the peripheral edge of the protruding seal establishes the hermetic liquid seal with the pump chamber even small scrapes or scratches of the protrusion on the peripheral edge could break the seal with the pump chamber wall and thus cause leakage of liquid.

BRIEF DESCRIPTION OF THE INVENTION It is therefore an object of the present invention to provide a manually operated pump jet with its pump cylinder structured to avoid the aforementioned problems, in a highly effective yet simple and economical way. The object of the invention is achieved by the provision of means on the wall of the pump cylinder adjacent to the pump port to separate the piston seal from the inner edge of the ventilation port so that the piston seal deflects the ventilation port to avoid any abrasion of the piston seal to the insertion of the piston inside the pump cylinder during the assembly process. Such means for separating the piston seal from the inner edge of the vent port on the piston assembly comprise at least one tapered rib on one side of the vent port, although a pair of tapered ribs may be provided on opposite sides of the port of the vent. Ventilation if desired. In the case of two lateral ventilation ports a tapered rib can be provided to divide the two ports. Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the invention when taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a. side elevational view, partially separated, of a trigger pump pump jet embodying the invention; Figure 2 is a partially separated perspective view of a pump piston composition and pump cylinder of the prior art, before the piston is inserted into the cylinder during assembly; (TA) = Prior Art Figure 3 is a sectional view showing part of a type of piston seal relative to a cylinder bore; Figure 4 is a view similar to Figure 3 of another type of piston seal; Figure 5 is a view similar to Figure 2 of the piston cylinder embodying the present invention; Figure 6 is an elongated sectional view taken substantially along line 6-6 of Figure 5; Figure 7 is a cross-sectional view of the pump cylinder embodying the invention and a part of the piston seal showing how to avoid contact with the ventilation port during the assembly of the piston within its orifice; Figure 8 is a view similar to Figure 5 of another embodiment of the invention; and Figure 9 is a view similar to Figure 8 of yet another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Returning to the drawings in which similar reference numbers refer to similar and corresponding parts through the different views, Figure 1 illustrates a trigger-operated sprinkler including a rubber housing 10 having a limb member. closure 11 for facilitating the mounting of the trigger sprinkler to the neck of a container (not shown) of the liquid product to be dispensed. The pump housing has a pump cylinder 12 open at its outer end towards the atmosphere and which provides in its internal end region a pump chamber 13 for a manually alternating pump piston 14. The piston is reciprocable in and towards outside the hole of its cylinder to the manual operation of the trigger lever 15 mounted hinged to the housing of pump to move the piston inwards during its piston stroke. A piston return spring 16 elastically urges the piston out of its cylinder bore during its piston return stroke to the relaxation of the force applied by the operator of the trigger lever. The pump cylinder 12 has in its lower region a ventilation port 17 placed out of the pump chamber 13 and in open communication with the interior of the container by means of a ventilation passage 18. The structural relationship described above is essentially explained in the North American patents 4, 618,077 and 5,114,049. The piston has an annular vent seal 19, or salient seal as it is sometimes called, to close the communication between the open end of the cylinder and the vent port. That piston likewise has an internal piston seal 21, or protrusion seal, separate from the ventilation seal and defining therewith an annular ventilation chamber 22. The ventilation seal 19 is positioned outwardly of the ventilation port 17 in all the operative positions of the pump piston and sealingly engaging the inside of the pump chamber 13 in the position without outermost pumping of the piston as shown in Figure 1. The cylinder comprises an enlarged orifice 23 outwardly of the internal portion of the cylinder bore defining the pump chamber, and the ventilation seal 19 engages the interior of the enlarged bore. The enlarged orifice 23 of the pump cylinder is formed on its inner surface with a longitudinal rib or ribs 24 to allow the passage of air through the vent seal from the open end of the cylinder to the ventilation port, during a pumping stroke to inside the piston. As shown, the vent port 17 is located in a transaction area 25 between the orifice and the enlarged orifice area 25 that slopes outwardly as shown. At the initial insertion of the pump piston into its cylinder bore in the direction of the arrow of Figure 2, the piston seal 21 first slides along the enlarged bore and upon reaching the transition area 25 is constrained about from its periphery until it seals tightly and sealingly the wall of the cylinder bore that defines the pump chamber. During this process, the piston seal passes through the ventilation port, which at its inner end defines a tapered edge 26 (Figure 6). The piston seal may be of the type shown in Figure 3 at 21A in which the terminal end 27 does not engage the wall of the cylinder bore, but rather the end portion of the piston seal is folded inwardly so that contact is made with the cylinder bore by the external curved surface of the piston seal as shown. Therefore, during the assembly process this curved surface moves across the edge 26 of the ventilation port and is often enmeshed or scratched superficially during assembly. The piston seal when in its fully assembled position of Figure 1 can not therefore sealingly engage the wall of the cylinder bore with either side of reliability because it has been damaged, albeit slightly, during the process of assemble This rupture compromises the sealing action required between the piston seal and the cylinder bore. Another style of piston seal is shown in Figure 4 at 21B in which the outer peripheral edge 28 of the seal couples the cylinder bore so that during the assembly process this peripheral edge is known to be damaged due to seal interference piston with the inner edge 26 of the ventilation port. The peripheral edge is defined by the intersection of the outer surface 31 and the terminal end surface 32 of the nozzle seal. The piston seal is designed to have a sharp edge to clean the surface of the cylinder bore during piston strokes, thereby preventing the accumulation of any film or residue that would otherwise compromise the sealing action required between the piston seal and cylinder bore. According to the invention ramps 29 are provided in the transition area 25 adjacent to the ventilation port. If two ramps are provided they may be located on opposite sides of the ventilation port. If a single ramp is provided it can be located on one or on the other side of the ventilation port in the immediate vicinity. The ramp or ramps are inclined as shown clearly in Figure 6 to separate the piston seal 21A21B of the internal sharp edge 26 of the ventilation port as in the elastic piston seal 21 is temporarily distorted as shown in Figure 7 during the process of forming a sub-assembly with the pump housing to the insertion of the pump piston within of the cylinder through the open external end thereof. When the piston seal reaches the cylinder cylinder bore of the cylinder it returns to its initial undistorted condition and hermetically couples the orifice wall to seal the liquid in the pump chamber against spillage. If a pair of side-by-side ventilation ports 17 is provided in the inclined transition area 25 as shown in the embodiment of Figure 8, the inclined ramps 29 can be located on external sides of the pair and an intermediate ramp 31 can be provided. between the external ramps to ensure the total free space between the power projections 21A, 21B and the internal edges of the ventilation ports to the assembly. The arrangement of ramps 29, 31 can also be provided for an individual elongated vent port instead of the pair from side to side shown. The invention is not limited to incorporation into a pump cylinder having a widened orifice or hole in which the port or ventilation ports are located in an inclined transition area. The cylinder may otherwise have a vertical hole as shown in Figure 9 with the port or vent ports 17 that are located outwardly of the pump cylinder 13 as in Figure 1. During the assembly process, the curved edge external seal of the piston seal 21A, or sharp edge 28 of the piston seal 21B are temporarily raised in housing from the ventilation port and its internal sharp edge to deflect the port or ventilation ports thus avoiding any abrasion or grated surface seal of piston that could later affect the performance of the sprinkler. According to the invention, the integrity of the piston seal is retained after being assembled with the pump housing and the tendency for the pump chamber to spill during pumping is minimized as the piston seal prevents abrasion due to the piston seal. to the interference with the ventilation port to the installation. Also, by preserving the integrity of the power projection, the reliability of the pump initiation is improved, and the quality of the spray during pumping is also improved. The provision of one or more tapering ribs or ramps on one or both sides of the vent port to temporarily raise a portion of the vent seal away from the transition area during the assembly process to thereby separate that peripheral portion of the seal piston away from the ventilation port and its sharp internal edge, avoids the enmeshing or superficial grating or some other form of abrasion due to grating against the sharp edge as in the prior art. The ramps are simply molded in place during the pump housing molding process. This approach taken in accordance with the invention solves the problems noted for the prior art sprinklers and is economical and not complicated and highly effective. Obviously many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is understood that within the scope of the appended claims, the invention can be practiced in a manner other than that specifically described.

Claims (10)

1. A manually operated dispensing pump, characterized in that it comprises a pump housing for mounting with a closure cap on an upper end of a container for fluid product, the housing comprising a pump cylinder open at its outer end towards the atmosphere and providing in its internal end area a pump chamber for a manually alternating piston having an elastic piston seal, the cylinder having its lower area at least one ventilation port positioned out of the chamber, the piston having a seal of ventilation to close the communication between the open end of the cylinder and the ventilation port, the piston that forms a subassembly with the housing to the insert inside the cylinder through the open external end thereof, the improvement where the cylinder has about its internal surface means adjacent to such vent port to separate the piston seal from a inner edge of vent port that allows the piston seal to bypass the vent port to avoid any damage to the piston seal assembly inside the cylinder.

2. The pump according to claim 1, characterized in that the cylinder comprises a bore enlarged outwardly of the pump chamber, the ventilation seal that couples the inside of the enlarged orifice, a transition between the chamber and the enlarged orifice defining a ramp. annular, the ventilation port that is located on the ramp.

3. The pump according to claim 1, characterized in that the ventilation seal comprises a flexible nozzle seal having a peripheral edge in sealing engagement with an internal surface of the pump chamber, the peripheral edge which is defined by the intersection of the extreme external and terminal surfaces of the nozzle seal.

4. The pump according to claim 1, characterized in that the cylinder comprises a hole of substantially constant diameter.

5. The pump according to claim 1, characterized in that the separating fears comprise at least one tapered rib on one side of the ventilation port.

6. The pump according to claim 1, characterized in that the separation means comprise a pair of tapered ribs on opposite sides of the ventilation port.

7. The pump according to claim 2, characterized in that the separating means comprise at least one tapered rib on the annular ramp on one side of the ventilation port.

8. The pump according to claim 2, characterized in that the separation means comprise at least one pair of tapered ribs on the annular ramp on opposite sides of the ventilation port.

9. The pump according to claim 7, characterized in that the separating means further comprise an intermediate tapered rib in the annular ramp between the pair of ribs.

10. The pump according to claim 2, characterized in that a pair of side ventilation ports are provided on the ramp, the separating means comprising a pair of tapered ribs and an intermediate rib between them on the ramp in immediate vicinity of the ports of ventilation.