GB2085972A - Improvements in pressure- operated sprayers - Google Patents

Abstract

In a pressure-operated sprayer a manually-operated pump (3) for pressurising the contents of a container (1) comprises a cylindrical body (4) extending into the container (1) and in the bore of which works a piston (8) carried by a hollow piston-rod (9) by means of which the container (1) can be pressurised through oppositely acting first and second one-way valves. The first valve comprises a sealing ring (22) housed within a radial groove (23) and the body (4) defines a dip-tube through which pressurised liquid can be dispensed from the container and through the hollow piston-rod (9). When the piston (8) has been locked in a fully depressed position by the opening of second and third valves (20; 14, 15), which are connected by rod 16. The second and third valves being actuable by means of button 18. <IMAGE>

Description

SPECIFICATION Improvements in pressure-operated sprayers This invention relates to pressure-operated sprayers of the kind comprising a container for liquid, a manually-operable pump for pressurising the contents of the container, and a manually-operable valve for controlling the dispensing of pressurised liquid from the container.

In known sprayers of the kind set forth the pump is detachably mounted on a neck at the upper end of the container, and the liquid is dispensed from the container through a connection in the wall of the container separate from the pump and connected to a flexible pipe leading to a lance or other appliance through which the liquid is dispensed from the container under the control of the valve which may be embodied in the lance. Alternatively the liquid may be conveyed to an outlet nozzle through a valve and through a dip-tube which projects into the liquid from the body of the pump.

According to our inventon in a pressureoperated sprayer of the kind set forth the pump comprises a cylindrical body extending into the container for a substantial distance and in the bore of which works a piston carried by a hollow piston-rod and by means of which the container can be pressurised through oppositely acting first and second one-way valves located in the piston and in the body respectivley, the first one-way valve comprising a sealing ring of elastomeric material housed within a radial groove in the piston and of which the thickness is greater than the diameter of a section through the ring, and the body defining a dip-tube through which pressurised liquid can be dispensed from the container and through the hollow piston-rod, communication between the container and the piston-rod normally being prevented by automatic closure of the second one-way valve and a normally closed third valve incorporated in the piston and adapted to be opened to cause the second valve to open after the piston has been locked in a fully advanced position in which the sealing ring forms a seal between the body and the upper face of the groove, and he pump incorporates a member for operating the second and third valves in tandem to control the dispensing of liquid through the dip tube and the hollow piston rod.

By utilising the body of the pump as the dip-tube simplifies the construction and facilitates manufacture and assembly.

The upper end of the hollow piston-rod may lead to a nozzle projecting laterally from the upper end of the pump or to a flexible pipe leading to a nozzle or other similar appliance.

Preferably the upper end of the piston-rod is provided with a pair of diametral projections adapted to be inserted through complementary notches on a radial flange at the upper end of the body of pump, subsequent rotation of the piston-rod relative to the body acting to lock the piston in the fully advanced position with the lugs located against relative axial movement by the radial flange.

The member for operating the second and third valves may comprise a rod which extends axially through the piston rod, the rod carrying at its lower end a valve member for engagement with a seating in the piston and defining the third valve and at its upper end being provided with a thumb-piece by means of which the valves can be operated continuously or intermittently by the thumb of the user, the hand of which is conveniently carrying the sprayer, either by grasping an enlargement or other handle at the upper end of the piston-rod.

The upper end of the body may be integral with an adaptor having an internally screwthreaded skirt by means of which the body can be screwed onto the screw-threaded neck of the container.

Two embodiments of our invention are illustrated in the accompanying drawings in which: Figure 1 is a longitudinal section through a sprayer; and Figure 2 is a longitudinal section through the upper end portion of another sprayer.

The sprayer illustrated in Fig. 1 of the drawings comprises a container 1 for liquid which has externally screw-threaded neck 2 at its upper end, and a pump 3 for pressurising the liquid in the container 1.

The pump 3 comprises a cylindrical body 4 which depends from an adaptor 5 having an internally screw-threaded skirt 6 by means of which the pump 3 can be connected to the container 1 with the skirt 6 screwed onto the neck 2. In this position the body 4 extends longitudinally into the container 1 for a substantial distance. A hollow piston-rod 7 carries a piston 8 which works in the bore 9 of the body 4. The rod 7 is also guided in the bore 9 by ribs 10 on the rod 7. The ribs extend between the piston 8 and a pair of diametral lugs 11 at the upper end of the piston-rod 7 below a terminal annular wall 1 2 which surrounds a central portion 1 3 having a bore which is continuous with the bore of the piston-rod 7.

The lower end of the piston-rod 7 is closed by a valve (third valve) which comprises a head 1 4 which is engageable with a seating 1 5 on the innermost face of the piston 8. The head 14 is carried by the lower end of a rod 1 6 of which the upper end carries a piston 1 7 working in the bore of the central portion 1 3 and upon which is mounted a thumb-piece 1 8 housed within the wall 1 2. Inward movement of the thumb-piece 1 8 is operative to urge the head 1 4 away from its seating 1 5 to place the interior of the body 4 in communication with a radial nozzle 1 9 which extends outwardly through the wall 1 2 and is in communication at its inner end with the bore at the upper end of the piston-rod 7.

Communication between the interior of the body 4 and the container 1 is controlled by a spring-loaded one-way valve 20 (second valve) which is located in the base of the body 4, between the body 4 and a flexible tube 21 having an enlarged end which terminates close to the base of the container.

The piston 8 carries an '0' ring seal 22 of elastomeric material which is received in a groove 23 of which the axial length is greater than the diameter of a section through the seal 22, and a portion of the piston 8 which terminates at its free end is reduced in diameter to a diameter less than that of a shoulder 24 at the inner end of the body 4.

In operation, in the position shown in the drawings, the valves 14 and 20 are closed.

Reciprocation of the piston 8 in the bore of the body 4 is operative to pump air into the container 1 through the valve 20 and the tube 21. The valve 20 opens upon movement of the piston 8 in an inward directon but closes when the piston 8 is moved outwardly with air at atmospheric pressure entering a pump space 25 below the piston 8 through a clearance between the seal 22 and the wall of the body 4 with the seal 22 sealing between the piston 8 and the wall of the body 4 as the piston 8 is forced inwardly to pressurise the air in the pump space 25. The engagement of the seal 22 with the piston 8 and the body 4 defines a one-way valve (the first valve).

During reciprocation of the piston 8 in the body 4 inward movement of the piston 8 is limited by the engagement of the lugs 11 with a radial flange 26 at the upper end of the adaptor 5 which prevents the seal 22 from engaging with the shoulder 24 and the piston 8 from engaging with the valve 20.

After the container 1 has been pressurised the piston 8 is locked in a fully advanced position. This is achieved by a bayonet coupling between the piston-rod 7 and the adaptor 5 defined by the engagement of the lugs 11 in complementary diametral recesses 27 in the flange 26, whereafter the piston-rod 7 is rotated to cause the lugs 11 to engage with the undersurface of the flange 26. In this position the seal 22 is clamped against the shoulder 24 to seal the interior of the body 4 from atmosphere and the head 14 is disposed in close proximity to the valve 20.

Initial depression of the thumb piece 1 8 urges the head 14 away from the seating 1 5 and subsequent movement causes the head 14 to engage with and open the valve 20.

Thus the second and third valves are operated in tandem, preferably substantially simultaneously. This permits liquid under pressure to pass to the nozzle 1 9 through the pump space 25, and the hollow piston-rod 7. The supply con be continuous, or intermittent, depending upon manipulation of the thumb piece 8.

In the sprayer of Fig. 2 the container 1 comprises a can of the type forming the subject of our co-pending Patent Application of even date, and the wall 1 2 is modified to form an elongate handle 28 of generally channel section to facilitate carrying the sprayer. The nozzle 1 9 is adapted for connection to a flexible pipe 30, to the outer end of which is connected a lance or similar appliance.

The construction and operation of the sprayer of Fig. 2 is otherwise the same as that of Fig. 1 and corresponding reference numerals have been applied to corresponding parts.

Claims (9)

1. A pressure-operated sprayer of the kind set forth in which the pump comprises a cylindrical body extending into the container for a substantial distance and in the bore of which works a piston carried by a hollow piston-rod and by means of which the container can be pressurised through oppositely acting first and second one-way valves located in the piston and in the body respectivley, the first one-way valve comprising a sealing ring of elastomeric material housed within a radial groove in the piston and of which the thickness is greater than the diameter of a section through the ring, and the body defining a diptube through which pressurised liquid can be dispensed from the container and through the hollow piston-rod, communication between the container and the piston-rod normally being prevented by automatic closure of the second one-way valve and a normally closed third valve incorporated in the piston and adapted to be opened to cause the second valve to open after the piston has been locked in a fully advanced position in which the sealing ring forms a seal between the body and the upper face of the groove, and the pump incorporates a member for operating the second and third valves in tandem to control the dispensing of liquid through the dip tube and the hollow piston rod.

2. A sprayer as claimed in Claim 1, in which the upper end of the hollow piston-rod leads to a nozzle projecting laterally from the upper end of the pump.

3. A sprayer as claimed in Claim 1, in which the upper end of the hollow piston-rod leads to a flexible pipe leading to a nozzle or other similar appliance.

4. A sprayer as claimed in any preceding claim, in which the upper end of the pistonrod is provided with a pair of diametral projections adapted to be inserted through complementary notches in a radial flange at the upper end of the body of the pump, subsequent rotation of the piston-rod relative to the body acting to lock the piston in the fully advanced position with the lugs located against relative axial movement by the radial flange.

5. A sprayer as claimed in any preceding claim in which the member for operating the second and third valves comprises a rod which extends axially through the piston rod, the rod carrying at its lower end a valve member for engagement with a seating in the piston and defining the third valve and at its upper end being provided with a thumb-piece by means of which the valves can be operated by the thumb of the user.

6. A sprayer as claimed in Claim 5, in which an enlargement or other handle is provided at the upper end of the piston-rod by means of which the sprayer can be carried by a hand, the thunb of which can operate the thumb pice.

7. A sprayer as claimed in any preceding claim in which the upper end of the body is integral with an adaptor having an internally screw-threaded skirt by means of which the body can be screwed onto the screw-threaded neck of the container.

8. A pressure-operated sprayer substantially as described herein with reference to Figure 1 of the accompanying drawings.

9. A pressure-operated sprayer substantially as described herein with reference to Fig. 2 of the accompanying drawings.