GB2029504A

GB2029504A - Manually operable sprayer

Info

Publication number: GB2029504A
Application number: GB7831829A
Authority: GB
Original assignee: ASL Airflow Ltd
Current assignee: ASL Airflow Ltd
Priority date: 1978-08-01
Filing date: 1978-08-01
Publication date: 1980-03-19
Also published as: GB2029504B

Abstract

A manually operable pump-action sprayer for discharging liquid under pressure from a container is constructed to enable liquid to be discharged continuously from a nozzle during pulling and release movement of a trigger. The sprayer has a trigger actuated pump plunger (5) and a spray head (1) comprising a first cylinder (2) and a second cylinder (11) defining a delivery passage (12) therebetween. The second cylinder (11) contains a spring-loaded piston (14) during the pump plunger delivery stroke the second cylinder (11) becomes filled with liquid as liquid simultaneously is delivered through the flow passage (12), and during the pump plunger suction stroke, piston (14) discharges liquid from cylinder (11) through the flow passage (12). <IMAGE>

Description

SPECIFICATION Manually operable sprayer This invention relates to manually operable pump-action sprayers for discharging liquid under pressure from containers. Sprayers of this kind are commonly used for dispensing insecticide, germicide, water, mineral oils and cleaning liquids. In whatever form, they commonly comprise a body detachably mounted on the liquid container, a dip tube, an inlet valve, a piston movable in a cylinder which leads to a spray head, an outlet valve and a spray nozzle in the spray head, a trigger movable relative to the body for moving the piston in one direction in the cylinder, and a spring for moving the piston in the reverse direction. All component parts with the exception of springs and pivot pins are commonly made of synthetic plastics material.

All these sprayers operate in the same fashion; that is to say when the trigger has been released, the spring moves the piston in a direction such as to create a partial vacuum in the cylinder thereby opening the inlet valve and causing liquid to be drawn up the dip tube into the cylinder. When the trigger is actuated again, the liquid is expelled from the piston chamber and as the inlet valve is now closed it moves through the outlet valve and thence to the spray nozzle. After some six to eight strokes the sprayer is primed, that is to say all the air therein has been expelled through the nozzle and the sprayer is full of liquid. The outlet valve stops air passing preferentially back into the spray head when the trigger is released.

The action of pulling the trigger creates a very high internal pressure in the spray head and as the liquid passes through the nozzle it escapes to atmosphere in a finely divided mist, the nozzle to this effect designed to impart rotation to the liquid which reaches it.

A characteristic of these sprayers is that liquid is only discharged from the nozzle when the trigger is being pulled and the object of the present invention is to anticipate or satisfy a demand for a manually operable pumpaction sprayer which can discharge liquid continuously from the nozzle that is to say during pulling and release movement of the trigger.

In accordance with the invention therefore a manually operable pump-action sprayer with a trigger-actuated pump plunger has a spray head comprising a first cylinder of which one open end communicates with a valve-controlled inlet for liquid under pressure whereas its other open end communicates with a spray nozzle, a second cylinder concentrically disposed within the first cylinder and spaced from it so as to form a passage for the flow of liquid from one end of the first cylinder to the other, the second cylinder being open at its end nearest the valve controlled inlet and containing a piston which is resiliently biased towards the open end of the second cylinder, the piston being movable against the resilient bias under the pressure of liquid generated by the pump plunger when the trigger is pulled whereby the second cylinder becomes filled with liquid as liquid simultaneously is delivered from end to end of the flow passage, whereafter, in response to a fall in liquid pressure as the plunger retracts when the trigger is released, the resilient bias restores the piston towards the open end of the second cylinder thereby displacing the liquid which is in the second cylinder outwardly into, and along, the flow passage.

Preferably the resilient bias is a coil compression spring which acts between the closed end of the second cylinder and the piston therein.

A particular and at present preferred embodiment of the invention-to be described by way of example-is illustrated in the accompanying drawing, which shows in longitudinal section a spray head attached to the upper part of a pump-action sprayer.

Referring now to the drawing, the spray head 1, which is made of plastics material, comprises a first, outer cylinder 2 which has an internally screw threaded open end 2a by which it is attached to the body 3 of a pump action sprayer which also comprises a trigger 4 pivotally mounted on the body 3 and adapted when pressed to move a plunger 5 in an upward direction against the action of a spring 6 to eject liquid by way of a spring operated non-return valve 7.

Attached to the leading end of the outer cylinder 2 is a hollow plug 8 which contains a non-return valve 9 and carries at its outward end an exit nozzle assembly 10.

Concentrically mounted within the outer cylinder 2 is an inner cylinder 11 which communicates at one end with the cylindrical passage 1 2 which exists between the cylinders 2 and 11 and which communicates with a central bore 1 3 leading to the valve 9 in the plug 8.

The cylinder 11 contains a piston 14 which is resiliently biased towards the open end of the cylinder 11 by a compression spring 1 5.

The mode of operation of the thus-equipped manually operable pump-action liquid sprayer device is as follows: When the trigger 4 is pulled, liquid passes through the non-return valve 7, as with a known conventional sprayer device, and thence into the cylinder 11 where the liquid pressure forces the piston 14 towards the closed end of the cylinder 11, thereby compressing the spring 1 5. During initial movement of the piston 14 and tensioning of the spring 1 5 some liquid passes along the space 1 2 into the plug 8, opens the valve 9 and emerges as a spray from the nozzle assembly 10.

When now the trigger 4 is released, the spring 1 5 re-asserts itself by pushing the piston 14 back towards the open end of the cylinder 11. Since this liquid cannot return through the valve 7 it is forced to travel into and through the passage 12 and thence through the nozzle assembly as it has already done when the trigger 4 was being pulled.

The above sequence of events continues for as long as the trigger 4 is continually pulled and released with the result that a spray is continually produced from the nozzle assembly.

The advantages of a continually produced spray in terms of rate of spray and consequential improvement of efficiency in the performance of spraying operations will be self evident.

Claims

1. A manually operable pump-action sprayer having a trigger-actuated pump plunger and a spray head comprising a first cylinder of which one open end communicates with a valve-controlled inlet for liquid under pressure whereas its other open end communicates with a spray nozzle, a second cylinder concentrically disposed within the first cylinder and spaced from it so as to form a passage for the flow of liquid from one end of the first cylinder to the other, the second cylinder being open at its end nearest the valve controlled inlet and containing a piston which is resiliently biassed towards the open end of the second cylinder, the piston being movable against the resilient bias under the pressure of liquid generated by the pump plunger when the trigger is pulled, whereby the second cylinder becomes filled with liquid as liquid simultaneously is delivered from end to end of the flow passage, whereafter, in response to a fall in liquid pressure as the plunger retracts when the trigger is released, the resilient bias restores the piston towards the open end of the second cylinder thereby displacing the liquid which is in the second cylinder outwardly into, and along, the flow passage.

2. A manually operable pump-action sprayer as claimed in claim 1 wherein the resilient bias is a coil compression spring which acts between the closed end of the second cylinder and the piston therein.

3. A manually operable pump-action sprayer constructed and adapted to operate substantially as herein described with reference to, and as shown in, the accompanying drawing.