GB2318782A

GB2318782A - Metered dispensing device

Info

Publication number: GB2318782A
Application number: GB9622449A
Authority: GB
Inventors: Alan Roger Harper
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-10-29
Filing date: 1996-10-29
Publication date: 1998-05-06
Anticipated expiration: 2016-10-29
Also published as: GB9622449D0; GB2318782B

Abstract

A dispensing device comprising: a container 11 for solvent defining an operating level 14 for solvent retained in the container; a vessel 15 located within the container below the operating level, the vessel providing a working volume 16 having an inlet 17, a port 28 and an outlet 19; the inlet 17 lying in a flow path between the container and the working volume including a valve 20 adapted to resist a flow of liquid out of the vessel by means of the inlet while allowing a flow of liquid into the vessel by way of the inlet; the port 28 linking the working volume by means of a duct 32 to a first location outside the vessel and above the operating level; the duct being pressurisable by way of the first location to increase pressure in the working volume; and the outlet 19 linking the working volume by means of a delivery pipe 33 to a second location outside the vessel and above the operating level, such that a metered dose is dispensed from the vessel. Typically the delivery pipe extends through the port. The container is conveniently provided with an aperture whereby solvent can be added to the container and the aperture closed by means of a demountable closure which can serve to support duct and/or the delivery pipe.

Description

DISPENSING DEVICE This invention relates to a dispensing device. It is particularly, but not exclusively, concerned with such a device for use in dispensing a predetermined amount of liquid for a subsequent operation.

In industries where use is made of liquid polymers there frequently arises a need to flush a mixing head of a mixing machine with a solvent. This is particularly in a production process where a sequence of moulds are filled in turn in the sequence by means of a mixing machine head. It is essential that the machine head is flushed out at following a mould filling to ensure that residual polymer containing accelerator is not left in the head with subsequent polymerisation leading to blockage. There are currently two systems widely used to deliver a volume of pressurised solvent to a mixing head. The first involves the use of a pressurised solvent pot with an outlet control valve which is periodically operated to release a controlled volume of solvent from the pot and into the head. The second involves the use of a reciprocating air driven pump. Both are relatively expensive involving the need for a pressure vessel, a pressurising means and seals across a working interface with which to retain the contained solvent.

According to the present invention there is provided a dispensing device comprising: a container for solvent defining an operating level for solvent retained in the container;; a vessel located within the container below the operating level, the chamber providing a working volume having an inlet, a port and an outlet; the inlet lying in a flow path between the container and the working volume including a valve adapted to resist a flow of liquid out of the working volume by means of the inlet while allowing a flow of liquid into the working volume by way of the inlet; the port linking the working volume by means of a duct to a first location outside the vessel and above the operating level; the duct being pressurisable by way of the first location to increase pressure in the working volume; and the outlet linking the working volume by means of a delivery pipe to a second location outside the vessel and above the operating level.

Typically the delivery pipe extends through the port.

According to a first preferred version of the present invention the container is provided with an aperture whereby solvent can be added to the container and the aperture is closed by means of a demountable closure. Typically the closure serves to support duct and/or the delivery pipe.

An exemplary embodiment of the invention will now be described with reference to the accompanying drawing of a dispensing device which the sole figure is a sectioned elevation.

The drawing shows a dispensing device 11 including a circular section container 12 for liquid solvent closed by a lid 13. The container 12 serves to hold liquid solvent to depth D to provide an operating level 14.

Vessel 15, of circular cross section, provides a working volume 16 located beneath the operating level 14. The working volume 16 is effectively closed save for three opening or passages: an inlet 17, a port 18 and an outlet 19.

The inlet 17 lies in a flow path defined by a tube 20 between an opening 21 (covered by a mesh filter 22) into the lower part of the container 12 and the working volume 16 by way of slots 23. The tube 20 contains an annular valve seat 24 on which valve 25 resiliently loaded by spring 26 can seat to close the flow path. The vessel 15 is provided with legs 27 to maintain the opening 21 clear of any debris lying on the bottom of container 12.

The port 18 is coupled by duct 28 to a first location 29 where the duct 28 has an end closure 30. An inlet 31 in the closure is fed by a line 32 containing air whose pressure can be varied to operate the dispenser as will be described hereafter.

Outlet 19 is in the end of a delivery pipe 33 which extends through the duct 28 and out through the end plate 30 to a second location 34 from which a line couples the pipe 33 to a mixing head of a polymer mixing machine.

The container 12 is provided with lid 13 to isolate the solvent contained in the container from the immediate locality of the device 11. The lid 13 serves also to laterally locate duct 28 and so contribute to a stable location of vessel 15 within the container 12.

In use with solvent added to the container to operating level, or higher, the component parts are set up as shown in the drawing and solvent added to provide an operating level 14 for solvent well above the vessel 15. Solvent enters and eventually fills the working volume 16 by way of inlet 17 and tube 20.

When solvent is to be dispensed an air over-pressure is applied by way of line 32 to duct 28 and so to working volume 16. Solvent in the working volume is pressurised and momentarily flows past the valve 25 until the overpressure cause the valve 25 to seat on the valve seat 24 so shutting off the inlet 17. The pressurised solvent in working volume 16 thereafter is caused to be driven though outlet 19 and along delivery pipe 33 to the second location 34 from which it passes to a dispensing mixing channel to provide for the cleaning of polymer residue arising from a mould filling operation. If the air over-pressure is maintained at the first location 31 by way of line 32 the working volume 16 is effectively emptied and delivery pipe 33 is blown forward and the pipe 33 dried out. The over pressure is then released and the device 11 then automatically operates to cause vessel 15 to be re-filled with solvent for as long as the solvent level within the container is sufficient.

A dispensing device according to the present invention provides a cheap and efficient means for applying a solvent flushing operation to a dispense machine mixing head involving the use of polymers.

Claims

1A dispensing device comprising: a container for solvent defining an operating level for solvent retained in the container; a vessel located within the container below the operating level, the chamber providing a working volume having an inlet, a port and an outlet; the inlet lying in a flow path between the container and the working volume including a valve adapted to resist a flow of liquid out of the working volume by means of the inlet while allowing a flow of liquid into the working volume by way of the inlet; the port linking the working volume by means of a duct to a first location outside the vessel and above the operating level; the duct being pressurisable by way of the first location to increase pressure in the working volume; and the outlet linking the working volume by means of a delivery pipe to a second location outside the vessel and above the operating level.

2 A dispensing device as claimed in Claim 1 wherein the delivery pipe extends through the port.

3 A dispensing device as claimed in any preceding claim wherein the container is provided with an aperture whereby solvent can be added to the container and the aperture is closed by means of a demountable closure.

4 A dispensing device as claimed in Claim 3 wherein the closure serves to support duct and/or the delivery pipe.

5 A dispensing device as hereinbefore described with reference to the accompanying drawing.