WO1998046882A1

WO1998046882A1 - Apparatus for transferring viscous liquid

Info

Publication number: WO1998046882A1
Application number: PCT/GB1998/000949
Authority: WO
Inventors: Peter Howard Newton
Original assignee: Ilford Imaging Uk Limited
Priority date: 1997-04-12
Filing date: 1998-03-30
Publication date: 1998-10-22
Also published as: GB9707439D0

Abstract

An apparatus for moving a viscous liquid which comprises at least one closed vessel (1, 2) of oval or spherical shape which has fixed therein a flexible membrane (3, 4) which divides the vessel into two halves so that the liquid present in one half of the vessel cannot mix with the liquid in the other half of the vessel, valves (V2, V8) for supplying viscous liquid to one half of the vessel and valves (V4, V6) for enabling the viscous liquid to be withdrawn from this half of the vessel and a positive displacement pump (19) and inlet valves (V3, V5) for supplying propulsion liquid under pressure to the other half of the vessel and outlet valves (V1, V7) for enabling the propulsion liquid to be withdrawn from the vessel.

Description

Apparatus for transferring viscous liquid.

A large number of viscous liquids for example latexes coagulate when

subjected to a shearing force in a pump. This tends to cause the transferring

system to block up. Coagulated latex is very hard to remove from such a

blocked up system.

Various systems have been tried to overcome the problem for example the use

of pressurised vessels, double diaphragm pumps, mechanised gear pumps,

progressive cavity pumps and peristaltic pumps, but none of these have proved successful.

We have devised a new system which does not cause viscous liquids to

coagulate and which can be used to supply viscous liquids into a receiving

vessel or container, at a constant predetermined flow rate for a long period.

According to the present invention there is provided a prime mover for a

viscous liquid which comprises a closed vessel which has fixed therein a

flexible membrane which divides the vessel into two halves so that liquid

present in one half of the vessel cannot mix with liquid in the other half of the

vessel and means for supplying viscous liquid to one half of the vessel and

means for enabling the viscous liquid to be withdrawn from this half of the vessel and means for supplying propulsion liquid under pressure to the other

half of the vessel and means for enabling the propulsion liquid to be

withdrawn from the vessel.

In operation the viscous liquid is fed into the vessel so deforming the flexible

membrane so that it fills almost the whole of the vessel. Propulsion liquid is

then fed into the vessel so that in its turn it fills almost the whole of the vessel at the same time expelling the viscous liquid from the vessel.

Preferably the vessel is a sphere, spheroid or most preferably ovoid in shape.

Preferably vents are present in the vessel to enable it to be purged.

Preferably means are provided to enable the viscous liquid is fed by gravity to

the vessel. Preferably the propulsion liquid is water. Preferably the

propulsion liquid is forced under pressure into the vessel by means of a positive displacement pump.

Preferably the means for supplying viscous liquid into the vessel and for

enabling viscous liquid to be withdrawn from the vessel is a single pipe which

communicates with that part of the vessel in which the viscous liquid is to be

held, this single pipe leading to a T piece which has a valve in each branch. Preferably a similar single pipe connects with that part of the vessel in which

the propulsion liquid is held is a single pipe which leads to a T piece which

has a valve in each branch.

Preferably to ensure that the viscous liquid can be fed continuously from a

storage vessel to, for example, a mixing vessel two prime movers as

hereinbefore setforth are provided. However only one propulsion/liquid

storage vessel is required and only one positive displacement pump.

According to a preferred aspect of the present invention there is provided a

system for enabling viscous liquid to be transferred from a storage vessel to a

receiving vessel at a constant flow rate which comprises two prime movers for

a viscous liquid each of which comprises a closed vessel which has fixed

therein a flexible membrane which divides the vessel into two halves so that

liquid present in one half of the vessel cannot mix with liquid in the other half

of the vessel, means for supplying viscous liquid to one half of each vessel

and means for enabling the viscous liquid to be withdrawn from this half of

each vessel and means for supplying propulsion liquid under pressure to the

other half of each vessel and means for enabling the propulsion liquid to be

withdrawn from each vessel, a positive displacement pump which can be preset via a flow meter to pump propulsion fluid from a storage vessel at a

constant flow rate into the vessels.

Preferably in this system both vessels are ovoid. Preferably in this system the

propulsion liquid is water.

The operation of a tandem of two prime movers as set forth above to provide a

continuous flow of viscous fluid to a mixing vessel will now be described

with reference to the accompanying figure.

In the figure, there is shown two closed vessels 1 and 2 and each is divided in

half by flexible membranes 3 and 4. Valves V2-V8 are shown in position.

Valves V2 and V4 are in the T piece connected to inlet/outlet pipe 6 and

Valves V6 and V8 are in the T piece connected to inlet/outlet pipe 7. Valves

VI and V3 are in the T piece connected to inlet/outlet pipe 8 and Valves V5

and V7 are in the T piece connected to inlet/outlet pipe 9. Pipe ends 10 and

12 are connected to a supply of viscous liquid (not shown). Pipe end 13 is

connected to a mixing vessel (not shown).

Each of the valves VI, V3, V5 and V7 are connected to pipe 14 which leads

into a liquid propulsion storage container 16. Attached to the bottom of liquid

storage container 16 via a pipe 18 is a positive displacement pump 19. To commence operations both vessels 1 and 2 are empty of all liquids but full of

air and pump 19 is set to pump propulsion liquid into vessels 1 and 2 at that

rate at which it is required for the viscous liquid to be pumped into the mixing

vessel.

The valves V2 & VI are opened and the viscous liquid flows by gravity from

a viscous liquid storage vessel via pipes 10 and 6 to fill completely vessel 1 ,

the membrane being deformed by the weight of the viscous liquid to ensure

vessel 1 is full of viscous liquid. Valve 8 & V7 are also opened to allow

viscous liquid to flow via pipes 12 and 7 in to and to fill vessel 2. When full

VI, V2 and V7, V8 are closed respectively. When Vessel 2 is full and V7 and

V8 closed then V6 opens. Valve 4 is then opened and also valve 3. The pump

19 is then started and propulsion liquid is then pumped from storage vessel 16

into the lower half of vessel 1. This forces the viscous liquid out of vessel 1

into a mixing vessel via pipes 6 and 13, the viscous liquid flowing at the

required flow rate. Then when a sensor (not shown) indicates that vessel 1 is

almost empty of viscous liquid valve V5 is opened and the propulsion liquid is

then split randomly between the two vessels 1 and 2 and some liquid then

leaves vessel 2 via pipes 9, 7 and 13. Then valve V3 closes. When V3 is fully-

closed 1 valves VI and V4 are closed and valve V2 and VI are opened

Vessel 1 then fills with viscous liquid whilst vessel 2 is being emptied. The

operation is then repeated until the required amount of viscous liquid has been received in the mixing vessel or if it is a continuous process of several hours

for the requisite time.

The system has been tested over 24 hours continuous running providing a

non-pulsating flow at the required flow rate over this period. No blockage of

the pipes or prime mover occurred. The viscous liquid used was a latex.

Using the other prime movers the systems latex coagulates and blocks up after

a few hours.

When two such vessels are used in tandem a constant flow of viscous liquid

can be delivered to the mixing chamber because one chamber delivers the

viscous liquid whilst the other vessel is recharging. When one vessel is

almost empty there is an overlap at which point the propulsion liquid supply is

split between both vessels. Because the propulsion liquid is fed into the

system at the required flow rate this ensures that the correct flow rate out of

the system into the mixing or receiving vessel is maintained.

Claims

Claims :-

1. A prime mover for a viscous liquid which comprises a closed vessel

which has fixed therein a flexible membrane which divides the vessel

into two halves so that liquid present in one half of the vessel cannot

mix with liquid in the other half of the vessel, means for supplying

viscous liquid to one half of the vessel and means for enabling the

viscous liquid to be withdrawn from this half of the vessel and means

for supplying propulsion liquid under pressure to the other half of the

vessel and means for enabling the propulsion liquid to be withdrawn from the vessel.

2. A prime mover according to Claim 1 wherein the closed vessel is a

sphere, spheroid or ovoid.

3. A prime mover according to Claim 1 which comprises means to enable

the vessel to be fed the viscous liquid by gravity.

4. A prime mover according to Claim 1 wherein the propulsion liquid is water.

5. A prime mover according to Claim 1 which comprises a positive displacement pump to force the propulsion liquid into the vessel.

6. A prime mover according to Claim 1 wherein the means for supplying

viscous liquid into the vessel and for enabling viscous liquid to be

withdrawn from the vessel is a single pipe which communicates with that part of the vessel in which the viscous liquid is to be held, this

single pipe leading to a T piece which has a valve in each branch.

7. A prime mover according to Claim 1 wherein the means for supplying propulsion liquid into the vessel and for enabling propulsion liquid to be withdrawn from the vessel is a single pipe which communicates

with the part of the vessel in which the propulsion liquid is held, this

single pipe leading to a T piece which has a valve in each branch.

8. A system for enabling viscous liquid to be transferred from a storage

vessel to a receiving vessel at a constant flow rate which comprises

two prime movers for a viscous liquid each of which comprises a

closed vessel which has fixed therein a flexible membrane which divides the vessel into two halves so that liquid present in one half of

the vessel cannot mix with liquid in the other half of the vessel, means

for supplying viscous liquid to one half of each vessel and means for enabling the viscous liquid to be withdrawn from this half of each vessel and means for supplying propulsion liquid under pressure to the other half of each vessel and means for enabling the propulsion liquid

to be withdrawn from each vessel, a positive displacement pump

which can be preset to pump propulsion fluid from a storage vessel at a constant flow rate into the vessels.

9. A system according to Claim 8 wherein both vessels are ovoid.

10. A system according to Claim 8 wherein the propulsion liquid is water.