GB2220033A

GB2220033A - Fluidic pumping systems

Info

Publication number: GB2220033A
Application number: GB8815227A
Authority: GB
Inventors: John Russell Tippetts
Original assignee: UK Atomic Energy Authority
Current assignee: UK Atomic Energy Authority
Priority date: 1988-06-27
Filing date: 1988-06-27
Publication date: 1989-12-28
Anticipated expiration: 2008-06-27
Also published as: GB8815227D0; GB2220033B

Abstract

A fluidic pumping system has two reverse flow diverters 17, 18 respectively associated with a displacement vessel 13, 14 and arranged to deliver to a discharge line 19 via lines 20, 21 meeting at junction 24 which may include a fitter 31. The diverters 17, 18 have transverse passages respectively connected to opposed passages of a third reverse flow diverter 29 which can draw liquid at 30 from a chamber 11. Relatively high delivery pressure is obtained. <IMAGE>

Description

Fluidic Pumping Systems This invention relates to fluidic pumping systems.

British Patent specification 1480484 describes a pumping system including two reverse flow divertors (RFD). An RFD has a plenum chamber from which extend two opposed flow passages each of which diverges as it extends away from the chamber, at least one further passage extending laterally from the chamber to form an inlet passage for liquid. In the system described in 148084 each RFD has one of said opposed passages connected to a respective cylinder, the other of said opposed passages leading to an outlet or delivery passage; each RFD has two of said further passages which are opposed and communicate with a container for liquid; the cylinders are alternately pressurised with air to provide a substantially continuous delivery of liquid in the outlet or delivery passage.

According to the invention a fluidic pumping system comprises three reverse flow diverters, two of which diverters have a flow passage connected to a junction communicating with an outlet passage, two opposed flow passages of the third diverter respectively being connected to a liquid inlet passage of said two diverters.

The junction may include a filter.

The invention may be performed in various ways and one specific embodiment with possible modifications will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a pump arrangement; Figure 2 shows one form of RFD; and Figure 3 shows another form of RFD.

Figure 1 shows a pump arrangement 10 in the form of a double-acting fluidic pump in a container 11 for liquid 12. The pump arrangement 10 has containers or displacement vessels 13, 14 connected through lines 15, 16 respectively to RFD 17, RFD 18. RFD 17 has opposed diverging passages connected respectively to lines 15, 20 and RFD 18 has opposed diverging passages connected respectively to lines 21, 16 the lines 20, 21 leading to delivery passage 19, the containers 13, 14 being alternately pressurised through air or gas lines 22, 23.

Lines 20, 21 and passage 19 meet at junction 24. Each of the RFD 17, 18 has two further, transverse, passages 25, 26 Figure 2 one of which is closed and the other of which connects to line 27 or 28 respectively leading to opposed diverging passages of a further RFD 29 having a further, transverse, passage open to liquid 12. The overall effect is to induce liquid flow to the RFD 29 as indicated at 30. In this case also the junction 6 includes a filter 31 through which the liquid passes to discharge 19.

The circuit produces relatively high pressure (eg 5 bar) in the region of junction 24 when the maximum air pressure in 22 or 23 is at ambient pressure (1 bar absolute) for liquid 12 at 20iC for example.

Each of the RFD can be as in Figure 2, or preferably as in Figure 3 where the opposed passages 25a, 26a are initially of uniform section as they extend away from plenum chamber 32 and then widen or diverge; the length of the uniform section is greater than the width of the chamber between the passages 25a, 26a.

The opposed passages in RFD 29 are symmetrical but they need not be symmetrical in RFD's 17, 18. For example in RFD's 17, 18 the outer parts of the diverging opposed passages may have a greater angle of divergence then the inner parts of the passages, giving greater pressure at the filter.

The liquid flow in a first part of a cycle is from container 14, through pipe 16, RFD 18, pipe 21, filter 31 and pipe 19; and through pipe 30, RFD 29, pipe 27, RFD 17, pipe 15 into container 13. In a second part of the cycle flow is from container 13, through pipe 15, RFD 17, pipe 20, filter 31 to pipe 19t and through pipe 30, RFD 29, pipe 28, RFD 18, pipe 16 into cylinder 14.

During the first part of the cycle, flow also passes from the plenum of RFD 18 along pipe 28 to RFD 29 the effect of RFD 29 is to force the flow from it into RFD 17 thereby making it easy for the flow to be entrained by the flow from 30.

The same happens in reverse during the other half of the cycles.

A backflow retarder, such as a vortex diode or a diffuser, can be included in the inlet 30 to RFD 29 to reduce to a minimum any backflow.

Claims

1. A fluidic pumping system comprising three reverse flow diverters, two of which diverters have a flow passage connected to a junction communicating with an outlet passage, two opposed flow passages of the third diverter respectively being connected to a liquid inlet passage of said two diverters.

2. A system as claimed in Claim 1, in which the junction includes a filter.

3. A fluidic pumping system substantially as hereinbefore described with reference to and as shown in Figure 1 of the accompanying drawings.