GB2235497A

GB2235497A - Fluidic pumping systems

Info

Publication number: GB2235497A
Application number: GB8919838A
Authority: GB
Inventors: Douglas Edward Parker
Original assignee: UK Atomic Energy Authority
Current assignee: UK Atomic Energy Authority
Priority date: 1989-09-01
Filing date: 1989-09-01
Publication date: 1991-03-06
Also published as: GB8919838D0

Abstract

In a fluidic pumping system, including a charge vessel 4 and RFD (reverse flow diverter, 1), liquid is drawn into the charge vessel until the liquid reaches an upper level as determined by a pair of probes 5, 6 the ends of which are spaced vertically apart. When gas, conveniently air, is blown down the probes the differential pressure between the two probes is related to the density of fluid about the ends of the probes and is utilised to indicate the liquid level. <IMAGE>

Description

Improvements in fluidic pumping systems The present invention concerns pumping systems incorporating fluidic devices.

A known pumping system incorporates a fluidic device known as a reverse flow diverter, RFD, and reference can be made to British Patent Specification No 1,480,484 for examples of RFD's and their manner of operation. The pumping systems require means for controlling operations and an example of such control means is given in British Patent Specification No 2,157,368B.

The present invention concerns an alternative manner of controlling operation of a fluidic pumping system.

According to the present invention a method of controlling the operation of a fluidic pumping system comprises detecting a pressure change resulting from a change in level of liquid in a charge vessel of the system.

The invention will be described, by way of example, with reference to the accompanying diagrammatic illustration of a control means for a fluidic pumping system.

A fluidic pump element 1 comprises a RFD in communication with a supply of liquid to be pumped along line 2. The opposite end of the RFD is connected by line 3 to a charge vessel 4 and for a more detailed description of the arrangement reference is made to Patent Specification No 2157368B.

During a suction stroke the charge vessel 4 is refilled with liquid and the suction stroke is terminated when the liquid level reaches the top of the charge vessel The liquid level is determined by a pair of probes 5 and 6, known as pneumercators, the ends of which are inserted into the top of the charge vessel.

As shown the ends of the pneumercators are spaced apart by a short vertical distance. Air (or other gas) is blown down the pneumercators 5 and 6 and the differential pressure between the two pneumercators is determined by a pressure transducer 7. The pressure reading is directly proportional to the density of the fluid between the ends of the two pneumercators 5 and 6 in the charge vessel 4. It is therefore possible to distinguish between air or gas about the ends of the pneumercators 5 and 6 and a liquid. This with the ends of the pneumercators immersed in liquid the resulting signal at the transducer 7 will indicate the charge vessel is full. The signal is utilised to initiate the next stage in the pumping cycle by controlling the operation of jet pumps 8 and 9.

Claims

1. A method of controlling the operation of a fluidic pumping system which comprises extending a pair of tubular probes into a charge vessel of the system, spacing the ends of the probes apart by a short vertical distance, blowing gas through the probes into the charge vessel, monitoring the pressure differential between the two probes and utilising the resulting signal, which is indicative of the fluid about the ends of the probes, to control operation of the system.

2. A method of controlling the operation of a fluidic pumping system substantially as herein described with reference to the accompanying drawing.