GB2429786A

GB2429786A - Pressure testing apparatus

Info

Publication number: GB2429786A
Application number: GB0517900A
Authority: GB
Inventors: Ian Geoffrey Sutton
Original assignee: ANTHIRE Ltd
Current assignee: ANTHIRE Ltd
Priority date: 2005-09-02
Filing date: 2005-09-02
Publication date: 2007-03-07
Anticipated expiration: 2025-09-02
Also published as: GB0517900D0; GB2429786B

Abstract

There is disclosed a pressure testing apparatus which comprises an inlet 1 for a pressure testing fluid at a first pressure. The inlet 1 is connected to a pressure reducing valve 2 for reducing the pressure of the pressure testing fluid to a second pressure. The pressure reducing valve 2 is connected to a recirculation tank having an upper part and a lower part, the lower part of the recirculation tank being connected to an inlet of a pump 7 adapted to pump the pressure testing fluid at a pressure higher than the first and second pressures. An outlet 8 of the pump is connected to a two-way junction 9 having first 14 and second 10 branches, the first branch being connected to an inlet of a flow meter 15 and an outlet of the flow meter being adapted for connection to a system to be tested. The second branch is connected to an inlet of a back pressure regulating valve 11 for regulating the pressure of the pressure testing fluid in the first and second branches and the system to be tested so as to maintain a substantially constant third pressure that is higher than the first and second pressures. An outlet 12 of the back pressure regulating valve is connected to the recirculation tank, and the upper part of the recirculation tank is provided with an air valve 19 for de-gassing the pressure testing fluid. The apparatus avoids the problems caused by excessive frictional heating of pressure testing fluids, and is more stable in operation than existing pressure testing systems.

Description

PRESSURE TESTING APPARATUS

BACKGROUND

The present invention relates to pressure testing apparatus for testing the integrity of mains water pipes, shipping vessels and other fluid storage or transport means, and in particular but not exclusively to a portable unit for pressure testing of pipelines and the like.

When installing mains water pipes, it is important to test the integrity of the installation prior to commissioning. It is also desirable to be able to test the integrity of the installation at other times, for example to detect leaks. This applies also to vessels for storing or transporting fluids generally, such as tankers and the like. * **

Typical existing apparatus uses a high pressure pump directly to supply water at a * predetermined pressure to a sealed water pipe system. The pressure of the water within * * s the pipe is monitored, and the presence of leaks is indicated by falling pressure. Direct s's.

application of high pressure fluids can, however, put undue strain on the pump, and it ass...

* can be difficult to maintain a desired high pressure within closely defined tolerance * 20 boundaries. I 555 5. I S 5

* BRIEF SUMMARY OF THE DISCLOSURE

According to the present invention, there is provided a pressure testing apparatus comprising an inlet for a pressure testing fluid at a first pressure, the inlet being adapted for connection to a pressure reducing means for reducing the pressure of the pressure testing fluid to a second pressure, the pressure reducing means being adapted for connection to a recirculation tank having an upper part and a lower part, the lower part of the recirculation tank being adapted for connection to an inlet of a pump adapted to pump the pressure testing fluid at a pressure higher than the first and second pressures, an outlet of the pump being adapted for connection to a two-way junction having first and second branches, the first branch being adapted for connection to an inlet of a flow meter and an outlet of the flow meter being adapted for connection to a system to be tested, the second branch being adapted for connection to an inlet of a back pressure regulating means for regulating the pressure of the pressure testing fluid in the first and second branches and the system to be tested so as to maintain a substantially constant third pressure that is higher than the first and second pressures, an outlet of the back pressure regulating means being adapted for connection to the recirculation tank, and the upper part of the recirculation tank being provided with means for de-gassing the pressure testing fluid.

The present invention thus provides an inlet for pressure testing fluid at the first pressure, and a recirculation circuit (comprising the recirculation tank and pipe work to the pump and pipe work from the outlet of the back pressure regulating means back to the recirculation tank) in which the pressure testing fluid recirculates at the second pressure. The present invention also provides an outlet from the pump to the first branch of the two-way junction to the flow meter for connection to a pipe to be tested, and to the second branch of the two-way junction to the inlet of the back pressure regulating means, in which the pressure testing fluid is maintained substantially at the third pressure.

* Provision of the recirculation circuit operating at the second, relatively low pressure * * ** results in good flow stability and helps to avoid undue forcing of the pump. Moreover, I...

* * the de-gassing means allows air and other gases to be removed from the pressure testing fluid in the recirculation circuit.

: * : The inlet to the pressure reducing means may be connected to a supply of, for example, mains pressure water, which typically has a pressure (the first pressure) of 200 to 800kPa (2 to 8 bar). The pressure reducing means may be a pressure reducing valve of known design.

In a particularly preferred embodiment, the pressure reducing means lowers the pressure of the pressure testing fluid to around or substantially l5OkPa (1.5 bar), this being the second (recirculation) pressure.

The recirculation tank may take any desired form, and in a preferred embodiment comprises a generally upright cylinder having upper and lower ends. In one particular embodiment, the cylinder may have a volume of substantially 500m1. The lower end of the recirculation tank may be provided with a pressure relief valve adapted to allow release of the pressure testing fluid should the second pressure increase above a predetermined maximum value (for example 200kPa if the intended operational pressure is l5OkPa).

The lower end of the recirculation tank is connected, via an optional strainer, to a pump which is adapted to pump the pressure testing fluid at a pressure which will generally be higher than the first, second and third pressures. The back pressure regulating means is adjusted so as to set the third pressure in the first and second branches of the two- way junction and also in the system to be tested.

The back pressure regulating means may comprise a back pressure regulating valve or any other type of back pressure regulator, for example an adjustable back pressure regulating piston valve with a spring- loaded adjustable piston adapted to maintain the third pressure by relieving excess pressure from the pump through the outlet of the back pressure regulating valve back into the recirculation circuit (generally its upper part).

: ** The third pressure is significantly higher than the first and second pressures, and is * 15 selected to be an appropriate testing pressure for the system to be tested. For example, * 1 where the first pressure is 200 to 800kPa and the second pressure is around I 5OkPa, then the third pressure may be 900 to l800kPa. It will, however, be appreciated that : other pressure ranges may be useful. In general, the first pressure is greater than the second pressure, and the third pressure is greater than both the first and second pressures. S. S * * * **

Advantageously, the pump is driven by an internal combustion motor rather than an electric motor, since this simplifies installation and makes compliance with safety regulations easier to achieve.

The first branch of the two-way junction is connected to the inlet of the flow meter, and the outlet of the flow meter then provides a connection to the system to be tested. The flow meter can measure the volume of pressure testing fluid required to pressurise the system to be tested, and measures the volume of any leakage from the system to be tested when the pressure testing fluid is passing through the flow meter to maintain the third pressure in the system.

A pressure gauge may be provided and connected to any part of the apparatus at the third pressure. Usually, the pressure gauge is connected to the outlet of the flow meter.

The pressure gauge is used to monitor the third pressure.

In use, the apparatus is operated so as to fill and pressurise the system to be tested, and the back pressure regulating means is then adjusted while monitoring the pressure gauge so as to set and maintain the third pressure in the system to be tested.

The de-gassing means, which may take the form of an air valve, preferably an automatic air valve, is mounted on top of the upper part of the recirculation tank. The air valve helps to remove any gas bubbles that may have been generated in the recirculation circuit and thereby helps to ensure full running and also helps to maintain the second pressure at its desired level. Moreover, the de-gassing means removes air or other gas from the system that might otherwise lead to the formation of air/gas pockets.

One particular advantage of the recirculation circuit is that it provides a means for recirculating together variable excess pressure testing fluid volume from the parts of the : ** apparatus at the third pressure back to the pump inlet at the relatively stable second pressure. Any pressure testing fluid drawn off through the flow meter from the parts of the apparatus at the third pressure is replaced by pressure testing fluid reduced down to * * the second pressure from the supply at the first pressure. This helps to avoid significant ** S. * : *.: heating the pressure testing fluid as a result of the friction that would be encountered when passing the fluid through a narrow valve, which is the normal way of providing a * 20 small volume of pressure testing fluid at high pressure. S. S * * . * ..

Advantageously, embodiments of the present invention may be provided with telemetry means which allow the apparatus to be operated from a remote location.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show how it may be carried into effect, reference shall now be made by way of example to the accompanying drawing, in which: FIGURE 1 shows an embodiment of the invention in schematic form.

DETAILED DESCRIPTION

: Figure 1 shows a pressure/flow diagram illustrating a preferred embodiment of the present invention. * * S...

* * An inlet 1 is provided for connection to a mains water supply, typically at around 200 to I...

800kPa (the first pressure). A pressure reducing valve 2 reduces the water pressure to a recirculation pressure (the second pressure) of around 1 5OkPa and supplies water at * . : * 20 the second pressure to a 500mI upright cylindrical recirculation tank 3. A 200kPa relief valve 4 is provided at the bottom of the recirculation tank 3, as is an outlet 5 to a strainer 6. An outlet 7 from the strainer 6 passes to a 13 litres/minute piston pump 7, which is preferably driven by an internal combustion engine (not shown). The pump 7 has an outlet 8 that connects to a two-way junction 9.

One branch 10 of the two-way junction 9 leads to a piston type back pressure regulator valve 11. This valve 11 includes an adjustable, springloaded piston (not shown) and is adjustable so as to maintain a predetermined testing pressure (the third pressure) of 900 to l800kPa in the branch 10. This is achieved by relieving excess pressure through an outlet 12 and along a pipe 13 back to the top of the recirculation tank 3. Water flowing back to the recirculation tank 3 by way of pipe 13 will generally be at or close to the second pressure.

The other branch 14 of the two-way junction 9 passes to an inlet of a flow meter 15 including a pulse generator 16 allowing flow to be measured. An outlet 17 from the flow meter 15 is provided with a pressure gauge 18 and connects to the system to be tested (not shown). The pressure in the first and second branches 10, 14 and also in the outlet 17 and the system to be tested is maintained at the third pressure. Any leakage from the system to be tested is replenished (and thus the third pressure is maintained) by water from the recirculation circuit defined by the recirculation tank, strainer, pump and back pressure regulator, and the volume of leakage is determined by the flow meter 15.

The pump 7 will generally operate at a pressure higher than the third pressure, but excess pressure is relieved by way of the back pressure regulator 11.

An automatic air valve 19 is provided at the top of the recirculation tank 3 so as to remove any air from the recirculation circuit that might otherwise cause instability in the apparatus. * ** * S * S.. * * S** * * *.*. * S.I * S

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Claims

1. A pressure testing apparatus comprising an inlet for a pressure testing fluid at a first pressure, the inlet being adapted for connection to a pressure reducing means for reducing the pressure of the pressure testing fluid to a second pressure, the pressure reducing means being adapted for connection to a recirculation tank having an upper part and a lower part, the lower part of the recirculation tank being adapted for connection to an inlet of a pump adapted to pump the pressure testing fluid at a pressure higher than the first and second pressures, an outlet of the pump being adapted for connection to a two-way junction having first and second branches, the first branch being adapted for connection to an inlet of a flow meter and an outlet of the flow meter being adapted for connection to a system to be tested, the second branch being adapted for connection to an inlet of a back pressure regulating means for regulating the pressure of the pressure testing fluid in the first and second branches and the system to be tested so as to maintain a substantially constant third pressure that is higher than the first and second pressures, an outlet of the back pressure regulating means being adapted for connection to the recirculation tank, and the upper part of the recirculation tank being provided with means for de-gassing the pressure testing fluid.

* 20

2. An apparatus as claimed in claim 1, wherein the recirculation tank is provided * with pressure relief means.

3. An apparatus as claimed in any preceding claim, wherein a strainer is provided between the recirculation tank and the pump.

4. An apparatus as claimed in any preceding claim, wherein the back pressure regulating means is a spring-loaded piston type back pressure regulator.

5. An apparatus as claimed in any preceding claim, wherein a pressure gauge is provided for measuring the third pressure.

6. An apparatus as claimed in any preceding claim, wherein the pump is driven by an internal combustion motor.

7. An apparatus as claimed in any preceding claim, further provided with telemetry means for allowing the apparatus to be operated from a remote location or for pressure and/or flow rate measurements taken by the apparatus to be transmitted to a remote location.

8. An apparatus as claimed in any preceding claim, wherein the apparatus is provided with means for applying the third pressure to the system to be measured for a predetermined time, and wherein the flow meter measures a volume of any loss of pressure testing fluid from the system to be tested.

9. An apparatus as claimed in any preceding claim, wherein the recirculation tank is cylindrical.

10. An apparatus substantially as hereinbefore described with reference to or as shown in the accompanying drawing. * I. * U * I.. * Uèf * U I,,.

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