IES84956Y1 - A refrigeration system testing tool and method - Google Patents

Abstract

ABSTRACT A refrigeration system testing tool comprises a manifold (2) of stainless steel tubing and charging and testing hoses (3 and 4) connected to the manifold by pressure connection fittings. Also, there are in-line, shut off valves (5, 6) for the hoses (3 and 4) respectively, and a stainless steel graduated pressure gauge (10). There is also a stainless steel shut—off, pressure relief, and charging valve (1 1) with variable flow positioning allowing infinite regulation of Nitrogen charge, and also system relieving once a test has been completed. A safety pressure relief valve (12) is screwed directly into the manifold (2), for monitoring the system test pressure fi'om a safety perspective and automatically relieving to atmosphere in the event of excessive pressure being detected. A mounting bracket (20) is secured by a bracket (21) to the manifold (2). The tool (1) can be very conveniently used to complete installation.

Description

A Refrigeration System Testing Tool and Method Introduction The invention relates to testing and installation of refhgeration systems.

Refiigeration systems must be placed under vacuum and pressure tested prior to start- up and operation. This procedure is generally completed by a commissioning engineer and is very much reliant on the level of expertise. The European Pressure Equipment Directive (PED) No. 97/23/EC came into force to monitor and regularise the procedures followed during a system pressure test.

In order to comply with this Directive, when a refrigeration system is being tested, dependant on size and complexity, it must reach a factor of minimum 1.1 times the maximum operating pressure of the system.

A conventional manifold system consists of two gauges indicating the low and high side system pressures during operation and charging. The accuracy and construction of the valve arrangement means that the use of secondary relief valves and gauges is needed during the pressure testing of a system so that the complete installed system package is compliant with the regulations. In addition, the risk of overcharging the system, coupled with the associated damage to equipment and especially personnel was unsatisfactory.

US6038929 describes a system having an hydraulic cylinder for testing the pressure in a fluid system.

US4984448 describes a pressure/leak detector which connects to a port of a low pressure fluid system.

JPIIOO6782 describes a system for pressure testing a refrigeration system. This system is complex, having an electronic control system and requiring electrical power.

The invention is directed towards providing an improved tool and method for refrigeration system testing.

Summary of the Invention According to the invention, there is provided a refrigeration system testing tool comprising a manifold, a plurality of conduits extending from the manifold, said conduits having a strength to withstand both low and high refrigeration system pressures and being configured for connection to refrigeration system high and low pressure circuits, a charging valve means on the manifold, a pressure relief valve means on the manifold, and a pressure gauge on the manifold.

In one embodiment, the conduits are hoses.

In another embodiment, the conduits extend from opposed ends of the manifold.

In a further embodiment, the manifold is tubular.

In one embodiment, the manifold comprises a main portion having a first diameter and is tapered at its ends down to a reduced diameter.

In another embodiment, the charging valve means and the relief valve means are mounted on the manifold main portion.

In a further embodiment, the charging valve means and the relief valve means are an integrated charging/relief valve.

In one embodiment, the pressure gauge is mounted on the manifold main portion.

In another embodiment, the tool further comprises a shut-off valve for each conduit.

In a further embodiment, each shut-off is connected between the manifold and the conduit.

In one embodiment, the tool further comprises a safety pressure relief valve on the manifold.

In another embodiment, further comprising a support bracket secured to the manifold and being arranged to be secured to a support means.

In another aspect, there is provided a method of commissioning a refrigeration system using a tool as claimed in any preceding claim, the method comprising the steps of: connecting the conduits to the refrigeration system low and high pressure circuits, connecting a vacuum pump to the pressure relief valve means, and evacuating the refrigeration system via the pressure relief valve means, the manifold, and the conduits; monitoring pressure indicated on the gauge to determine that the system is adequately evacuated; connecting a pressurized fluid supply to the charging valve means or to a conduit, and pressurising the system via the manifold and one or both conduits; monitoring pressure in the manifold according to the pressure gauge, and if pressure fluctuations occur over time, indicating that the refrigeration system potentially has a leak and discontinuing the method; if no such fluctuations occur, discharging the charging fluid from the refrigeration system via the relief valve means; connecting a refrigerant supply to the charging valve means or a conduit, and delivering refrigerant to the refrigeration system via the manifold and one or both of the conduits, and monitoring pressure of refrigerant in the refrigeration system until a target pressure is reached; and isolating the tool from the refrigeration system and closing refiigeration system charging valves to retain the refrigerant n the refrigeration system circuits.

In one embodiment, the tool is initially secured to a support adjacent the refrigeration system.

In another embodiment, the method comprises the further step of closing the shut-off valves on the tool before closing the refrigeration system valves.

Description of the Invention The invention will be more clearly understood from the following description of some embodiments thereof given by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a testing tool of the invention.

Referring to Fig. 1 a testing tool 1 has the following components: Manifold of 65mm stainless steel tubing with three pilot ports.

Charging and testing hoses, 15mm internal diameter, 3m long, and being connected to the manifold by pressure connection fittings.

Brass, in-line, shut-offvalves for the hoses 3 and 4 respectively.

Stainless steel graduated pressure gauge capable of reading up to 50 bar with accuracy to +/-0.09bar. This gauge is fitted to the manifold 2 via a 19mm internal diameter stainless steel socket.

A stainless steel shut-off, pressure relief, and charging valve with variable flow positioning allowing infinite regulation of nitrogen charge, and also system relieving once the test has been completed. This valve is, in use, connected directly to a nitrogen charge or a system vacuum pump.

A safety pressure relief valve screwed directly into the manifold 2, for monitoring the system test pressure from a safety perspective and automatically relieving to atmosphere in the event of excessive pressure being detected. This valve is fitted with a 31 bar burst unit, however this is interchangeable and can be selected to suit the particular application , Mounting bracket, of inverted U-shaped channel construction, secured by a bracket 21 to the manifold 2.

The tool 1 can be very conveniently used to complete installation of a refrigeration system to charge it and to test it. The following is one example of its use.

Steps: (21) Once the refrigeration system has been constructed and all pipes and Valves welded into position, the tool 1 is fixed to a support structure near valves of the refrigeration system via the mounting bracket 20. (b) The tool 1 hoses 3 and 4 are connected to the refrigeration system via the suction and discharge service valves on the compressor (low side) and the receiver (high side) of the refrigeration system. Initial vacuuming of the refrigeration system is completed by connecting a vacuum pump to the valve 1 1, to evacuate the refrigeration system through the valve 11. The refrigeration system is now ready for pressure testing. (c) A nitrogen bottle is connected to the valve 11 on the tool 1 and is made ready. (d) The connections on the gauge 10 and the valve 11 are checked and tightened. (e) The nitrogen bottle is opened and the gas pressure regulated into the system via the manifold 2 until a measured 27 bar is indicated on the gauge 10. This pressure may be different, dependent on the system type. This pressure is applied via both of the hoses 3 and 4 to both sides (high and low pressure) of the refrigeration system. (t) The system is then left for a defined period and the system pressure is measured on the gauge 10 over a period of time.

Once it is clear that there are no leaks, the system charge is relieved and safely discharged to atmosphere via the primary relief ball valve on the charging relief port of the valve 1]. As the pressure test has been completed the system is now ready for charging with refiigerant.

As an alternative to steps (c) to (g), during pressure testing the valve 11 may be isolated, a hose 3 or 4 connected to the nitrogen bottle, and the other hose 3 or 4 charging the system. In this arrangement, the system is charged only via one port, not two. However, a convenient aspect is that the valve 11 may be used as a relief valve for increased speed of discharge of system pressure.

Refrigerant is charged through the charging valve 11, the manifold 2, and one of the hoses 3 or 4, and based on the calculated weight of system charge required this will accurately charge the system in a visible and protected manner. In alternative arrangements the charging may be through a hose and out the other hose. The latter arrangement may be desirable where the system is in a small or hazardous room, in which case it is desirable to have the bottle outside and the combined lengths of the two hoses 3 and 4 and the manifold 2 extend the safe working distance. However, it should be noted that where the valve ll is isolated and the hoses 3 and 4 are used for inlet and outlet, the manifold 2 is still at all times the master, with the gauge 10 indicating the relevant pressure whether for vacuuming, pressure testing, or refrigerant charging. The pressure within the manifold and the system pipe—work is indicated on the gauge 10 throughout the vacuuming, pressure testing and charging of the installation irrespective of the arrangement used.

When the system charge has been reached and verified, the connection hose shut-off valves 5 and 6 are closed, the service valves on the system are set to run, and the tool 1 is disconnected. Disconnection is on each side separately.

During the charging, pressure testing or vacuuming of the installed refrigeration system there are occasions when the vacuum pump, nitrogen bottle or refrigerant charging bottle needs to be isolated from the system while still displaying the actual calibrated reading on the manifold gauge. In this instance the in-line shut-off valves 5 and 6 on the flexible lines are closed off, isolating the external pressure source while still allowing the pressure to be monitored and the safety relief function to be in place.

The tool is flexible enough to adapt to a wide range of refrigeration applications big or small, because during a new installation it requires no local electrical supply, can regulate any amount of nitrogen or refrigerant into the installation irrespective of system size, provides a safe working enviromnent for personnel using the system, and complies with the current and known legislative requirements.

In addition, it speeds up the connection/testing process because a single manifold arrangement covers the total requirement for vacuuming, pressurisation, holding/verification, relief and system charging. Further, it provides all information/precautions necessary to meet the requirements for safe working environments.

Advantageously, the tool can be used for system pressure testing, vacuuming, charging and as a service tool during the lifetime of the refrigerant equipment as part of a certified maintenance check regime.

The invention is not limited to the embodiments described, but may be varied in construction and detail.

Claims (1)

Claims A refrigeration system testing tool comprising a manifold, a plurality of conduits extending from the manifold, said conduits having a strength to withstand both low and high refiigeration system pressures and being configured for connection to refiigeration system high and low pressure circuits, a charging valve means on the manifold, a pressure relief valve means on the manifold, and a pressure gauge on the manifold. A refrigeration system testing tool as claimed in claim 1, wherein the conduits are hoses; wherein the conduits extend from opposed ends of the manifold; wherein the manifold is tubular; wherein the manifold comprises a main portion having a first diameter and is tapered at its ends down to a reduced diameter; wherein the charging valve means and the relief valve means are mounted on the manifold main portion; and wherein the charging valve means and the relief valve means are an integrated charging/relief valve. A refrigeration system testing tool as claimed in claim 2, wherein the pressure gauge is mounted on the manifold main portion; and wherein the tool further comprises a shut-off valve for each conduit. A refrigeration system testing tool as claimed in claim 3, wherein each shut-off is connected between the manifold and the conduit; wherein the tool further comprises a safety pressure relief valve on the manifold; and wherein the tool further comprises a support bracket secured to the manifold and being arranged to be secured to a support means. A method of commissioning a refrigeration system using a tool as claimed in any preceding claim, the method comprising the steps of: connecting the conduits to the refrigeration system low and high pressure circuits, connecting a vacuum pump to the pressure relief valve means, and evacuating the refrigeration system via the pressure relief valve means, the manifold, and the conduits; monitoring pressure indicated on the gauge to detennine that the system is adequately evacuated; connecting a pressurized fluid supply to the charging valve means or to a conduit, and pressurising the system via the manifold and one or both conduits; monitoring pressure in the manifold according to the pressure gauge, and if pressure fluctuations occur over time, indicating that the refrigeration system potentially has a leak and discontinuing the method; if no such fluctuations occur, discharging the charging fluid from the refrigeration system via the relief valve means; connecting a refrigerant supply to the charging valve means or a conduit, and delivering refrigerant to the refrigeration system via the manifold and one or both of the conduits, and monitoring pressure of refrigerant in the refrigeration system until a target pressure is reached; and isolating the tool from the refrigeration system and closing refiigeration system charging valves to retain the refrigerant in the refrigeration system circuits. 884956

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