WITT Refrigerant Pumps in India: GP51, GP Series and HRP Selection Guide

Industrial refrigeration plants rarely fail because someone forgot the word “pump” in the design. Problems usually begin when the refrigerant pump is selected from refrigeration tonnage alone.

A pumped ammonia system has to move liquid refrigerant through real pipework, valves and evaporators while the plant load keeps changing. During pull down or compressor capacity changes, vapour can reach the pump suction. That is why a dedicated refrigerant pump matters.

For anyone searching for a WITT refrigerant pump in India, the correct starting point is the operating duty: refrigerant, evaporating temperature, required liquid flow, delivery head, recirculation rate and pressure class. Metalex presents the TH. WITT refrigerant pump portfolio for industrial refrigeration applications in India.

Where the WITT GP51 fits

The WITT GP51 is part of the GP Series of open type refrigerant pumps with a flanged standard motor. TH. WITT describes the GP range as suitable for refrigerants including ammonia and designed around robust construction, easy maintenance and strong spare parts availability.

Current WITT GP data lists the GP51 with DN50 suction and discharge connections, maximum flow around 16.8 m³/h at 50 Hz and 20 m³/h at 60 Hz, with maximum delivery head around 31 m at 50 Hz and 47 m at 60 Hz. These figures are model data, not a substitute for a project selection.

The point is important: two 300 TR plants can need different pumps because pipe losses, evaporator layout and recirculation rate are different.

GP Series or HRP Series?

The WITT GP Series is the open type direction. It uses a standard flanged motor, double shaft seal, barrier oil reservoir and sight glass. This can suit plants where service access and conventional motor replacement are valued. TH. WITT also notes that the GP range has a long record in ammonia refrigeration and can tolerate short periods of gas intake better than a conventional liquid pump.

The WITT HRP Series uses a hermetic canned motor. TH. WITT positions HRP pumps for duties where a maintenance free execution or higher operating pressure is required. The current family includes HRP3232, HRP5040, HRP5050, HRP8050 and HRP10080, with different flow, head and pressure classes.

A simple first review is:

Final selection still depends on the actual hydraulic duty.

Why ammonia recirculation pumps need careful suction design

A refrigerant pump does not receive calm liquid all day. The liquid can be close to boiling, and pressure loss in the suction line can create flash gas. TH. WITT guidance warns that vapour can increase during pull down and compressor capacity changes, reducing liquid mass flow if suction conditions are poor.

That is why suction piping, separator liquid level and pump elevation matter. A bigger motor does not correct a bad suction arrangement.

In a liquid overfeed system, the pump sends more liquid to the evaporator than can evaporate in one pass. Excess liquid returns to the separator and is circulated again. This architecture is relevant to cold storage, dairy refrigeration, seafood processing and food processing plants. For wider dairy-industry context, Milky Mist Dairy Food Limited is a useful example of the scale and product diversity now seen in India's value-added dairy sector. This reference is included as industry context only and does not imply a project or supply relationship.

Data Metalex needs before selecting a WITT pump

Before asking for a GP51, GP42 or HRP model, prepare:

• Refrigerant, such as R717 ammonia
• Evaporating temperature
• Required liquid flow in m³/h
• Required delivery head in metres
• Desired recirculation rate
• Separator level and pump elevation
• Existing suction and discharge pipe sizes
• Voltage and frequency
• Existing pump model and nameplate photo for replacement work

If flow is not known, send refrigeration capacity, operating condition and recirculation requirement so the hydraulic duty can be reviewed. “Need pump for 300 TR” is not enough.

More WITT products used in industrial refrigeration

The Metalex WITT section covers more than the GP51. It includes GP open type pumps, HRP hermetic pumps, high pressure float regulators, level protection, oil management equipment and pumping station concepts. Metalex’s current partner page describes WITT technology around refrigerant circulation, separation and oil management.

That wider portfolio matters because pump reliability is tied to the rest of the low pressure system. Liquid level, separator performance, oil return, valves and control logic all influence the pump.

Metalex can also connect the pump discussion with industrial refrigeration plant equipment, service and maintenance support, technical downloads and project contact.

Metalex and TH. WITT partnership in India

This is not a new catalogue relationship. Metalex’s recognition and company timeline records the TH. WITT partnership from 2002. Readers can also verify the manufacturer directly through the official TH. WITT website and review the official WITT refrigerant pump range. TH. WITT’s worldwide contact directory lists Metalex Cryogenics Ltd. as its India contact.

For a plant owner, that matters because the enquiry can begin with the refrigeration system rather than a disconnected pump model. Metalex can review the surrounding compressor, vessels, valves, controls and operating conditions together with the WITT pump duty.

Conclusion

A WITT GP51 or HRP pump should be selected from flow and head, not from plant tonnage or motor size. The strongest pump selection starts with the refrigerant duty, suction condition and complete circulation system.

For a new ammonia recirculation system or a replacement pump, use the Metalex TH. WITT product section and send the actual operating data. That gives the engineering team enough information to review the correct WITT pump family and model.