Description of WRV, WRVi compressors

The Howden WRV and WRVI oil-injected compressor is a volumetric rotary machine filled with oil with controlled power.

Compression is achieved by combining two screw rotors on parallel shafts installed in the crankcase.

Properly machined screw rotors are called “dad” and “mom”. The “dad” (leading) rotor has four cams, which are combined with six grooves in the “mother” (slave) rotor. At the same time, both rotors have the same outer diameter. Each rotor is supported by two thick-walled white metal sliding bearings mounted next to the compression chamber. Angular contact bearings unloaded by internal discharge drums have an axial thrust load.

Power control is achieved using a hydraulically controlled spool in the compressor. This ensures internal gas recirculation, thereby controlling power from 100% to nominal 10% while saving energy.

There are various ways to control the hydraulic cylinder. Before performing any work with this equipment, you should also review the relevant literature provided by the compressor unit supplier.

DESCRIPTION OF THE GAS SYSTEM OF A TYPICAL COOLING COMPRESSOR UNIT

The gas is supplied to the compressor through a check valve, then the filter is installed directly on the inlet flange and descends into the oil tank/separator. A check valve is necessary so that the compressor does not “rotate” in the opposite direction when it stops at high gas pressure at the outlet.

If necessary, a second check valve is located at the tank outlet to prevent the penetration of gas or liquid refrigerant.

The primary separation of the oil-gas mixture is carried out in the tank, the secondary separation is carried out in a rigid wire separator element near the tank outlet.

In some separator designs, the wire mesh is changed to a separation cartridge.

The separated oil is drained into the oil tank. It is also possible to install an additional secondary separation vessel, and very high separation efficiency is required. The separated oil is usually drained into the compressor through a pipe with a small opening, which can be equipped with a protective filter and a shut-off valve.

DESCRIPTION OF THE OIL SYSTEM OF A TYPICAL REFRIGERATION COMPRESSOR UNIT

Pressurized oil at the outlet is removed from the tank by an oil pump, passes through the radiator and fine filters to the manifold, where it is supplied to the bearings, the discharge drum, the shaft seal, the compression chamber and the hydraulic drive.

When using liquid refrigerant injection, the oil cooler is not used.

The differential pressure reducing valve installed in the system in front of the filters maintains the manifold pressure in the range of 30 lbf per square meter (2 kg/cmi) for standard compressor units and 40 lbf per square meter (2.7 kg/cmi) for type 'H' compressor units. When the compressor is operating in continuous mode, it is possible to install double fine filters, which allow replacing one filter element while the other is operating.

LUBRICATING OIL SPECIFICATION

This type of Howden compressor is equipped with neoprene O-rings.

The O-ring seal material is designed to work in most types of refrigerants and oils, but the compatibility of a combination of all types of refrigerants and oils is not guaranteed.

If you have any questions about this issue, contact Toros for advice on the cost of any special-purpose ring seals.

STANDARD REFRIGERANT TYPES:

R717, R22, R134a, R404A, R407C, R410A, R507

STANDARD OIL TYPES:

Mineral oil
High molecular weight essential oil
Polyalkylene glycol oil
Alkylbenzene oil

For most ammonia refrigerants, an acceptable viscosity value is 68 cSt at 40°C. However, other types of refrigerants, such as R134a, which have a high condensation temperature, or for use in hydrocarbon gas environments, require the choice of special types of oil.

Toros offers its customers consulting services on the type of oil compatible with a specific type of refrigerant or gas.

Howden compressors

Howden XRV127 Howden XRV163 Howden XRV204 Howden WRV163 Howden WRV204 Howden WrVi255 Howden WrVi321

Technical documentation for XRV 127 compressors

XRV 127 Description XRV 127 operation Dismantling XRV 127 Assembling XRV 127 XRV 127 tools XRV 127 Parts XRV 127 schemes

Technical documentation for XRV 163-204 compressors

xrv 163-204 Description xrv 163-204 operation Dismantling XRV 163-204 XRV 163-204 assembly XRV 163-204 tools XRV 163-204 Spare Parts XRV 163-204 schemes

Technical documentation for WRV compressors - WRVi

WRV description WRV operation WRV 163 repair WRV 204-255-321 repair WRV tools WRV spare parts WRV-WRVI diagrams

All Howden parts