HOWDEN WRVi255 COMPRESSOR

[joanna]

HELLO EVERYONE:
My company buy a howden WRVi255 compressor.but it has two oil injection port on inlet end bearings.I don't know which I should connect.both or only one.Who can help me
? my email is zhouweidl@sina.com

[Magoo]

Contact your compressor supplier and demand detailed piping schematics for application. Alternatively google howden web site and get correct information.

[Sandro Baptista]

HELLO EVERYONE:
My company buy a howden WRVi255 compressor.but it has two oil injection port on inlet end bearings.I don't know which I should connect.both or only one.Who can help me
? my email is zhouweidl@sina.com

Maybe one of them is for the economizer.

[RANGER1]

Joanna best follow Magoo's advice,
Howden WRVI has a connection for suction end & discharge end main bearingsa on each side of compressor.
It is usually only necassary to connect to 1 suction end & 1 discharge end bearing cnnection.
The connection size is from memory 3/8", so tube connection should be 1 or 2 sizes bigger (1/2" or 3/4")

You can connect to all 4 bearing connections if you want too as they are there for practical reasons for manufacturing compressor & package design. Our company of late use all 4 connections with no problems.
However it is recommended all 4 be connected if refrigerant is Propane as flashing of refrigerant in oil can occur with it due to any pressure drop.
There are 2 off 3/4" oil injection ports as well next to each other on compressor drive rotor side, which should be used on Ammonia & most refrigerants, but in some cases its not necassary propane, R22 etc so need to check with Howden.
Oil injection line normally install regulating valve commom to both connections to regulate oil flow (usually orifice in these port connections 5.5mm screwed into compressor body already installed by Howden).
Economizer port is on non drive rotor side which is a bolted flange connection approx 50mm or 2".




What refrigerant are you using?

[joanna]

Thank you all very much!
My company use two type howden compressor.First is WRVi255,the refrigerant is R22.evaporation/condensing temperature is -10/40℃.Another is WRVi365, evaporation/condensing temperature is -40/40℃.

Our company install regulating valve on both oil injection line to regulate oil flow. If the restrictions has already be installed by Howden,should we needn't install the reaulating valve?If the pressure ratio is not high.can I not connect the oil inject port.

I am afraid the oil are all injected to the injection port and the bearings has not enough oil if the oil pump is not big enough.

[RANGER1]

A regulating valve on oil injection(if oil injection is required) is a good idea even with factory orifices.
Howden recommend a big "header" for all oil lines to come off feeding oil into compressor.

Howden or supplier should be able to advise what the oil flow is & if oil injection is required as well as its oil flow.

[Josip]

Hi, Joanna


Pumped pressure lubrication is required for both the inlet and outlet end hydro-dynamic radial sleeve bearings and also the slide valve load/un-load cylinder connections.

The inlet bearing connection(s) internally supplies oil to the shaft seal, the inlet sleeve bearings and the inlet end thrust balance piston.

The outlet bearing connection(s) internally supplies oil to the outlet sleeve bearings, the male and female rotor thrust bearings and the outlet end thrust balance piston.

The main oil injection connection supplies the rotor cavity oil for compression cooling.
A separately driven gear type oil pump supplies positive oil pressure from a retention oil supply. Manifold oil pressure is maintained at a positive differential pressure above compressor discharge pressure, 2-4.5 bar, by the higher oil pump flow delivery than compressor consumption, by-passing the excess oil pump flow through a differential pressure control valve, back to the oil reservoir.

The lubricating oil draws from the sump/reservoir through an oil pump strainer and it is pumped with the excess pump quantity piped to a by-pass regulator to produce the design oil pressure differential above discharge gas pressure measured at the compressor manifold. An oil discharge check valve is applied downstream of the oil pump to maintain the oil supply lines primed in the off cycle. After the oil is externally cooled it then passes through a full flow micronic oil filter and the clean, cooled oil then enters the oil manifold, from which all compressor supply connections receive pressurised oil.

The main oil injection consumption rate is self-regulating over all compression ratios. A manual throttling valve is permitted on main oil injection to fine tune the discharge temperature range or decrease injection quantity. Automatic regulating valves are recommended on main oil injection to maintain discharge temperature at a constant set point where discharge dew-point control is required in the oil separator. The main oil injection piping is not required on specific applications, typically heavy gases, providing the discharge temperature is not excessive under all operating conditions. This can be evaluated on the computer selection-rating program.The hydraulic slide valve actuator is also fed with pressurised lubrication.

Valves are not permitted to interrupt or jeopardise oil pressure on inlet and outlet bearing connections after the manifold with the compressor in operation.

A manual throttling valve is permitted on main oil injection to fine tune the discharge temperature range or decrease injection quantity.

It is essential that small bore piping and/or reduced bore fittings are not used between the compressor and the oil manifold. It is not permitted to restrict the oil flow and/or oil pressure to the compressor bearing connections and the oil manifold. Pressure drop between the oil manifold and compressor must be negligible for balance pistons, sleeve bearings and shaft seal. The inside diameter of the piping must be never less than the connection size on the compressor, eg, where the connection size is ½” BSP, piping with a minimum diameter of ½” must be used.
Each bearing supply connection must have a separate supply line from the manifold, ie, no branching is allowed with bearing connections. Main oil injection requires a separate supply line from the manifold, however branching is permitted on casings with 2 main oil connections.


Anyhow the best is to request help from your local Howden supplier .... to give you drawings with piping for your application ....


Hope this will be of some help ...

Best regards, Josip