PDA

View Full Version : Commissioning Bitzer Screws







Andy
21-11-2006, 12:19 AM
Hi Guys:)

I have a rack to start up using OSN7471 Bitzer screws, anyone experienced any problem when starting these up:)

Kind Regards Andy:)

Pooh
21-11-2006, 01:59 AM
Andy
what ever you do dont run them backwards as the thrusts only work one way and if they run backwards very quickly the rotors weld themselves to the end plate. I have one that I have sectioned for demonstration purposes that the discharge check valve had stuck open on causing it to run the wrong way and it took a twenty tonne press to get the rotas out. Other than that check the oil flow valves are in the correct way round and all should be OK.

Ian

NoNickName
21-11-2006, 08:48 AM
They work pretty flawlessly. Make sure the intermittent solenoid valve is operated correctly to ensure oil spray in the chambers.

Andy
21-11-2006, 09:43 PM
They work pretty flawlessly. Make sure the intermittent solenoid valve is operated correctly to ensure oil spray in the chambers.

Hi Nick:)
is this the unloading solinoide:) or the oil injection

Kind regards Andy:)

NoNickName
21-11-2006, 10:12 PM
Hi Nick:)
is this the unloading solinoide:) or the oil injection

Kind regards Andy:)

Neither. There are 4 solenoids, from CR1 to CR4. Depending on the configuration (modulating or steps), cr1 to cr3 are devoted to the capacity regulation, while cr4 is intermittent to ensure constant oil spray in the slider chamber.
Pulses should be 10s ON, 10s OFF, and so on forever.

Andy
21-11-2006, 11:03 PM
Hi Nick:)

you got me thinking when you mentioned CR4, so I checked the bitzer web site:)
You must be talking about the compact screw used on chillers:) Our screw is an open type on blast freezing, with only CR1 and CR2.
I agree that the bitzer screw is a very good compressor;)

Kind Regards Andy:)

NoNickName
22-11-2006, 10:12 AM
Oops sorry, wrong model.