J E Hall semi- hermetic HSM screw

[blake]

anyone used the j e hall semi-hermetic screw type
HSM ,due to cost we are thinking of using a 3216 model [Rather than Bitzer HSN 7471-75]
on R404a for our new range blast freezers down to
-40c room, we will use economiser, oil sep, oil cooler etc

[Andy]

anyone used the j e hall semi-hermetic screw type
HSM ,due to cost we are thinking of using a 3216 model [Rather than Bitzer HSN 7471-75]
on R404a for our new range blast freezers down to
-40c room, we will use economiser, oil sep, oil cooler etc

Hi Blake

I have some experience with both Halls Screws and have installed quite a lot of HSN 7471 screws.
I would expect the Halls screw not to be as effecient at the lower temperature.
On the cost front I would say it is a supprise to me that the Halls screw is cheaper, I will talk to Halls about this.

Kind Regards Andy

[hva loz]

hi andy
any news,effeciency is not an issue,most customers would not know about COP or isotropic issues, they just want product frozen ASAP, we do not deal with supermarkets, its just i have not used j e hall , the price diff is quite a lot rgds blake aka hva loz

[setrad7791]

Hi there! In my experience with blast freezers screw compressors would be a bit of a risk due to the low temps, at -40 ambients your suction pressure/temp is down around -45, with screws being so dependent on oil return i would be more inclinded to go with a two stage compressor! lower cost and less installation cost, or two compressors in parallel.