Screw compressor, do you have to buy a new one???

[Boaz]

Hi All.
I am new to this forum.
As a compressor rebuilder, first I looked for information regarding rebuilding, especially material concerning rebuilding of screw compressors – with no luck.
After asking some of the forum members, I found that screw compressor rebuilding does not exist in many parts of the world.
Since our company is rebuilding them for more then 30 years, I would like to invite forum members to write questions and would be very happy to contribute from my experience.
We rebuild: Trane, Carrier, York, Bitzer, Hitachi, Howden, Mycom…

Please feel free to contact me.

[GHAZ]

hi boaz i rebuild screw and recipe compressors on site mainly ,and my favourite are the hitachi screw but i always struggle with slide valve piston seal ,because the o ring fits easey but the top plastic seal seems to be smaller and tighter to put on and sometimes it takes a 30 minutes , is there any better way of putting it on.

[Boaz]

Dear Ghaz.
This problem is well known. We rebuild the compressors in our shop, as it is impossible to do anything more then replace winding or - as you have mentioned - take care of the unloader piston.
However, When a customer is calling with a piston that does not move, we do try to replace it on site. For that we keep a few in our shop, so the technitian does not need to do it in the field. I would recommend to buy a new piston from Trane, or buy a damaged old compressor to take the piston from. Just be carefull: Do not put the new "O" ring before completly cleaning the piston from oil, because when touching the oil the "o" ring "drinks" the oil and blow, which can cause big problems with fitting to the cylinder on site.
Regarding the "plastic" cover: no magic here, but do it again and again untill you reach this magic touch... and as mentioned before: doing it in your free time of your shop is very much recommended. Hope this helps.