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Specialist Forums > Technical Forum > Hamworthy 3S4 compressors
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Otley
posted : January 9, 2014 Post subject: Hamworthy 3S4 compressors
Hi Im new to the forum, so hello from Yorkshire. I have a couple of compressor questions that Id appreciate some help with.

I have a couple of old (1970s) petrol driven Hamworthy 3S4 compressors that Ive been fettling and restoring. I got these to fill my 10 litre air tank that I use for my air rifle to 232bar, so the use of the compressors is very intermittent - maybe half a dozen times a year.

The filter tower serves as the moisture separator, with a condensate drain tap at the base of the tower. I think the tower is supposed to be drained every 10 minutes of operation or so. So far, I have been repacking my filters with indicating silica gel, which I regenerate by heating to 110 deg C for an hour when its weight has increased by 20% from dry. As soon as I have filled an air tank, I run the compressor for a few seconds to purge moisture from the pumps and cooler piping and then remove the filter cartridge and put it in a sealed freezer bag.

My questions:
1. The filter towers will accept new proprietary cartridges from Midland Diving Equipment. These, I believe, are filled with silica gel, activated carbon and molecular sieve, with hopcalite as an option. If I fit one of these cartridges, can I leave it in the compressor filter tower between runs, or will the drops of free water condensate that remain in the filter tower after draining wet the silica gel and molecular sieve in the cartridge? I see that the likes of Bauer claim many hours of life for their filter cartridges, especially if operated at low ambient temperatures, but arent there always free water drops in the filter housing that will wet the filter media since the air at pressure is 100% relative humidity?

2. The manual I have for the 3S4 compressor states that it should be run with the condensate drain open for three minutes prior to shutting down. When I open the condensate drain, after a few seconds I can hear the third stage free piston starting to rattle because there is insufficient back pressure to hold it against its slipper piston. I cringe when I hear the rattle, fearing that the free piston and slipper piston will be damaged with these continual impacts. Do I need to worry?

Sorry for such a long first post, but if anyone can answer my questions, Id be most grateful.

Thanks in anticipation.


 
LSM Diving
posted : January 11, 2015 Post subject: Hamworthy 3S4 compressors
Hi here just read your blog and I have just purchased the same compressor and have hunted high and low for a manual is there any chance of you sending me a copy or know where I can get any help would be much appreciated thanks

 
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