compressor question

[TED C]

I am starting to rebuild/restore a compressor, one of the first tasks was removing old fittings from the receiver, one of these fittings was connected to a small pipe 5/16 i.d. The position of the fitting on the receiver is about 1 o clock therefor the pipe runs at a angle almost to the bottom of the tank, it is not the standard outlet. Any why the extension and would there a reason for the angle?
Regards
Ted

[malb]

Is the small tube the only thing that connects to the fitting or is their another connection point maybe 1/2in or slightly larger.

Was the unit fully assembled when you received it or partly dismantled?

The delivery tube from the compressor head to the receiver is normally 1/2in or larger and goes to a check valve that screws into the receiver . The check valve normally also has a fitting for a smaller bleeder tube that goes to the pressure switch that controls when the motor starts and stops. When the motor stops because there is sufficient pressure in the tank, the switching mechanism also opens a port and lets the air in the delivery tube escape via the smaller tube (the short sharp hiss you hear when a comp shuts off).

This leaves the delivery tube at atmospheric pressure and makes it easier for the motor to restart next time, as it can establish rotation before it is working against a substantial load. (For a belt drive the belt reduction is typically around 4:1 and the compressor can turn over a few times before it creates an obstructive pressure in the delivery tube, so the motor gets maybe 20 turns or so with light load to establish rotation.

The air in the receiver does not purge through the pressure switch because the check valve only allows air to pass from delivery tube to receiver, and not the other way.

I suspect that the fine tube you refer to is the bleeder tube. This would almost definitely be the case if the fitting can also accept the delivery tube. As to why the bleeder points toward the floor, I can only assume that the fitting has been removed and reinstalled at some time and been left out of orientation. Direction sensitive fittings like the check valve are normally installed with a sealant and adjusted to point in the required direction, rather than being fully tightened with a tape or similar providing the seal.

Hope that helps, if not some photos etc might be useful.

[TED C]

Malb,
Thanks for the reply.
The tube was not connected to anything, although there us a fitting on it, it is at the other end of the receiver to the check valve, the check valve has no 'take off ports', the electric motor cut out is a separate unit.
I have been reading about bleeder/blow down valves in the last day or two, from what I can see it does not have one.
The compressor is an old Ross unit driven by a 2 horse three phase motor.

Bloody hell, I had a shocker in the last sentence of the original post.
Regards
Ted