Air dryer apparatus for use with pneumatic operative device

In an air dryer apparatus use with pneumatic operative devices wherein compressed air delivered from an air compressor is stored in an air tank through a first check valve after passing through the air dryer apparatus having a purge valve on the inlet side thereof, and thus-stored compressed air within said air tank is then supplied to said pneumatic devices, and wherein the current pressure within said air tank is detected having reached either a preset upper limit level or a preset lower limit level by way of a fluid pressure governor so that the air compressor and the purge valve can be controlled on the basis of thus-detected results;

• an improvement
• (a) wherein said air dryer apparatus and said pneumatic devices are provided in communication with each other at the outlet opening of said air dryer apparatus and at the exhaust ports of said pneumatic devices by way of purging passage means;
• (b) wherein there are provided second check valve means on the way of said purging passage means in such a manner that the forward working direction thereof may be headed towards the outlet opening of said air dryer apparatus;
• and
• (c) exhaust valve means having an exhaust valve body formed integrally with the valve body of said purge valve, and adapted to operate in such a manner that said exhaust valve body is opened when said purge valve body is in a closed position, while said exhaust valve body is closed when said purge valve body reaches a preset degree of opening;
• and
• (d) wherein said second check valve means has its upstream side connected operatively to the upstream side of said exhaust valve means.