PNEUMATICALLY-DRIVEN PUMP Russian patent published in 1998 - IPC

FIELD: manufacture of pumps; handling liquid media including aggressive media. SUBSTANCE: pump includes housing 1 with central partition 2, diaphragms 3 and 4 connected by rod 5 forming diaphragm unit. Diaphragms 3 and 4 separate chambers 6 and 7 from pump chambers 8 and 9; spool valve 18 of distributing device is located in cylindrical bore of housing 1. Ends of spool valve 18 have different areas. Chamber 19 is formed under end having lesser area and chamber 20 is formed under end having larger area. Chambers 6 and 7 are brought in communication by means of passages 23 and 24 provided with distributing device. Passages 25 and 26 bring chambers 6 and 7 in communication with atmosphere by means of spool valve 18. Chambers 19 and 20 are brought in communication with supply main 29 via passages 27 and 28. Throttle valve 30 is mounted in passage 28. Partition 2 is provided with control device made in form of auxiliary spool valve 31 with bore 32. Spool valve 31 has two fixed positions. Chamber 20 is brought in communication with atmosphere through passage 36, bore 32 of spool valve 31 and passage 37. EFFECT: enhanced reliability. 4 dwg