Browse Prior Art Database

H2-O2 Gas Safety Control

IP.com Disclosure Number: IPCOM000043682D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Cloutier, RL: AUTHOR [+2]

Abstract

A need has arisen in dry process etching to enable H2 and O2 gases to be used in the same tool but not at the same time since mixing H2 and O2 gases can cause an explosion. This article describes a valving mechanism that allows both H2 and O2 gases to be connected to the same tool at the same time but does not allow the two gases to mix regardless of any failure mode, i.e., loss of electrical power, loss of compressed air or a tool malfunction. The significant component of the design of the valving mechanism is the "delay-coupling". The mechanism (Fig. 1) consists of two manually operated bellows-type sealed valves 11, 12, with a fifteen-pound spring return (contained within the valve), a double acting-double ended air cylinder 13 and two "delay-couplings" 14, 15. Fig. 2 shows an expanded view of "delay coupling" 14. Fig.

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H2-O2 Gas Safety Control

A need has arisen in dry process etching to enable H2 and O2 gases to be used in the same tool but not at the same time since mixing H2 and O2 gases can cause an explosion. This article describes a valving mechanism that allows both H2 and O2 gases to be connected to the same tool at the same time but does not allow the two gases to mix regardless of any failure mode, i.e., loss of electrical power, loss of compressed air or a tool malfunction. The significant component of the design of the valving mechanism is the "delay-coupling". The mechanism (Fig. 1) consists of two manually operated bellows-type sealed valves 11, 12, with a fifteen-pound spring return (contained within the valve), a double acting-double ended air cylinder 13 and two "delay-couplings" 14, 15.

Fig. 2 shows an expanded view of "delay coupling" 14. Fig. 1 shows both valves 11 and 12 in a closed position with no air pressure applied to either side of air cylinder 13. (Note the positions of key-pins 16, 17 in their delay-coupling slots 18, 19, respectively.) If O2 gas is to be used (valve 12), air pressure is applied at port 2 of air cylinder 13, moving piston 20 and outer sleeves 21 of "delay- coupling" 14 to the left. When the end of valve 12's "delay-coupling" slot 18 contacts key-pin 16, piston 20 continues to the left and opens valve 12. (Note, key-pin 17 of valve 11 rides in slot 19 and the movement of piston 20 to open valve 12 has no effect on valve 11; thus, valv...