Performance enhancement of open loop gas recovery process by centrifugal separation of gases

Abstract

The proposed INO-ICAL detector [1] is going to be instrumented with 28800 RPCs (Resistive Plate Chamber). These RPCs (2 × 2 m2 size) will consist of two glass electrodes separated by 2 mm and will use a gas mixture of Freon R134a, isobutane and sulphur hexafluoride (in the ratio of 95.3:4.5:0.2). An Open Ended System (OES), in which the gas mixture is vented to the atmosphere after a single passage through the detector, is most commonly used for small detector setups. However, OES cannot be used with the INO-ICAL detector due to reasons of cost and pollution. It is necessary, therefore, to recirculate the gas mixture in a closed loop. In a Closed Loop gas System (CLS) [2] the gas mixture is purified and recirculated after flowing through the RPC. The impurities which get accumulated in the gas mixture due to leaks or formation of radicals are removed by suitable filters. The Open Loop System (OLS) [3] is based on the separation and recovery of major gas components after passage of the gas mixture through the RPCs. and has the advantage that it does not need filters for removal of impurities. However a CLS is found to be more efficient than OLS in the recovery of gases in the mixture. In this paper we discuss centrifugal separation [4] as a technique to extract major gas constituents and use this technique to improve the efficiency of OLS. Results from preliminary trial runs are reported.