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Matheson 6295 Series Operating Instructions

Excess flow valves

Operating Instructions for Matheson 6295 Series Excess Flow Valves

1. General

1.1 This excess flow valve is designed to provide automatic shut off of gas flow

under failure conditions which cause a flow in excess of the valve rating.

1.2 A provision for higher purge flows is provided for purging without nuisance shut

off.

1.3 The valve is a ¼ turn valve, providing two positions - AUTO and OPEN

(RESET). The valve handle is provided with cutouts which line up with a label

on the valve bonnet.

2.1 Only personnel trained in pipe or VCR fitting connections should install the EFV.

2.2 After installation, leak checking is required to prevent leaks of dangerous gases.

3.1 If purging with an inert gas is desired, turn the handle so that the cutouts line up

with OPEN (RESET) on the bonnet label. In this position, the valve is locked

open, and will not shut off regardless of the flow rate. See Figure 1.

NOTE: DO NOT OPERATE THIS VALVE IN THE OPEN (RESET) POSITION WITH

ANY DANGEROUS GASES.

WITH INERT GASES, OR FOR RESETTING THE VALVE AFTER A SHUTOFF

DUE TO AN EXCESS FLOW CONDITION. FAILURE TO RUN IN THE AUTO

POSITION MAY RESULT IN A HAZARDOUS CONDITION.

MINT-0305-XX

Rev. B

THIS POSITION IS PROVIDED FOR PURGING

Phone: (215) 641-2700

Page 1 of 2

166 Keystone Drive

Montgomeryville, PA 18936

Fax: (215) 641-2714

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Page 1 Operating Instructions for Matheson 6295 Series Excess Flow Valves 1. General 1.1 This excess flow valve is designed to provide automatic shut off of gas flow under failure conditions which cause a flow in excess of the valve rating. 1.2 A provision for higher purge flows is provided for purging without nuisance shut off.
Page 2 3.2 To operate with process gas, turn the handle so that the cutouts line up with AUTO. In this position, the valve will automatically shut off when the flow rate exceeds the rating of the valve. See Figure 2. 3.3 Opening the cylinder valve or other process valves too quickly into a line which has a vacuum or low pressure condition compared to the pressure upstream of the EFV may cause the valve to trip due to a surge of gas into the low pressure line downstream of the valve.