US 5,474,103 A · Safety guard for orifice fitting device

Abstract

A safety guard or lockout device (22) for a dual chamber orifice fitting device (1) having a removable orifice plate (4). In a normal position when the upper and lower chambers (8, 9) are equal in pressure, the guard (50) of the safety guard device (22) is in a retracted position relative to the square end (36) of a valve gear shaft (18) as shown in FIG. 3 to permit connection of a manual tool, such as a wrench, to square end (36) of valve gear shaft (18) for actuation of isolation valve member (16). When changing the orifice plate (4), the pressure in the upper chamber (8) is reduced to atmospheric conditions and provides a fluid pressure differential between chambers (8) and (9). The fluid pressure differential moves fluid responsive member (30) and guard (50) to an extended position covering the square end (36) of valve gear shaft (18) to prevent access of a manual tool to the shaft (18) thereby preventing operation of the isolation valve (16) separating the upper chamber (8) from the lower chamber (9).

Claims9

Dependent claims

In combination with an orifice fitting device having an outer housing about a flow line, a removable orifice plate in the flow line, a pair of fluid chambers, a valve member for selectively separating said fluid chambers, and an external tool connector for said valve member for moving said valve member between an open position permitting fluid communication between said fluid chambers and a closed position blocking fluid communication between said fluid chambers, one of said fluid chambers being in continuous fluid communication with said flow line during operation of said flow measuring device;

the improvement comprising:
lockout means for said external manual operator to prevent inadvertent actuation of said valve member when the fluid pressure in the pair of fluid chambers is unequal, said lockout means including:
a body;
and
fluid pressure responsive means mounted within said body and movable between a position for blocking actuation of said valve member and a position for permitting actuation of said valve member;
said fluid pressure responsive means responsive to a fluid pressure differential in said chambers and movable to a position for blocking actuation of said valve member when a fluid pressure differential exists in said chambers, and movable to a position for permitting actuation of said valve member when the fluid pressure in said fluid chambers is equalized.

3 more elements

Lockout means for the actuating shaft of a valve member for separating a pair of fluid chambers in an orifice fitting device to permit the removal of an orifice plate in a flow line, the actuating shaft having a tool connector adjacent an end of said shaft located externally of the orifice fitting device and adapted for engagement with a suitable tool for rotation of said shaft and movement of said valve member;

said lockout means comprising:
a body extending about said shaft adjacent the tool connector on said shaft externally of the orifice fitting device;
and
fluid pressure responsive means mounted within said outer body and movable between a position for blocking actuation of said valve member and a position for permitting actuation of said valve member;
said fluid pressure responsive means responsive to a fluid pressure differential in said chambers and movable to a position for blocking actuation of said valve member when a fluid pressure differential exists in said chambers, and movable to a position for permitting actuation of said valve member when the fluid pressure in said fluid chambers is equalized.

2 more elements

Dependencies are inferred from the claim text.

Safety guard for orifice fitting device

Life of this patent

Safety guard for orifice fitting device

Life of this patent

Abstract

Claims9