This disclosure relates generally to control valves and, more particularly, to rotary valve actuation lever apparatus having interchangeable shaft adaptor inserts.
Process control plants or systems often employ rotary valves, such as ball valves, butterfly valves, eccentric-disk valves, eccentric-plug valves, etc., to control the flow of process fluids. In general, rotary valves typically include a fluid flow control member disposed in the fluid path and rotatably coupled to the body of the rotary valve via a shaft. Typically, a portion of the shaft extending from the rotary valve is operatively coupled to a stem of an actuator (e.g., a pneumatic actuator, an electric actuator, a hydraulic actuator, etc.) of the rotary control valve.
To couple the actuator stem to the valve shaft, a lever or lever arm is typically employed. The lever converts a linear displacement of the actuator stem into a rotational displacement of the valve shaft. Thus, rotation of the lever causes the valve shaft and the flow control member (e.g., a disk, a ball, etc.) to rotate to increase or restrict the flow of fluid through the valve. In operation, a controller may be used to control the displacement of the actuator stem to rotate the lever and the valve shaft and, thus, the flow control member of the valve to a desired angular position to achieve a desired fluid flow through the rotary valve.
Many known valve shafts provide a splined end for connection to an actuator via, for example, a lever as described above. Splined shafts provide a connection to evenly distribute torque load and prevent slippage or lost motion, which can improve throttling performance of a valve. While many valve shafts employ a splined connection, many other valve shafts have an end portion providing a different geometry such as, for example, a square end portion, a double-D end portion, a keyed end portion, etc.
In cases where a lever arm or lever is used to couple a linear actuator stem to a rotary valve shaft, the lever is typically specifically configured to receive an end of the valve shaft (i.e., a square valve shaft requires a lever configured to receive a square valve shaft). Thus, different levers are often required to couple to valve shafts having differently shaped ends such as those described above. The need for a number of different levers to couple to the various types of valve shafts can significantly increase manufacturing and inventory costs.
In one example, an insert member for use with a rotary valve lever includes a body having a splined outer surface and an aperture that is shaped to receive a shaft of a valve.
In another example, a lever apparatus for use with a rotary control valve includes a lever arm to rotatably mount to a stem of an actuator. The lever apparatus further includes a first opening having a first splined inner surface to receive a splined valve shaft and a second opening adjacent the first opening and having a second splined inner surface to receive at least a portion of an insert member having a splined outer surface.
In yet another example, a rotary control valve apparatus includes a housing and a valve mounted to the housing and having a shaft. An actuator member is disposed within the housing. A lever is rotatably coupled to the actuator member and has a first aperture with a first splined inner surface. The lever further includes a first end having a second aperture with a second splined inner surface to receive at least a portion of an insert member having a third aperture and a splined outer surface.
In general, the example lever apparatus described herein can be used with rotary control valves. Known lever arms or levers such as, for example, the lever 106 shown in
In contrast to known lever arms or levers, the example lever apparatus described herein can couple to various or multiple types of valve shafts. In particular, the example lever apparatus described herein can receive either a splined valve shaft or, alternatively, a square stub shaft, a double-D stub shaft, a keyed stub shaft, etc. via an insert member or shaft adaptor that adapts the lever to receive the shafts.
Rotatably coupling a lever to a splined valve shaft can prevent slippage or lost motion, which can otherwise occur when a lever is connected to a non-splined shaft, thereby improving throttling performance of the valve. Furthermore, the example lever apparatus described herein reduces manufacturing and inventory costs by eliminating the need to manufacture and inventory various types of levers configured to receive various types of valve shafts such as those described herein.
Before describing the example lever apparatus in greater detail, a brief description of a known rotary control valve assembly 100 is provided below in connection with
Referring in detail to
The actuator 102 includes a casing 114 that captures a diaphragm 116 between an upper casing portion 115 and a lower casing portion 117. The casing portions 115 and 117 are coupled together with a plurality of threaded fasteners 118 spaced along an outer edge of the casing 114. The diaphragm 116 separates the space within the casing 114 into a control pressure chamber 120 through which a controlled pressure is supplied via an inlet port 122 to displace the diaphragm 116. A diaphragm plate 124 provides a rigid backing for the diaphragm 116 and couples the diaphragm 116 to an actuator stem or rod 126 (e.g., via threads). An actuator spring 128 surrounds the actuator stem 126 and is positioned between the diaphragm plate 124 and a spring seat 130. The spring 128 provides a biasing force against the diaphragm plate 124 to return the actuator stem 126 and the flow control member 112 or other operator coupled to the actuator stem 126 to a known position in the absence of a control pressure applied to the diaphragm 116. The actuator stem 126 may include a rod end bearing 132 to rotatably couple the actuator stem 126 to a lever arm 134 of the lever 106. The housing 104 of the rotary control valve assembly 100 contains the lever 106 and, as most clearly shown in
Referring to
As discussed above, the position of the flow control member 112 is controlled by the actuator 102 via the lever 106, which is coupled to the valve shaft 142. As most clearly shown in
In operation, the rotary control valve assembly 100 receives a control signal such as, for example, compressed air in the control pressure chamber 120 via the inlet port 122. The compressed air displaces the diaphragm 116 and the diaphragm plate 124 against the spring 128. The displacement of the diaphragm 116 results in a corresponding linear displacement of the actuator stem 126. The linear displacement of the actuator stem 126 is converted into a rotational displacement of the lever 106, whereby rotation of the lever 106 causes the valve shaft 142 and the fluid control member 112 to rotate to a desired angular position to vary or control the fluid flowing through the rotary valve 110.
Although the rotary control valve assembly 100 of
The lever 200 includes a lever arm 202 having an aperture or mounting hole 204 therethrough to rotatably couple the lever 200 to an actuator stem or rod 502 (
The lever 200 can have an opening or aperture 206 substantially near the center of the lever 200. The opening or aperture 206 may include a splined inner surface 208 to receive and/or mate with a splined valve shaft such as, for example, a valve shaft 300 depicted in
The example lever apparatus 200 may also include a first end 220 and a second end 222. Each of the first 220 and the second 222 ends may include an opening or aperture 224 having a diameter that is larger than the diameter of the opening or aperture 206. The opening or aperture 224 can have a splined inner surface 226 to receive and/or mate with at least a portion of an insert member or shaft adaptor 400 of
The example lever apparatus 200 may be made of various materials such as steel, aluminum, or any other suitable material and formed via any process(es) such as, for example, machining, injection molding, etc. The splined inner surfaces 208 and 226 may be parallel keyed splines, involute splines, crown splines, serrations, etc., and may be formed via broaching, shaping, etc., or any other suitable process(es).
As discussed above,
The example insert member or shaft adaptor 400 illustrated in
In the example illustration, at least a portion of the insert member or shaft adaptor 400 is inserted into the recessed opening or aperture 224 of the first end 220 of the lever 200. The splined outer surface 402 of the insert member 400 mates with and/or engages the splined inner surface 226 of the recessed opening or aperture 224 of the lever 200 to couple the insert member 400 and the valve shaft 406 to the lever 200 such that rotation of the lever 200 rotates the valve shaft 406 and, thus, a flow control member (e.g., the flow control member 112) of a rotary valve.
The insert members 400 and 401 may be made of various materials such as steel, aluminum, or any other suitable material and manufactured via any process(es) such as, for example, machining, injection molding, etc., or other suitable forming process(es). The splines of the outer surfaces 402 and 403 may be configured as parallel keyed splines, involute splines, crown splines, serrations, etc., and may be formed via broaching, milling, hobbing, etc. or any other suitable process(es).
Referring to
In operation, the rotary control valve assembly 500 receives a control signal such as, for example, compressed air, to displace a diaphragm (e.g., the diaphragm 116 of
When the lever 200 is connected to the valve shaft 300, the splines 208 of the lever 200 engage the splines 302 of the valve shaft 300. This clamped spline connection enables the lever 200 to rotate the valve shaft without slippage or lost motion, which improves throttling performance of the valve. Similarly, when the lever 200 is connected to the valve shaft 406 via the insert member or shaft adaptor 400, the splines 226 engage the splines 402 with a gradual interference fit to minimize slippage or lost motion and improve throttling performance of the valve as the lever 200 rotates the valve shaft 406.
The example lever apparatus described herein can advantageously receive a splined valve shaft or, alternatively, an insert member or shaft adaptor that adapts the lever to receive a square shaft, a double-D shaft, a keyed shaft, etc. In this manner, the example lever apparatus described herein eliminates the need to manufacture and inventory various types of levers configured to receive various types of valve shafts such as those described herein, which may reduce manufacturing and inventory costs.
Although certain apparatus have been described herein, the scope of coverage of this patent is not limited thereto. To the contrary, this patent covers all apparatus fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.