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Manual Valve Actuator Manual valve actuators do not require an outside power source to move a valve to a desired position. Instead, they use a handwheel, chainwheel, lever, or declutchable mechanism to drive a series of gears whose ratio results in a higher output torque compared to the input (manual) torque. Most manual valve actuators use worm gears, mechanical devices that transmit motion between non-intersecting right-angle axes. Some manual valve actuators move rotary motion valves such as ball, butterfly, and multiturn valves a quarter-turn or more from open to close. Other manual valve actuators move linear motion valves such as gate, globe, diaphragm, pinch, and angle valves. Typically, these valves have a sliding stem that pushes the closure element open or closed. Depending on the valve’s design, the stem may rise during rotation or without rotation. The clockwise rotation of a direct-acting actuator causes the valve to close in a clockwise direction. By contrast, the clockwise rotation of a reverse-acting actuator causes the valve to close in a counter-clockwise direction. Selecting manual valve actuators requires an analysis of performance specifications. Manual actuators for rotary valves vary in terms of actuator torque and range of motion. Torque, the measure of force needed to produce rotary motion, is determined by multiplying the applied force by the distance from the pivot point to the point where the force is applied. Common ranges of motion include 90° (quarter-turn), 180°, 270°, and 360° (multi-turn). Manual valve actuators for linear valves differ in terms of valve stem stroke length, number of turns, and actuator force or seating thrust. Typically, stroke length is measured in inches (in) while actuator force is measuring in pounds (lbs). Other important specifications for manual valve actuators include stem diameter and, when applicable, handwheel diameter. Manual valve actuators are often housed in enclosures that are rated by the National Electrical Manufacturers Association (NEMA), a trade organization which defines safety standards for electrical equipment. Type 4 NEMA enclosures are rated for indoor and outdoor use and provide protection from falling dirt, rain, sleet, snow, windblown dust, splashing water and hose-directed water. Type 4X NEMA enclosures provide protection against these same environmental variables and can also resist corrosion. Type 7 NEMA enclosures are constructed for indoor use in hazardous locations categorized as Class I; Division 1; Groups A, B, C, or D in NFPA70, a directive from the National Fire Protection Association (NFPA). Type 9 NEMA enclosures are constructed for indoor use in hazardous locations classified as Class II; Division 1; Groups E, F, or G in NFPA70. knife manual sharpener, manual optoelectronic, manual smacna, manual actuator, manual valve actuator, otdr manual, chaplet manual, gsm 4200 manual, racal 6113 manual, valve actuator manual, valve manual actuator, smacna manual, actuator manual valve, actuator valve manual, knife sharpener manual Air Valve Air valves allow metered flow of fluid in one or both directions. Many of them allow for free flow in one direction and reduced or metered flow in the reverse direction. They are used in pneumatic circuits to regulate the rate of activation or exhaust of cylinders and other pneumatic devices. Air valves can be configured in-line or at right angles. In an in-line configuration the input and output ports are on the same axis. In a right angle configuration the input and output ports are perpendicular. Flow control choices for air valves include unidirectional (one-way), bi-directional (two-way) or three-way. In a one-way configuration the valve permits metered (restricted) flow in one direction and free flow in the reverse direction. In a two-way configuration the valve provides for metered (restricted) flow in both directions. In a three-way configuration the control provides flow control in three directions. Flow compensation is an important consideration. Choices include noncompensated, pressure compensated, and temperature compensated. In a noncompensated flow control the amount of flow that passes through the orifice and the pressure drop across it are directly related. Flow through the valve varies with the fluid viscosity and pressure across the valve. A pressure compensated flow control maintains accurate output flow regardless of the input pressure, up to rated limits. The orifice is adjusted to compensate for pressure variations and maintain a set flow rate. A temperature compensated flow control maintains accurate output flow regardless of the input temperature, up to rated limits. Sharp-edged orifices or expansion rates of dissimilar metals are used to maintain a constant flow rate. Air valves may have adjustability. Choices include adjustable flow or fixed flow. Important performance specifications to consider include metered flow for gas or air, and maximum operating pressure. Common features for air valves induce integral relief valve, integral bypass, integral check valve, meter in, meter out, tamper-proof, locking nut, and swivel. An integral relief valve is pressure limiting. An integral bypass controls by diverting or bypassing excess flow. A check valve offers resistance to flow in only one direction. If the flow inlet to the actuator is controlled, it is a meter-in system. If the actuator outlet is controlled, it is a meter-out system. Tamper-proof controls have a feature such as a removable knob or lock to prevent inadvertent or unauthorized adjustment. A locking nut on adjustment stem locks the metering setting. Swivel air valves rotate or swivel for alignment on cylinder in any orientation. Media choices include air, gas, and steam. Mounting choices for air valves include cartridge, subplate or manifold, pipe or line mount, port mounted, or stacked or sandwich mount. Additional specifications to consider when searching for air valves include metered flow input connectors, free flow input connectors, adjustment, and operating conditions. Related keywords: flow control, pneumatic control, idle air control valve, temperature control device, idle air control, control flow valve water, what controls air idle, control valve importer, control valve exporter, idle control valve, american flow control, control heater valve, air control valve, temperature control valve, air control idle motor Details of Orbit Valve        3. DESIGN OF ORBIT VALVE 3.1 General description. 3.1.1 Valve Type All of the Orbit valve is classified as rising Stem, trunnion mounted Ball Valve with single stationary Seat and bubble tight bidirectional seal. 3.1.2 Valve Model All the valves in Complex A is using Orbit's Standard model. 3.1.3 Valve Figure Number (eqv. to part no.) There are 2 major Figure Number available in Complex A. Figure Number: 1423H6L -78 units Figure Number: 1433H6L -207 units The other Figure Numbers are: 1233H8L, 1133H8L, 1123H8L & etc. From the Figure Number imformation such as Model, Class, Port Size & Connection, Trim and Suffix shall be identified. (in the order) In general all the above were common in the folowing specification : Standard Model, Standard Trim (T3) and comes with Actuator. The difference is on the Class (ANSI300/ANSI600), Port Size (Full/Reduced Port) and Packing (injectible Graphite -600degF /OS&Y Model -800degF).        CHECK VALVE FAILURE  CHECK VALVE FOUND PASSING AND CAUSED BACK FLOW WHEN THE PUMP TRIPPED As removed condition, it was found that the check valve disc [flapper] was not closing fully, leaving a opening at the bottom of the disc [disc should be vertical when it is closed, but found tilted slightly thus preventing it from closing fully against the seat] Lifted the disc manually and adjusted to close properly. it is observed that the disc and the seat are not in a same centre line Disc seating surface found not properly lapped before. was not sufficiently built up earlier leaving a long under cut on the surface caused 1. Disc was not properly aligned during servicing [The bore of the hinge was rebuilt and machined. during machining, the centre line was not maintained properly] 2. The stopper on the disc to keep the disc vertical was not properly fabricated 3. Disc machining to maintain the sealing surface was not done properly Note: Operation of the check valve after servicing at vendor shop was not witnessed Only leak test was witnessed Gate Valve Gate valves should only be considered for remotely operated on-off applications, where a fail-safe action is not required. They are normally equipped with an electric actuator or hydraulic actuator. Typical applications are storage tank isolating valves, remotely operated on/off valves on blenders, pump suction shut-off services, and shut-off services on wellheads in oil and gas production facilities. For gate type control valves, the same requirements shall apply as for gate on-off valves, Globe Valve Two-way globe valves If rotary valves cannot be used, globe valves should be considered as the first choice Three-way globe valves Each flow path shall be sized separately for three way globe valves Except for instrument air dryers, the application of three-way globe valves requires the approval of the Principal Butterfly Valve Butterfly valves shall be considered for the following circumstances: - If the required size would make it economically attractive (usually due to a high flow rate with a low pressure drop.
- If eccentric plug/segmented ball or globe valves are not suitable
- For corrosive services, where body lining of globe valves becomes economically unattractive.
Double or triple eccentric butterfly valves, also known as high performance (HP) butterfly valves, can be used in Class V or VI TSO applications in accordance with IEC 60534-4. They can handle high temperatures and high differential pressures. Ball Valve Ball valves shall be considered for on-off service Ball valves for use in erosive (e.g. slurry) service etc. should be equipped with a scraper type of seat construction Ball valves, i.e. valves without specially designed control related internals, shall not be selected for throttling service without the approval of the Principal. Unless equipped with a special trim, i.e. anti-cavitation or low-noise design, certain ball valves may be unsuitable for high differential pressures. Control Valve General
If the application allows, valves with a rotating spindle are preferred to linear motion valves for reasons of: - Robustness
- Capacity
- Turndown
- Fugitive emission
Control valves shall be selected in accordance with the requirements of the piping class. Cadmium plating or galvanizing shall not be used for any component of the valve assembly or its accessories. Valve Plug Guiding Top and Bottom GuidedValve plug is aligned by guide bushings in the bonnet & bottom flange High stability and minimum deflection (high pressure drop applications) Cage GuidedValve plug is guided by a cylindrical cage throughout the travel range Increased trim life & lower stem friction (high pressure drop applications) Steam, gas and clean liquid applications only Stem GuidedValve plug is aligned with the seat ring by a guide bushing in the bonnet commonly used for throttling applications Top and Port GuidedValve plug is aligned by a guide bushing in the bonnet or body and also the port CavitationA two-stage phenomenon of liquid flow. The first stage is the formation of vapor bubbles within the liquid system due to static pressure of fluid falling below the fluid vapor pressure; the second stage is the collapse or implosion of these cavities back into an all-liquid state as the fluid decelerates and static pressure is recovered Choked flowA condition wherein the flow rate through a restriction does not increase when the downstream pressure is decreased at a fixed inlet pressure. Electrohydraulic actuatorA device that converts electrical energy to hydraulic pressure and into motion. Extension bonnetA bonnet with a packing box that is extended above the usual height so to maintain the temperature of the packing within its operating limits. Fail-ClosedA condition wherein the valves closure member moves to a closed position when the actuating energy source fails. Fail-OpenA condition wherein the valve closure member moves to an open position when the actuating energy source fails. Fail-SafeA characteristic of a valves and its actuator, which upon loss of actuating energy supply, will cause a valve closure member to be fully closed, fully open, or remain in the last position, whichever position is defined as necessary to protect the process. Valve  Definition A final controlling element, through which a fluid passes, which adjusts the size of flow passage as directed by a signal from a controller to modify the rate of flow of the fluid. Valve body - A housing for internal parts having inlet and outlet flow connections Bonnet - The part of the body assembly which serves as a means for mounting the actuator Cage - A hollow cylindrical trim element that is a guide to align the movement of a valve plug with a seat ring. Seat - The portion of the valve body where the valve plug contacts for closure. Valve Plug - A movable part which provides a variable restriction in a port. Valve Plug Stem - A rod extending through the bonnet assembly to position the valve plug. Trim - The internal parts of the valve which are in contact with the controlled fluid Port - A fixed opening inside the diameter of the seat ring through which the fluid passes Packing Box - The part of the bonnet assembly used to seal against leakage around the valve plug stem  Actuator An air operated mechanical device used to open and close or modulate a valve. The actuator is designed to convert air pressure into mechanical force sufficient to operate the valve. Diaphragm - A flexible pressure responsive element which transmits the force to the actuator stem Actuator stem - The extension of the diaphragm plate or piston for connection to the valve plug stem Actuator spring - The spring enclosed in the yoke is to move the actuator stem in a direction opposite to that created by the diaphragm pressure Piston - A movable pressure responsive element which transmits force to the operating fluid Solenoid Valve  Solenoid Valve An electro-magnetically operated valve which enables electrical control of the air supply to a pneumatic actuator Applications General Service Severe Service Steam Service Cryogenic Service Anti-surge Sizing & Selection Datasheet Material Selection Codes & Standards Sizing for Valves Sizing for Actuator Actuator  Valve ActuatorAn air operated mechanical device used to open and close or modulate a valve. The actuator is designed to convert air pressure into mechanical force sufficient to operate the valve. Diaphragm - A flexible pressure responsive element which transmits the force to the actuator stem Actuator stem - The extension of the diaphragm plate or piston for connection to the valve plug stem Actuator spring - The spring enclosed in the yoke is to move the actuator stem in a direction opposite to that created by the diaphragm pressure Piston - A movable pressure responsive element which transmits force to the operating fluid Yoke - The structure by which the diaphragm case is supported rigidly on the bonnet. Travel Indicator - A pointer to indicate the travel of the valve plug. Travel indicator scale - A graduated scale attached to the yoke for indication of the travel. Valve Flow Coefficient (Cv) - The number of US gallons per minute of 60°F water that will flow through a valve with a one pound per square inch pressure drop Rated Cv - The value of Cv at the valve full-open position Rated Travel - The linear movement of the valve plug from the closed position to the valve full - open position Leakage - The quantity of fluid passing through an assembled valve when the valve is in the closed postion On-Off Service - When the valve is used to start / stop the flow by being cycled to the full open or to full closed position Modulating Service - When the valve is being used to throttle or regulate the flow by varying the opening between open and closed positions Maximum shut-off Pressure - The pressure of the fluid flowing into the valve against which the valve will have to close Service Temperature - The maximum and minimum temperature of the media Supply Pressure - The plant air supply pressure available to operate a pneumatic actuator Stem Torque - The force required at the valve stem to open or close the valve against system pressure and service conditions Capactiy - Rate of flow through the valve under stated conditions Fail - close - The condition wherein the valve port remains closed should the actuating power fail Fail - open - The condition wherein the valve port remains open should the actuating power fail Fail - last - The condition wherein the valve port remains in the last position should the actuating power fail |
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