Manual Ball Valve: A valve that is opened and closed by turning a handle attached to a ball inside the valve. The ball has a hole through the middle. Flow occurs when the hole is in line with both ends of the valve and stops when it is perpendicular to the ends of the valve. The handle is in line with the hole through the ball. Because the motion of the handle between the OFF and ON position is 90 degrees, the valve is classified as a quarter turn valve.
Things to Consider: Pipe sizes, Weight, Dimensions, Seal materials, Connection type, Body materials, Flow rates, Cv factor, Torque specifications, Operating temperatures, Warranty.
Manual Butterfly Valve: A valve used to regulate fluid flow. It is similar in operation to a ball valve. A flat circular plate is positioned in the center of a pipe. The plate is attached to a rod that connects to an actuator outside the valve. The actuator turns the plate either parallel or perpendicular to the flow. Unlike a ball valve, the plate is always present within the flow causing a pressure drop.
Things to Consider: Valve size, Seat material, Dry or wet service, Torque requirements, Size, Body style, Actuator style, Body material, Disc material, Warranty.
Manual Check Valve: A valve that allows liquid or gas to flow through it in only one direction. Check valves have only two ports: one for input and one for output. Check valves work automatically and are not controlled by a person or any external control.
Things to Consider: Media type, Body construction, Pressure rating, Temperature rating, NPT size, Pressure drop, Disc material, Seal material, Cracking pressure, Check suitability for applications involving repetitious vibration, Warranty.
Manual Diaphragm Valve: A device, also called a membrane valve, comprised of a valve body with two or more ports, a diaphragm, and a “saddle” or seat upon which the diaphragm closes the valve. Diaphragm valves are frequently used by the bio-pharmaceutical industry by using compliant materials that can withstand sanitizing and sterilizing methods. There are two types of diaphragm valves: the saddle type and the seat type. The saddle-type valve has two ports in line with each other on the opposite sides of the valve. The seat-type has the in and out ports located at 90 degrees from one another. The saddle type is common in process applications. The seat-type is commonly used as a tank bottom valve.
Things to Consider: Media type, Temperature service rating, Pressure service rating, Corrosion barrier/inner liner materials & construction, Body/cage construction, Exterior layer of valve body corrosion/impact/UV resistant, Bonnet/wheel handle, compressor/flange construction, External hardware material, Diaphragm material, Testing & quality assurance procedures, Size, Weight, Warranty.
Manual Gate Valve: A valve that is opened by lifting a gate out of the path of the fluid. The sealing surfaces between the gate and the seats are flat. The gate faces can form a wedge or they can be parallel. Gate valves are designed to be fully opened or closed. When fully open, a gate valve presents no obstruction in the flow path, resulting in very low friction loss.
Things to Consider: Size, End connections, Trims, Body material, Construction & materials for gates, Working pressure, Temperature range, Testing (for example 100% hydrostatic boy and seat test as per AP1 6A), Warranty.
Manual Valves. Devices that regulate the flow of gases or liquids by opening, closing, or partially obstructing passageways. Valves are used in a variety of applications including industrial, military, commercial, residential, and transportation. The valves most obvious in everyday life are plumbing valves such as: water taps, gas control valves on appliances, and safety devices fitted to hot water systems. Most manual valves are operated by a hand wheel or a lever, although some are self operating, controlled by internal mechanisms driven by changes in pressure, temperature, or flow.
Things to Consider: Media, Function, Ease of opening and closing, Ease of identifying position from a distance, Approvals, Pressure rating at ambient temperature, Body material, Seat material, Stem material, Packing material, Replacement handle availability, NPT size, Warranty.
Manual Globe Valve: A valve used for regulating flow in a pipeline. Globe Valves are named for their spherical body shape. Two body halves are separated by an internal baffle that has an opening that forms a seat onto which a movable plug can be screwed in or out to open or close the valve. The plug is connected to a stem which is operated by screw action turned by a handwheel. Some modern globe valves do not have a recognizable spherical shape. The term globe valve, however, is still used for valves that have such an internal mechanism. These valves are used for applications requiring throttling and frequent operation.
Things to Consider: Construction & materials, Screwed bonnet, Non-rising stem, Solid wedge disc, Pressure ratings for various media, Replacement handle availability, NPT size, Warranty.
Manual Plug Valve: Plug valves have cylindrical or conically-tapered plugs which are rotated inside the valve body to control fluid flow. These plugs have one or more hollow passageways going sideways through the plug, allowing fluid to flow through the plug when the valve is open. With conically-tapered plugs, the stem is attached to the large end of the plug. The simplest and most common general type of plug valve is a 2-port valve, which has two positions, open and shut, and is classified as a quarter-turn valve. This type of valve is often used as a shut-off valve in household natural gas lines. Some plug valves have more than two ports. In a 3-way plug valve, flow from one port could be directed to either the second or third port.
Things to Consider: Plug recedes into body, Size of cylinder, Vessel pressure, Availability of side openings, Packing construction & materials, Valve material, Overall pressure rating, Tapered metal to metal plug and seat – no lip seals to wear or replace, Warranty.
Pressure Regulator Valve: A valve that automatically cuts off the flow of a liquid or gas at a certain pre-set pressure. These valves allow the pressure from high-pressure sources to be reduced to controlled levels for specific applications.
Things to Consider: Dimensions, Weight, Mounting method, Standard port, Pressure cartridge ratings, Maximum flow, Maximum working pressure, Construction & material, Warranty.
Manual Relief Valve: A valve used to limit the pressure in a vessel to a certain maximum level. Pressure is relieved by allowing pressurized media to escape out of the system. The valve is designed or is set to open at a predetermined pressure. When the pressure setting is exceeded, the relief valve becomes the “path of least resistance.” The valve is forced open and a portion of the media is diverted through the auxiliary route. As the media is released, the pressure inside the vessel drops. Once it reaches the valve’s re-seating pressure, the valve closes.
Things to Consider: Nominal disc size, Burst pressure and coincident burst temperature, Burst tolerance, System design pressure, Design temperature, Allowable accumulation (%), Fluid/State, Operating temperature minimum and maximum, Operating pressure minimum and maximum, Relief temperature, Molecular weight (gas or vapor), Ratio of specific heats, Specific gravity at relieving conditions (liquid), Viscosity at relieving conditions, Compressibility factor, Superimposed back pressure minimum and maximum, Frequency of pressure cycling, Min and max cyclic pressure, Required capacity, Relief valve (Yes/No), Combined capacity factor, Maximum combined capacity, Reaction force, Discharge line orientation critical, Orientation pipe sketch, ASME certification required, Replacement frequency, Materials of construction: Pressure disc, Support ring (inlet side), Support ring (outlet side), Soft gasket, Vacuum support, Sealing disc, Sealing disc cover, Liner (inlet side), Liner (outlet side), Coating (inlet side), Coating (outlet side), Teeth ring, Warranty.