Shut-off valves

Shut-off valves are industrial valves that allow controlled opening or closing of the pipeline. Different versions can be used for this type of valve, depending on the nominal pipe diameter and the intended function. These valves can be classified as butterfly valves, gate valves or globe valves.

The following section provides you with an overview of these common shut-off valves and their possible applications.

Butterfly valve:

Butterfly valves are able to shut off the flow of the pipeline by their rotating disc. Butterfly valves are operated, for example, by a hand lever or, in the case of large nominal diameters, by a gear. These move the centrally mounted valve disc open and closed. Electric and pneumatic actuators are suitable for automating the butterfly valves. Typical media are, for example, water, gas or steam. Butterfly valves are available in wafer type and lug type. Wafer type butterfly valves can be mounted between two flanges. A soft-sealing butterfly valve means that no additional gasket is required for installation. Metal-sealing butterfly valves are also possible. The butterfly valves with threaded eyes are equipped with holes to match the flange. These butterfly valves are suitable for installation at the end of the pipeline without having to install a second flange. With this type of installation, the emptying of the pipelines is considerably simplified. Due to the short overall length of a butterfly valve, the space required in pipelines is very small. The low weight of the butterfly valve also deserves special mention. Especially where there are no or only few possibilities to intercept the pipelines, this is of advantage. EPDM, NBR or VITON are mostly used as sealing materials for soft-sealing butterfly valves. Butterfly valves made of PVC-U also belong to the group of shut-off valves. However, they cannot compete with cast iron butterfly valves in terms of resistance and versatility. The ACI butterfly valve series 22 is an example for butterfly valves with intermediate flanges. ACI butterfly valve series 23 is an example for butterfly valves with threaded eyes.

Gate valve:

Gate valves are not shut-off valves that regulate the flow, they stop the complete flow. Due to the safe shut-off function it is possible to carry out maintenance, repairs or draining behind the gate valve without any problems. Due to their wedge design, gate valves cannot limit the flow. These shut-off valves have only one open and one closed position. This is why gate valves are referred to as full passage. The wedge in a gate valve is divided into flat wedge, oval wedge and round wedge. Gate valves are operated manually, for example by a handwheel, pneumatic or electric actuators. The areas of application for gate valves usually include the media water, sewage, gas or even bulk material. The previously specified precision and design of the gate valves have a significant influence on quality and service life. Flange connections according to DIN EN, welding ends according to DIN or ANSI are available as connections. The nominal diameters are possible from DN 40 to DN 2000 depending on type and design. In addition, threaded gate valves with an internal thread are also available for installation in, for example, an industrial heating system. For the correct selection of valves, the medium, the operating temperatures and the nominal pressure (PN) must be taken into account. The application determines whether it is an advantage to select a soft-sealing or metal-sealing gate valve. The materials used for the bodies are mainly grey cast iron GG 25 / EN GJL 250, ductile cast iron spheroidal cast iron GGG 40 / EN GJS-400-15 or high-quality stainless steel. In general, the installation conditions for the gate valve are not to be underestimated. For example, the installation position and the type and length of the spindle must be taken into account when installing the gate valve in the ground. The type of spindle can vary between external and internal.

Globe valve:

In contrast to ball valves, gate valves and butterfly valves, globe valves allow a controlled shut-off and closing of the pipeline. Due to the design of these valves, continuous control of the flow rate is possible if a regulating disc has been installed. Depending on the materials selected, the various disc variants allow the globe valves to be used for high differential pressures, pressure surges and high temperatures. The materials used for the housings of globe valves are cast iron GG 25 / EN GJL 250, ductile cast iron spheroidal graphite cast iron GGG 40 / EN GJS-400-15, cast steel GP240GH / GS-C 25 / 1.0619 or stainless steel 1.4408. These valves are operated manually via a handwheel or automatically via an electric or pneumatic rotary actuator. A difference is made between bellows and stuffing boxes in the sealing of the valve stem. Bellows seal Globe valves, unlike other valves, are maintenance-free and allow long service lives. The bellows seal provides the globe valve with more performance and increased safety. On the other hand, stuffing boxes globe valves must be serviced at predefined intervals. The stuffing box packing must be regularly readjusted or replaced to maintain a constant seal. Common media for globe valves include water, gas, condensate and thermal oils. The connection possibilities of the globe valves are very variable. These valves can be supplied with flange connections in accordance with DIN EN 1092-1 from nominal sizes DN 15 to DN 300. Flange connections according to ANSI Class 150 to 1500 are also possible. The globe valves can also be connected by means of threaded connections from 1/2 inch to 2 inch according to ANSI Class 300. Depending on the selected connection variant, a globe valve can be supplied in pressure stages from PN 16 up to PN 500.

Optional designs such as limit switches for pneumatic and electric rotary actuators are also part of our repertoire.

ACI Industriearmatruen will be happy to help you choose the right shut-off valve for your process. No matter if butterfly valve, gate valve, globe valve, straight or angle form, welding ends, flanges, threaded connections and those in DIN or ANSI. We offer you individual and tailor-made advice to ensure that you receive exactly the right fitting for your application. Contact us for a suitable quotation or if you require further information on shut-off valves.

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