High-Temperature Butterfly Valves for pipes

Shut-off valves in detail: overview, designs and applications

Below you will find an overview of these common shut-off valves and their applications.

Butterfly valve:

Butterfly valves can stop the flow of the pipeline through their rotating disc. They are actuated by a hand lever or, for larger nominal sizes, via a gearbox. This moves the center-mounted flap disc to open and close at 90°. For automating the butterfly valves, electric and pneumatic actuators are suitable. Common 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 does not require an additional gasket for installation. Additionally, metallic-sealing butterfly valves are also possible. In the lug type of butterfly valves, these are equipped with internal thread bores that match the flange. This butterfly valve is suitable for installation at the end of the pipeline without the need to mount a second flange.

This type of installation significantly simplifies the drainage of the pipelines. Due to the short total length of a butterfly valve, the required space in pipelines is very small. It is also worth noting the low weight of the butterfly valve. This is particularly advantageous where there are no, or only a few, options to support the pipelines. For sealing materials, EPDM, NBR or VITON are used in soft-sealing butterfly valves. Butterfly valves made of PVC-U also belong to shut-off valves. However, they cannot compete with cast iron butterfly valves in resistance and versatility of applications. An example of a wafer type butterfly valve is the ACI butterfly valve Series 22. For lug type butterfly valves, it is the ACI butterfly valve Series 23.

Gate valve:

Gate valves are not shut-off valves that regulate the flow; they stop the complete flow. With secure shut-off, it is possible to carry out maintenance, repairs, or drainage behind the gate valve without any problems. Due to their wedge design, gate valves cannot limit the flow. There are only open and closed positions with these shut-off valves. Therefore, gate valves are referred to as full passage. The shut-off wedge in a gate valve can be distinguished between wedge-flat, wedge-oval and wedge-round. Gate valves can be manually actuated, for example, by a handwheel, or via pneumatic or electric drives. The application areas of gate valves typically include media such as water, wastewater, gas, or even bulk materials. The previously specified precision and execution of gate valves significantly determines the quality and service life. Flange connections according to DIN EN, welding ends according to DIN or ANSI designs are available as connections.

Nominal sizes are possible from DN 40 to DN 2000 depending on type and design. Additionally, socket gate valves with an internal thread for installation in, for example, an industrial heating system are possible. For the correct selection of valves, the medium, working temperatures, and nominal pressure (PN) must be considered. The application determines whether it is advantageous to choose a soft-sealing or metallic-sealing gate valve. The materials for the housings primarily include 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 principle, the installation conditions for gate valves should never be neglected. For example, with underground installation, the installation position, as well as the type and length of the spindle, must be considered. The type of spindle can vary between outside and inside spindles.

Shut-off valve:

Shut-off valves allow for controlled shut-off and closing of the pipeline, unlike ball valves, ball valves, gate valves, and butterfly valves. Due to the design of these valves, continuous regulation of the flow rate is possible as long as a throttle cone has been installed. Due to the different cone variants of shut-off valves, depending on the selection of materials, they are suitable for high differential pressures, pressure shocks, and high temperatures. The materials for the housings used in shut-off valves include grey cast iron GG 25 / EN GJL 250, ductile cast iron spheroidal cast iron GGG 40 / EN GJS-400-15, steel casting GP240GH / GS-C 25 / 1.0619, or stainless steel casting 1.4408. These valves are actuated manually via a handwheel or automatically via an electric or pneumatic swivel drive. In sealing the valve spindle, there is a distinction between bellows and packing.

Bellows shut-off valves are maintenance-free compared to other valves and allow for long service times. The bellows sealing provides the shut-off valve with more performance and increased safety.

Packing shut-off valves, however, must undergo maintenance at predefined intervals. The packing must be regularly adjusted or replaced for a consistent seal.

Common media for shut-off valves include water, gas, condensate, and thermal oils. The connection possibilities of shut-off valves are very variable. These valves can be designed with flange connections according to DIN EN 1092-1 from nominal size DN 15 to DN 300. Additionally, flange connections according to ANSI Class 150 to 1500 are also possible. The connection of shut-off valves can also be made using threaded connections from 1/2 inch to 2 inches according to ANSI Class 300. Depending on the chosen connection variant, a shut-off valve can be supplied in pressure levels from PN 16 up to PN 500.

Optional designs, such as limit switches for pneumatic and electric swivel drives, are also part of our repertoire.

ACI Industriearmaturen is happy to assist you in selecting a shut-off valve suitable for your process. Whether it is a butterfly valve, gate valve, shut-off valve, through-type or corner-type, welding ends, flanges, thread connections, and these in DIN or ANSI. We advise you individually and tailored so that we can deliver exactly the valve that fits your application. Contact us for a suitable offer or if you need more information about shut-off valves.

Contact us for a suitable offer or if you need more information about shut-off valves.