WIKA

Valves and protective devices

Valves and protective devices for increased safety and service life

Shut-off valves, valve manifolds or monoflanges, can be used to securely separate pressure measuring instruments from the process during commissioning, maintenance or calibration. Protective devices, such as siphons, overpressure protectors and snubbers, increase the service life and extend the application spectrum of pressure measuring instruments. Alongside the extensive selection of instrumentation valves and accessories, WIKA also offers qualified assembly of different individual components into a complete measuring unit.

What is a valve?

A valve is used to separate the process from measuring instruments such as pressure gauges, switches or transmitters. Valves thus act as a shut-off and are also called shut-off devices. By closing the valve the measuring instrument can be safely dismounted for services like recalibration or replacement. WIKA's broad and diverse range of valves and instrument hook-ups (entire measuring assembly) are used in a variety of ways. The range of use extends from gaseous, liquid and aggressive media to highly viscous or crystallising media. The valves are suitable for demanding applications in diverse industries.

When is a block-and-bleed valve used?

The block-and-bleed valve is used for simple isolation (block) and venting (bleed) of pressure measuring instruments such as pressure gauges, switches or transmitters. They are used as an alternative to systems with several valves and thus also offer a low weight and less chance of leakage for a more leak-tight system. The overload protection they feature increases the service life of the pressure measuring instrument.

When is a valve manifold recommended for differential pressure measuring instruments?

Valve manifolds are recommended for the connection of pressure transmitters, differential pressure transmitters, pressure gauges and differential pressure gauges to the technological process. One differentiates between 3-valve and 5-valve manifolds:
3-valve manifolds are composed of two shut-off valves and one pressure compensating valve. The shut-off valves have the task of isolating the process from the differential pressure measuring instrument, while the pressure compensating valve makes it possible to balance between the plus and minus sides in order to avoid one-sided overpressure.
5-valve manifolds expand on 3-valve manifolds with two further vent valves, which enable targeted venting of the measuring arrangement.

When is it suitable to use ball valves?

Ball valves have a diverse field of application. It is used from the simple distribution of compressed air through to demanding applications in the oil and gas industry, and is especially suitable for applications with natural gas and aggressive media. Due to its very easy cleaning, a ball valve is particularly recommended for liquid and gaseous media.

How does a check valve work?

Check valves ensure, with the assistance of a double-sealing system, that the liquid in the pipe only flows in one direction. The sealing element (piston) opens and closes as soon as a liquid or gas flows or the direction of flow changes. With any back pressure, the soft O-ring and then the sealing face of the metal cone prevent the reverse flow of the medium. The model CV check valves are suited specifically for applications with natural gas and aggressive fluids, as well as for water and hydraulic oil.

What is a monoflange?

The monoflange, through the one-piece design, withstands high overpressures and results in a robust and also compact mounting of the measuring instrument directly at the process flange. The use of metal and graphite seals allows working at high temperatures.

How does a monoflange work?

The functionality of a monoflange corresponds to that of a traditional valve. Here, the circular valve clamps are connected by drilling holes through the monoflange bodies. This creates two shut-off valves, or shut-off bodies, which enable better separation from the process. The second valve guarantees safe separation from the medium, should this not be done properly by the first valve. Further information on this can be found in our WIKA blog post “How does a monoflange work?”.

What is a monoblock valve?

A monoblock is a compact, reducing station which is used for the high-pressure range. The entire high-pressure part of a natural gas reduction station is provided by a filter with optional separating section and a heat exchanger with stainless steel pipes. A distinction is made between monoblocks with threaded connection, which are used for the limited space conditions of control panels and valve batteries and monoblocks with flange connections, which are used in applications with natural gas and aggressive media. In addition, there are monoblocks for sampling and injection processes, which have a probe for sampling and are also used for injection processes.

What purpose does a needle valve serve?

Needle valves are used when a liquid or gaseous medium must be precisely controlled or the flow rate must be precisely metered. They are also used for the shut-off and venting of pressure measuring instruments. In particular, the model HPNV high-pressure needle valve is used for installations with constricted space for control panels or for test benches. Seizing and scraping within the valve is prevented by the non-rotating valve spindle, which increases the service life of the unit in the case of frequent opening and closing.

What are needle valves made of?

Needle valves are made of robust, durable materials such as stainless steel, bronze, brass or metal alloys.

Easily select the product most suitable for you directly from our product portfolio in our WIKA online shop.

WIKA is happy to support you in the selection of the correct components for your application. Alongside the extensive selection of instrumentation valves and accessories, WIKA also offers qualified assembly of different individual components into a complete measuring arrangement (“instrument hook-up”). The WIKA valves and protective devices can also be combined with diaphragm seal systems. Most of our accessories portfolio can be delivered directly from stock.

FAQ
FAQ

What does „Pt100“ mean?

Pt stands for Platinum with a nominal resistance of 100 Ohm at 0 °C (EN 60751).