Plug valve manufacturer

What is a plug valve?

The plug valve is a fitting with a conical or cylindrical shut-off body (also throttle body), the so-called plug.

Where are plug valves used?

Due to their design, plug valves are free of dead space in both the open and closed position - i.e. no residues can form. This favours the use with media containing solids and crystals. The service life of the plug valve is much longer than that of ball valves, for example. Severe damage to the seat and plug when the valve is actuated is ruled out because no solid particles can get stuck between the plug and the sealing seat (the sleeve).

The proven has a future - plug valves from KÄHLER

KÄHLER plug valves - also called cylinder valves - are robust and compact, designed for undemanding behaviour in use with an almost unlimited service life.

The installation position can be chosen at will. The space requirement is extremely low, even for large nominal sizes. The design is uncomplicated and straightforward.

Cylinder / plug

The shut-off element in the plug valve is the cylinder with an exact fit for the valve body. This precise guidance and the constant film of sealant between the housing and the cylinder prevent foreign bodies from penetrating between the sealing surfaces and rule out damage and possible leaks as a result.

Our design has the advantage that the cylinder can be moved effortlessly and does not get stuck. Perfect switching is guaranteed at all times.

Flow area of plug valves

The port in the cylinder is normally rectangular and either fully corresponding to the pipe cross-section or reduced. The reduced port is generally one nominal size smaller than the connection cross-section. The rectangular port was chosen to achieve smaller external dimensions and a low-cost design.

For special applications, KÄHLER cylinder valves can also be supplied with a full round port, which corresponds exactly to the pipeline in shape and size and can be piggable.

Sealing with a system

An important distinguishing feature from other types of valves is the re-sealing system. This system is an important element within the construction of the valve and fulfils its function of perfect sealing to the inside (in all flow directions) and to the outside with amazing reliability and durability.

The KÄHLER plug valve can be resealed from the outside at any time and without any risk during operation. Via the sealant screw(s), a sealant adapted to the flow medium is pressed through channels between the housing and the cylinder. The re-sealing system has other excellent properties that are not achieved by other types of seals (metallic or soft):

• No corrosion and no wear on the sealing surfaces.
• No metal-to-metal contact and no sticking.
• Insensitive to foreign particles.
• No repair to the sealing surfaces and therefore no dismantling of the fitting.
• Flexible and easily rotatable seat in the housing.
• Temperature resistant up to + 250° C.
• Faultless operation even after very long downtimes.
• Reliable sealing for decades without operating faults.

Profile ring / stem sealing of plug valves

The KÄHLER cylinder valve is glandless. Sealing to the outside is achieved by the sealant and additionally by a maintenance-free profile ring made of PTFE with a stainless steel spring on the cylinder stem or by an O-ring. These rings can withstand tens of thousands of switching operations, as the switching travel of the tap is short and vertical abrasion due to sliding or rolling does not occur due to the design. The stem seal does not function as a pressure-bearing element and is not a wearing part.

Operation of plug valves

The open or closed position of the KÄHLER plug valve is achieved by turning the cylinder 90° to the stop. The actuation is normally done up to DN 150 with a star key, larger nominal diameters with worm gear or additionally with electric, pneumatic or hydraulic actuator. But the smaller DN can also be equipped with automatic actuation. All cocks have an always clearly visible indication of the respective cylinder position.

Plug valves with rectangular port

The port in the cylinder of the standard models is rectangular. The smooth transition from the round inlet and outlet of the valve body (analogous to the pipe connection) to the rectangular cylinder port is designed so favourably in terms of flow technology that only extremely low pressure losses occur and excellent flow values are achieved. KÄHLER cylinder valves with rectangular port are available in two versions:

1. Port fully corresponding to the pipe cross-section:
   Vertical extensions of the rectangular cylinder port compensate for the lateral constrictions to such an extent that the full pipe cross-section is achieved.
2. Reduced port:
   The reduced port in the cylinder is for the most part smaller by one nominal size than the cross-section on the inlet and outlet side of the tap. The pressure loss is somewhat higher, but the price is lower.

Plug valves with round port

The port in the cylinder of these special models has a full, round shape and is also exactly the same size and shape as the pipe cross-section. This design is recommended when pigging is necessary, for highly erosive flow media or those that tend to clog in cross-sectional constrictions.