Double-seat Valves
VARIVENT® Mixproof shut-off valves for CIP & gas blocks
VARIVENT® mixproof valves type C and K are used for mixproof separation of incompatible products at pipeline junctions within CIP systems or gas blocks.
Function
When the valve is closed (non-actuated position), there are always two seals between the separated pipelines. If one seal is defective, the resulting leakage will be directed through the leakage outlet into the periphery, without mixing with the product in the second pipeline.
Application Examples
VARIVENT® double-seal valves type C and double-seat valves type K are predominantly used in areas where hygienic is not critical, e.g. CIP systems and gas blocks (brewery)
The Valve Types
Valve type K represents a typical double-seat valve with two independent valve discs in which these two seals are located.
Valve type C, on the other hand, is a double-seal valve in which these two seals are together with the leakage chamber in between them in a valve disc.
In both versions, two seals prevent any mixture between a product line and a line carrying a cleaning media.
| Double-seal valves, type C valves | Double-seat valves, type K |
| DN 25 – DN 150 | DN 25 – DN 150 |
| OD 1" – OD 6" | OD 1" – OD 6" |
| IPS 2" – IPS 6" |
| Application | Sealing | Feature | Type |
| Product Range | Axial Sealing (Switching Leakages) | Modular System | Double-seat Valve, Type D |
| Product Range | Axial Sealing (Switching Leakages) | With Water Hammer Safety | Double-seat Valve with Balancer, Type B |
| Product Range | Radial Sealing | With Water Hammer Safety | Radial Sealing Double-seat Valve, Type R |
| Product Range | Axial Sealing (Switching Leakages) | Viscous Products or Products with large Particles | Double-seat Long-stroke Valve, Type D_/V |
| Product Range, piggable | Radial Sealing | Pigging Pipe
Top | Piggable Double-seat Valve Upside Down, Type L_H |
| Product Range, piggable | Radial Sealing | Pigging Pipe Bottom | Piggable Double-seat Valve Upright, Type L_S |
| Gas Blocks &
CIP Systems | Modular System | Double-seal Valve, Type C | |
| Gas Blocks &
CIP Systems | Modular System | Double-seat Valve, Type K |
Cleaning the Leakage Chamber
Mixproof Valves VARIVENT® C
Double-seal valve type C
In the standard version, two flushing valves are connected to the leakage chamber between the two valve disc seals.
One flushing valve is always used for the leakage outlet, while the second flushing valve is in contact with cleaning media through an olive screw fitting, in order to clean the leakage chamber.
In this case, it is necessary to have a supply valve connected in the periphery to supply the flushing valve with cleaning media at the required time.
Cleaning takes place while the main valve is closed, which means the seal surfaces of the valve disc seals that are in contact are not reached.
Cleaning the Leakage Chamber
Mixproof Valves VARIVENT® K
Double-seat valve type K
The double-seat valve type K does have neither an external spraying connection nor a lifting actuator. The leakage chamber is flushed by the fluid that emerges from the leakage chamber as a result of the switching leakage during the main stroke.
For this reason, the valve is not suitable for use in hygienic areas.
The advantages of the valve type K are its slightly increased safety against water hammers that could occur in the lower pipeline, as well as having a wider selection of available housing combinations.
Technical Data
Type C & KPlease refer to the catalog for more information.| Type C | Type K | |
| Material in contact with the product | 1.4404 / AISI 316 L | |
| Material not in contact with the product | 1.4301 / AISI 304 | |
| Seal material in contact with the product | EPDM, FKM, HNBR | |
| Ambient temperature | 0 to 45 °C | |
| Air supply pressure | 6 bar (87 psi) | |
| Product pressure | 5 bar (73 psi) | |
| Surface in contact with the product | Ra ≤ 0.8 μm | DN, OD Ra ≤ 0.8 µm
IPS Ra ≤ 1.2 µm |
| External housing surface | Matte blasted | |
| Control and feedback system | Connection 0 (without control top) | |
| Actuator type | Pneumatic actuator air / spring | |
| Connection fittings | Welding end | |
| Identification | Adhesive ID tag | |
| Valve seat version | Fixed vertical port | Clamped or welded seat ring |
| Certificates | EHEDG, CE | A3, CE |
Downloads
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VARIVENT® double-seat valves are used for mixproof shut-off of incompatible products at pipe junctions.
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