TDL Pump protection valve for centrifugal pumps- Compact pump protection - high bypass flow
The outlet main flow controls the non-return valve and positions it in proportion to the flow. The stem of the non-return valve transmits the motion via a lever to the bypass. The bypass system regulates the bypass flow in a modulating way and reduces the pressure to the bypass outlet pressure level without cavitation.
When the non-return valve is completely closed, the entire minimum flow is routed through the bypass. The bypass is fully closed when the non- return valve is in its upper position, thereby allowing full pump flow to the system.
Flow sensitive modulating bypass control
The non-return valve moves upwards with increasing main flow and downwards with decreasing flow. The non-return valve transmits this movement to the control lever.
The movement of the control lever is transferred to the control bushing. This opens the control holes in the control head by a greater or lesser degree. The opening characteristic is linear. Applicable for differential pressures up to 40 bar. Standard with non-return function.
Manual bypass options for TDL valves
Depending on the plant design or additional requirements, various options can be selected for the start-up / warm-up side (A) and for the bypass side (B).
One frequently used option is to feed low pressure flow to the process / boiler via the manual start-up. Either for the warm-up process or for heating the adjacent pumps/systems.
Depending on the operating conditions of the system (dirt, certain load cases, etc.), special internal parts can be selected for the bypass. The valve is then supplied with the integrated optional bypass set. In this case the original internal parts for the bypass are supplied and installed after commissioning.
- Automatically modulating bypass function
- Carbon steel or stainless steel
- Special materials possible (e.g. Super Duplex)
- Internal operation (no external energy source required)
- Easy to install
- Low maintenance
- Suitable for all liquids
Nominal diameter: DN 25 – 500 / NPS 1 – 20
Pressure class: PN 10 – 160 / Class 150 – 900
Temperature (max.): Up to 230 °C / 446 °F (other temperatures on request)
Housing material: 1.0460 / A105
1.0571 / LF2
1.4404 / F316L
1.4462 / F51
1.4501 / F55
Housing type: Forged or cast
Media: Liquids of all kinds (water, oils, chemicals and others)
Flanges: EN 1092-1, ASME B16.5, ISO 7005, JIS, JPI, (welding ends on request)
Designs: Vertical installation, horizontal installation, manual start-up, enlarged nominal width of the bypass, degassing connection
Number of stages (max.): 1
Number of controlled stages (max.): 1
Operating range (max.) : Delta p up to max. 40 bar
Other: Bypass differential pressure up to 40 bar
The TDL valve should be installed as close as possible to the discharge port of the centrifugal pump, preferably directly on the pump discharge port of the pump.
To avoid frequency interference due to pressure oscillations in the medium, the distance between the pump outlet and the valve inlet should not exceed 3 m. Take care to ensure a straight inlet section. Exceptions have to be confirmed to SCHROEDAHL.
Vertical installation is preferred, but horizontal installation is also possible upon request. TDL valves operate at a low noise level and ensure a high reliability due to their sturdy design.
The recommended filter at the pump inlet should have a mesh size of 0.3 to 0.5mm. A smaller mesh size of 0.1mm is recommended for commissioning.
Schroedahl Customer Care
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