TDM Pump protection valve for centrifugal pumps
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 lever is transmitted via a piston to the multi-stage vortex plug. The minimum flow is then bypassed in a modulating way over several pressure reduction stages.
The TDM can be used for differential pressures from 20 bar up to 230 bar. The standard TDM design has a built-in bypass non-return function (~2 bar dp level required).
Manual bypass options for TDM 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).
Option A:
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.
Option B:
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.
General information
Product features
- Automatically modulating bypass function
- Forged housing material, 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
Technical data
Nominal diameter: DN 25 – 300 / NPS 1 – 12
Pressure class: PN 63 – 400 / Class 150 – 2500
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
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.): 5
Number of controlled stages (max.): 5
Operating range (max.): Delta p up to max. 230 bar
Other: Bypass differential pressure 20 – 230 bar
Installation information
The TDM 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 3m.
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. TDM 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
Data
Design Standard
Unit
Temp
Pressure Rating
Nominal size
Housing
Stages
Other data
Images
Files
Contact
Schroedahl Customer Care
SCHROEDAHL GmbH
- A subsidiary of Circor International -
Alte Schönenbacher Str. 4
51580 Reichshof-Mittelagger
Germany
Phone +49 2265 9927-0
Fax +49 2265 9927-947
schroedahl@circor.com