In this film we would like to present to you two Schroedahl high pressure valves; the TDM and the MRK.
Properties such as functionality, fields of operation, valve specifications and the delimitations to each other, clearly indicate the valve that best meets your needs
Hi John,
again we want your voice on our Schroedahl movies.
You already know how to pronounciate the firm name.
Have a good time with automatic recirculation valves ;-).
Stephan
Our bestseller; the TDM!
50,000 units sold to satisfied customers make the TDM the perfect valve for safeguarding production in both the low pressure and absolute high pressure ranges.
Its robust design can withstand a differential pressure from 20 to 230 bar.
This makes the TDM ideally suited for applications in power stations, oil drilling rigs and for many process industries
Externally, the TDM is very similar to our TDL.
The check valve and the bypass once again create the "valve intelligence".
But the conical shape of the main check valve used in the TDM combined with the multi-stage vortex plug in the bypass enables the TDM to handle a pressure difference five times greater than the TDL.
How does the TDM work?
The delivery flow brings the non-return check valve or main check valve into the calculated vertical position.
The non-return check valve transmits this movement to the red control lever of the Automatic Recirculation Valve bypass.
This moves the orange multi-stage vortex plug in the vortex bushing and opens or closes the bypass.
The design of the vortex plug / vortex bushing reduces the modulating pressure in the bypass system.
The following animation shows how this works using the integrated characteristic curve.
Our animation assumes a minimum flow of 30%.
The valve switch point is marked in red on the characteristic curve.
When it is reached, the valve closes the bypass and no medium flows into the safety flow chamber.
A downstream feed water control valve regulates the flow rate depending on the partial load or full load requirement.
The switch point is defined according to your requirements, and 50 years of Schroedahl competence are used to create a robust valve design.
The TDM is produced from high-quality carbon steel, stainless steel, low-temperature steel and duplex steel
The result is a valve that is flexible and yet suitable for robust applications.
Media at temperatures of between - 45 degrees and + 230 degrees Celsius can be processed without problem.
Pressure reduction in the bypass can consist of up to 5 stages. This makes possible a differential pressure range from 20 to 230 bar.
The nominal width range extends from
DN25 to DN 500
The pressure stage for the TDM is designed from PN 63 to PN 400.
TDM valves are mainly used in feed water applications in power plants. However, its robustness makes many other fields of application conceivable.
MRK is the valve for the absolute high pressure and partial load range, and is particularly suitable for speed-controlled pumps.
The MRK is a further development of our successful TDM range of high pressure valves. It combines a cost-effective approach and a highly refined technology.
Pressures up to 500 bar can be reduced by the unique two-part bypass design with 7 to 9 regulated stages. This is achieved via the main non-return check valve with minimum energy loss.
If no process volumes are extracted the main check valve is in the seat and no further medium flow to the receiver occurs.
The Automatic Recirculation Valve is opened to the maximum and this supplies the volume required for every speed.
The pump can keep running even if the process is not extracting any media, the required minimum volume being discharged via the bypass system on the MRK.
The minimum process media conveyance remains active, which means that the unnecessary and fault causing stopping of the pump does not occur.
The MRK functions as a modulating unit right up to full load.
In this context SCHROEDAHL interprets the term modulation to mean the minimum volume is automatically reduced with increasing process volumes.
The switch point of the MRK is very low, ensuring high efficiency throughout the entire process
The position of the main check valve varies according to the pump delivery rate.
The MRK, like the TDM, is produced from high-quality carbon steel, stainless steel, low-temperature steel and duplex steel
The result is a valve that is flexible and yet suitable for robust applications.
This enables faultless processing at temperature ranges of
between - 45 degrees and + 230 degrees.
Pressure reduction in the double bypass system can consist of up to 9 stages. This makes possible a differential pressure range from 20 to 500 bar.
The nominal width range extends from DN 80 to DN 350.
With the MRK the pressure stage is even designed for up to PN 640.