Cut-Off; Stellited Seat And Cone; Mounting Position - Mankenberg DM Originalbetriebsanleitung

Original operating manual
Pilot-controlled pressure regulators DM
With steam as medium, the pressure reducer should be preceded by a water trap, which is also called steam
dryer, to protect it from cavitation (see below chapter "Steam Operation").

14.10 Cut-off

For the purpose of installation, servicing and isolation of the valve, shut-off valves should be installed upstream
and downstream of the pressure reducer. When closing the shut-off valves the upstream valve must always be
closed first. A bypass line may be necessary to maintain emergency operation.

14.11 Stellited seat and cone

In the case of abrasive media or liquids with pressure drops (inlet pressure minus outlet pressure) of more than
25 bar the valve cone must be stellited; for pressure drops above 150 bar the seat must be stellited as well.

14.12 Mounting position

The installation site to allow perfect functioning of a fitting should be a section of pipe without any flow
disruptions, without any angles and without any restrictors or shut-off devices close to the fitting, either
upstream or downstream (optimum distance = 10 x DN).
For gases a pressure reducing valve can normally be fitted in horizontal pipelines with the spring cap at the
bottom or at the top. Installation in vertical pipe runs is possible but can result in increased wear and loss of
control accuracy owing to increased friction.
In the case of liquids a pressure reducer should be installed with the spring cover at the bottom. Thus gas traps
upstream of the valve are avoided which would cause the valve to oscillate.
Recommended installation for liquids and gasses
1 Strainer or filter
2 Shutoff valves
3 Pressure reducer
4 Safety valves
5 Pressure gauge
6 Sense line
7 Leakage line
8 Bypass for maintenance
Sense line connection 10 - 20 x DN behind the
valve
For steam a pressure reducer should likewise be installed with its spring cover at the bottom to protect the
diaphragm against overheating by means of a layer of condensate.
DM-4.X.222 Issue 18.07.2022
22
www.mankenberg.com