Flow Velocity - Mankenberg UV 5.1 ATEX H2 Betriebsanleitung

Supplement to the Operating Instructions for
Back pressure regulators UV 5.1 ATEX H2

16.5 Flow velocity

Depending on pressure drop and permitted maximum noise level, we recommend the following flow velocities:
Liquids 1
Saturated steam 10
Superheated 15
steam
Gases below 2 bar 2
Gases above 2 bar 5
16.6 Sense line (control line)
You should install a sense line if the selected back pressure regulator is designed for sense line operation. The
sense line should be connected at a distance of not less than 10 times nominal diameter upstream of the valve.
No isolating valves should be installed in the sense line to avoid an excessive pressure differential between
valve body and diaphragm. To attenuate any oscillations occurring in the pipeline system, the sense line may be
fitted with a restrictor which must never be fully closed during operation.
In the case of steam and liquids the sense line must be installed so as to fall towards the valve. Under special
operating conditions, for example intermittent operation with dry steam, an compensation vessel must be
installed. The sense line must be rigid as elastic hoses can induce oscillations.
16.7 Protecting your system
To protect your system you should install a safety valve upstream of the back pressure regulator to prevent the
maximum permitted operating pressure (normally 1.5 x maximum set pressure) being exceeded. The safety
valve operating pressure should be set approximately 40 % above the maximum set pressure of the back
pressure regulator to avoid blow-off during slight pressure fluctuations.
For example: if the setting range of the back pressure regulator is 2 - 5 bar the safety valve operating pressure
must be 1.4 x 5 bar = 7 bar.
16.8 Protecting the back pressure regulator
To protect the back pressure regulator against damage from solid particles carried in the pipeline, a strainer or
filter should be fitted and serviced at regular intervals.
16.9 Valve seat leakage
These valves are no shut-off elements ensuring a tight closing of the valve. In accordance with DIN EN 60534-4
and/or ANSI FCI 70-2 they may feature a leakage rate in closed position in compliance with the leakage classes
II – V:
Leakage class II (metal sealing double seat cone) = 0,5% K
Leakage class III (metal sealing cone) = 0,1 % K
Leakage class IV (PTFE seal cone)= 0,01 % K
Leakage class V (soft seal cone) = 1,8 x 10
*D=seat diameter
Any low leakage requirement must be expressly specified when ordering. Valve leakage can be considerably
reduced by special measures such as lapping the valve seat, using special cone seals and increasing the
control (diaphragm) surfaces.
16.10 Cut-off
For the purpose of installation, servicing and isolation of the valve, shut-off valves should be installed upstream
and downstream of the back pressure regulator. When closing the shut-off valves the upstream valve must
always be closed first. A bypass line may be necessary to maintain emergency operation.
UV 5.1 ATEX H2-4.X.22.5 Issue 21.12.2022
- 5 m/s
- 40 m/s
- 60 m/s
- 10 m/s
- 40 m/s
value
vs
value
vs
-5
x Δp x D* [l/h]
29
value
vs
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