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2 installing valves with butt weld ends, 3 installing valves with balancing plugs, Operating and installation instructions stobu – ARI Armaturen STOBU PN63-160 EN User Manual

Page 9

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Operating and installation instructions

STOBU

®

PN63-160

Rev. 0040102002 0213

Page 2-9

5.2 Installing valves with butt weld ends

Please note that only qualified persons using appropriate equipment and working in
accordance with technical rules are allowed to install fittings by welding.
The responsibility for this lies with the system owner.
Refer to the data sheet for information about the shape of the butt weld ends.
The valves must be welded in closed position.

5.3 Installing valves with balancing plugs

Valves with pressure balancing plugs have to be installed with medium flowing over the
plug (pos. 3) as indicated by flow direction arrow on valve body.
Working principles:
When the valve is closed, anticlockwise rotation of the hand wheel lifts the pilot plug
(pos. 3.1) off the larger balancing plug (pos. 3). This allows the medium to pass through the
plug and equalizes the pressure of the medium under the plug (pos. 3). After the pressures
have been equalized within the values stated in the table below, the valve can be opened
by turning the valve further.

- Pressure balancing plugs are fully effective only in closed line section.
- The pressures of the medium on either side of the plug cannot be equalized if the medium

is discharged into “open air”.

- If adequate pressure equalisation cannot be achieved using a pressure balancing plug,

other design solutions must be used instead (e.g. a bypass line).

ATTENTION !
ARI stop valves must be equipped with pressure balancing plugs if the
differential pressures listed in the table below are exceeded in the closed state.
Valves with pressure balancing plugs should be installed so that the pressure of
the medium acts on the plug (pos. 3) and the stem is vertically upright.

fig. 10

Balancing plug

DN

65

80

100

Pressure difference

P

110 bar

70 bar

44 bar

ATTENTION !
Note direction of flow.