Double Safety Relief Valve; Suction And Discharge Pipes; Forces And Moments - Johnson Pump TG GS2-25 Instruction Manual

3.18.5 Double safety relief valve

When a double safety relief valve is installed three arrow plates are attached – one on each valve
(A and B) indicating the liquid flow direction of each valve (small arrows 2 and 3) and one on the
Y-casing (C) indicating the most favourable direction of rotation of the pump (arrow 1).
The two suck-back grooves (D) will help
to evacuate air or gases during start-up
or whilst running. As they only function
in one direction of rotation, the Y-casing
should be positioned in such a way that
the suck-back grooves (D) are placed
towards the most used suction side.
In case of doubt, contact your local
supplier.
Be sure that the safety relief valves are
mounted opposite each other so that
the arrow plates on the safety relief
valves (A and B) are indicating opposite
liquid flow directions.

3.18.6 Suction and discharge pipes

3.18.6.1 Forces and moments

Note! Excessive forces and moments on the nozzle flanges derived from piping can cause
mechanical damage to pump or pump unit.
Pipes should therefore be connected in line, limiting the forces on the pump connections.
Support the pipes and make sure they remain stress-free during operation of the pump.
M
F
z
See table for maximum allowable forces (F
on a solid foundation (e.g. grouted base plate or solid frame).
When pumping hot liquids attention should be given to forces and moments caused by thermal
expansion in which case expansion joints should be installed.
Check after connecting whether the shaft can move freely.
A.0500.501 – IM-TGGS/05.01 EN (03/2013)
F
y
M
y
z
A
D
TG GS pump size
2-25
3-32
6-40
15-50
23-65
58-80
86-100
185-125
M
x
F
x
) and moments (M
x, y, z x, y, z
3
B
C
F (N) M (Nm)
x, y, z x, y, z
2000 315
2050 325
2200 385
2600 675
2900 800
3550 1375
4100 1750
5900 3750
) on the nozzle flanges with pump
1 2
31