Dover PSG Mouvex AZ O Установка, эксплуатация и обслуживание - Страница 16
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1
PRELIMINARY CHECKS
Make sure that the plastic plugs have been taken away from the ports of the pump and that the pump is
1-1
running (defective drive, damaged motor, etc., faulty transmission : broken coupling, sliding belt, worn or
poorly coupled clutch, etc.).
Make sure that the pump rotates in the correct direction corresponding to the direction in which the liquid
1-2
circulates in the installation (cf. the pump plate). If necessary, change the electric motor connections or
adjust the piping as necessary (diesel engine drive).
Make sure that there is liquid in the tank from which the pump draws and that the end of the inlet piping is
1-3
constantly submerged.
Make sure that the pump rotation speed is sufficient. Determine this by checking the speed of the pump
1-4
motor (see motor plate) and the speed reduction ratio (see reduction gearbox plate) or use a rev. counter.
Check the correct tension of belts.
If these checks do not highlight the problem :
MEASURE THE DISCHARGE PRESSURE (as close to the outlet of the pump as possible, with a mini-
2
mum distance of 5 pipe diameters).
2-1
If the pressure is lower than the figures given for the material, or null, this could be due to :
A poorly adjusted bypass, the valve setting is lower than the discharge pressure (tighten the set screw or
2-1-1
replace the spring after checking that the electric motor is suitably protected).
The bypass valve is not closed ; either the plunger has not returned to its initial position, or there is dirt on
2-1-2
the valve seat.
2-1-3 The pump is worn, this will also affect the suction capacity of the pump (cf 3-2-2 c).
2-2
If the pressure complies with the equipment data (pump speed and motor output) it is possible that :
The pressure required for the given installation to obtain the required flow rate is too high and the flow is
partially or totally circulating via the bypass, or :
a. the height of the discharge is too great (reduce it by bringing the discharge tank to the level where the
pump is). If suction conditions are favourable, the pump can also be moved closer to the discharge tank.
b. that head losses are too high because :
- the piping is unsuitable (too many "bends", too long or the diameter is too narrow) for the process
2-2-1
- of partially blocked piping (valve partially closed, tap partially shut, cloth obscuring flow, etc.).
The discharge piping is completely blocked (valve fully closed, tap completely closed, cloth plugging flow,
2-2-2
full protection seal left by carelessness, etc...), in this case, all the liquid passes via the bypass.
NT 1003-A00 09 18 AZ O e
11. TROUBLESHOOTING
ZERO OR INSUFFICIENT FLOW
conditions : Flowrate, Specific Gravity, Viscosity (this can change considerably with temperature).
Reduce the head losses by simplifying the circuit : reduce of the number of fittings, valves, elbows,
etc... Move the pump closer to the discharge tank or vice versa, if conditions permit. Increase the
diameter of the piping, etc... Reduce the product viscosity via heating. Reduce the flow, etc...
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