Dover PSG Mouvex AZ O Instalação, operação e manutenção - Página 18

Procurar online ou descarregar pdf Instalação, operação e manutenção para Bomba de água Dover PSG Mouvex AZ O. Dover PSG Mouvex AZ O 19 páginas.

11. TROUBLESHOOTING (continued)

These noises can be caused by hydraulic and mechanical sources. They can be distinguished by the fact

that only the former disappear (or at least lessen) when air is allowed into the inlet pipe.

HYDRAULIC NOISES

These noises can come from insufficient product being supplied to the pump, or :

- the rotation speed is too high for the installation conditions (increase of viscosity due to a change of

7-1

product or a reduction of temperature, etc.).

- that the suction head is too high or has become too high due to excessive head losses following clog-

7-2

ging of the piping or filter, a change of viscosity of the liquid, etc.,

7-3

- an increase of the vapour pressure with a rise of temperature.

MECHANICAL NOISES

These can stem from :

- the bypass valve knocking on the seat when the discharge pressure is close to the bypass adjustment

8-1

pressure (turn the adjustment screw after making sure that the electric motor is suitably protected).

- abnormal stress on the pump : the transmission is pulling on the shaft, pulling on the flanges by the

8-2

piping.

8-3

- a broken part or foreign body has entered the pump.

The most spectacular event occurs when a diesel engine stalls or the power to an electric motor is shut off.

If this incident occurs when closing the discharge line, the cause may be :

a. the bypass is assembled back to front.

9-1

b. the bypass is adjusted too tight.

c. the motor protection is adjusted too low or wrong circuit breaker have been fitted.

If the incident occurs during operation, the cause could be :

a. an inadequate motor (in this case, the discharge pressure complies with what was expected).

b. head losses higher than expected - following higher viscosity or specific gravity than planned initially

(in this case, the discharge pressure is higher than that planned. The pressure can be reduced by

9-2

loosening the bypass adjustment screw - the flow is decreased).

c. excessive speed of rotation.

d. a fault of the equipment (faulty alignment, deformation of the chassis, stress exerted by the piping on

the flanges, seizing, etc.).

Excessive consumption of electricity can also be due to a poor motor connection (e.g. a 3 phase motor

operating on 2 phases).

NT 1003-A00 09 18 AZ O e

ABNORMAL NOISES

EXCESS POWER CONSUMPTION

18/19