Edwards A705-41-000, Инструкция по эксплуатации

Страница: 8 / 82

A705-40-880 Issue B
Page 2 © Edwards Limited 2011. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Introduction
1.3 Shaft-seals purge
Refer to Figure 1 . The shaft-seals purge pipeline (17) delivers a nitrogen purge to the shaft-seals.
This shaft-seals purge system:

Ensures that the shaft-seals are maintained at a positive pressure during pump operation.

Prevents the entry of corrosive or toxic process vapours into the pump gearbox.

Prevents contamination of the process gases by pump oil.

Prevents damage to the shaft-seals by debris.
Accessory kits are available to provide final stage gas ballast and inlet purge facilities on the pump:
refer to
Section 7.4 .
1.4 Temperature control system
Refer to Figure 1 . The pump has an indirect cooling system. Coolant circulates around the pump-body by natural
convection; the coolant then passes through a secondary circuit in the heat exchanger (22). In the heat exchanger,
heat is extracted from the coolant by cooling-water which circulates through a primary circuit in the heat exchanger.
The pump-body has a coolant overflow pipe (20). As the temperature of the pump-body increases and the coolant
expands, excess coolant may be forced out of this pipe. This pipe is coiled up for delivery purposes. On installation
it should be routed to a suitable container. The quantity of coolant ejected will give an indication of whether a top
up is required.
In operation, the pump is maintained at a constant temperature by a TCV (thermostatic control-valve, 7) which
controls the supply of cooling-water to the heat exchanger. The pump-motor (12) is air-cooled.
The cooling-water supply passes through a filter ( Figure 4 , item 10) and then through a pipeline to the heat exchanger
(22). A flow indicator ( Figure 4 , item 11) in the cooling-water return pipeline shows when there is a flow of cooling-
water through the heat exchanger.
The EDP pump has a coolant jacket upper temperature limit that is defined by:

The pump operating limit (for non-ATEX applications).

The temperature classification (if the EDP is part of an ATEX system).
In order to monitor the pump temperature and to provide a means of switching off the pump when the coolant jacket
temperature is too high, the EDP pump will be fitted with one of the following:

A temperature transmitter.

A thermal snap-switch
*
.
Refer to Section 3.6.4 and 3.6.5 for connection details.
*
Non-ATEX systems only.