GORMAN-RUPP VG3B3-B, Инструкция по установке, эксплуатации и обслуживанию

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Installation Operating and Maintenance Guidelines T-Rack vario 3(2012-05) E inge
Page 19
© 2011 inge GmbH ▪ All rights reserved
The Air Integrity test (pressure hold test) process for inge Ultrafiltration modules within
the T-Rack is shown in Fig. 5.1 and executed as follows:
1 Empty the feed line
Pressurize the complete feed side with dry, oil-free compressed air (1000 mbar). The raw
water side (top) of the module must be open to atmospheric pressure. The pressure will
cause the water on the feed side to pass through the membranes to the raw water side. In
principle, air cannot pass through the intact membranes due to the surface tension of the
water in the membrane pores (note that this does not take diffusion processes into
account). The time required to empty a rack depends on total rack size, the volume of the
connected pipework and the compressor capacity. In our experience, the process of
emptying the feed side takes approx. 10 minutes.
2 Close the air pressure valve
When the feed side has been drained completely and a stable pressure of 1000 mbar has
been reached and maintained for at least 1 minute, close the air supply to the feed side.
3 Idle time
4 Measure the pressure drop
Measure the pressure drop on the feed side for at least 3 minutes. Due to the air diffusion
process through the water-filled pores of the membranes, a slight pressure drop may be
observed which should not be regarded as membrane leakage. This diffusion effect may
also result in a minor degree of bubble formation becoming visible in the transparent pipe.
In practice, pressure drop rates are less than 10mbar/min for all rack sizes. In the event
that this base value is exceeded, it is advisable to conduct a detailed examination to
identify the cause. The base value is dependent upon various factors, including the hold-up
volume, the tightness of all the valves and fittings and the diffusion component of the
module.
Determination of the base value must be performed using new modules (i.e. modules that
are being used for the first time) in the fully assembled rack. This value is then used as a
reference value (documentation).
Any leakage in the module can be detected using the integrated transparent pipe on the
filtrate side (Fig. 5.2). In the event of a leak, a continuous stream of air bubbles of a
steady intensity will be visible during system air integrity testing. It is essential to ensure
that the upper filtrate side is open, unpressurised and completely filled with water during
air integrity testing.
If integrity testing has ruled out any other sources of error, a significant and permanent
stream of air bubbles is visible in the transparent pipe, and the pressure drop is greater
than 10 mbar/min, it can be assumed that the system has a capillary defect.