4 INSTALLATION
4.1PRELIMINARY CHECKS
The MSM400 system is normally supplied in two packages, one for the MSM400 Control Unit and one for the sensor, whether it is a pipe section or a tank sensor. Take care in handling the pipe section. In particular do not damage the cable or the hose protection for the cable where it enters the sensors. Before installation check that there has been no damage in transit, particularly to the sensor cables. Check that the equipment is as specified, and that the pipe section length and flanges are compatible with plant pipework.
Sensors in intrinsically safe systems may be mounted in potentially explosive areas ("hazardous areas"). Refer to the sensor safety data section 2.4.
The control unit must be mounted in a
4.2PIPE SECTION INSTALLATION
The Mobrey MSM448 pipe section sensor should be same size as surrounding pipe work. It should be installed in a straight section of line, if possible, with the sensors in a horizontal plane. This avoids the sensors being covered with debris at the bottom of the pipe, and being in an air gap at the top of the pipe. Particular attention must be paid to the positioning of the pipe section in relation to pressure reduction or agitation of the slurry to be monitored :
Pipe line
Pipe line
Sensors horizontal in pipe OK
Sensors vertical in pipe NOT OK Sludge settles on bottom sensor Top sensor probably in air
Figure 7 : Pipe sensor orientation
WARNING:
Air or gas that comes out of suspension in a slurry gives a high ultrasonic attenuation, giving a false high solids reading. The installation must maintain the full hydrostatic pressure in the slurry up to the pipe measurement section. Any unnecessary pressure reduction should be avoided. This means avoid free fall of the slurry into a sump, avoid pumps and partly open valves, avoid abrupt changes of pipeline diameter upstream of the sensor pipe section installation point. If possible position the sensors directly at the outlet of the tank, low down, so that the full hydrostatic head is maintained on the monitored liquid. However, it may be necessary to remove the sensors for face cleaning later, so isolation valves are desirable. The Mobrey Sensor pipe is supplied with a flushing spray nozzle, which directs a supply of water at the sensor faces. This is a useful cleaning procedure, avoiding the need to remove the sensors from the pipe. A water supply is required, connected to the purge nozzle on the top of the sensor pipe section.
4.3SUSPENDED SENSOR INSTALLATION
The Mobrey MSM433 sensor is available with the gap between sensor faces from 100 mm up to 450 mm, for higher sensitivity to light slurries. These sensors are usually mounted directly into the settlement tank, at
IP258
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