LumaSense Technologies M67 - Manual (Page 22)

M67, M67S Manual
21
7.3 Jacket with coolant circulation
It is also possible to purchase a protective jacket with provisions for circulation or coolant to control the temperature around the
INFRADUCER. Coolant at the prescribed inlet temperature ensures that the instrument remains at a safe, constant temperature.
As noted in section 6.5, page 17, the coolant temperature must be above dew point of the air around the INFRADUCER to
avoid the possibility of erroneous readings caused by moisture condensation. The objective is to achieve a temperature within
the normal ambient compensation range of the INFRADUCER.
Note that the most common cause of detector failure is overheating and that use of a jacket with an extremely reliable coolant
circulation system is the only way to ensure your system operates according to design (if the instrument is subjected to high
ambient temperatures). The coolant should be drawn from an uninterruptible supply, which operates independently of the
process being monitored. Coolant lines should not have hand operated isolation valves which could be shut off accidentally.
The flow rate of the coolant should be adjusted using needle valves, which cannot be shut off completely.
Coolant piping should be designed to be of sufficient size (1/2" is recommended) to ensure that the bulk of the pressure drop
occurs in the flow control elements of the cooling circuit, and to avoid clogging of the pipes due to mineral deposits.
The jacket has two 1/8" NPT female connections. It may be mounted in any position and either connection used as the inlet. A
rotameter or other visual flow-indicating device is highly recommended. Also, it may be desirable to install a flow switch
coupled to an alarm to guard against total flow shut-off.
If the adjustable bracket is used to enable variation of the aiming angle of the INFRADUCER axis, consult Figure 14. If a fixed
mounting is desired, the figure also shows the relevant fixed mounting details.
Figure 14 - Protective Jacket Assembly With Aiming Flange Mount