Chapter 3
– Mechanical & Electrical Installation
15
FT742-DM (4-20mA)
– Sensors
- User Manual
The mounting pipe should have a minimum galvanising thickness of 50μm to ensure long-term protection
against corrosion (a relevant galvanising design standard should be considered, for example ASTM A123 or
ISO 1461-2009). Aluminium components of the appropriate grade could be used as an alternative.
At the base of the sensor the mounting pipe meets the sensor (visible when viewed from below). The contact
surface ring (see Figure 8 left image) is hard-anodised and unsuitable for electrical grounding between the
sensor body and ground. This connection should be checked as part of the annual inspection of the sensor as
detailed in Section 4.2. The FT035 grounding accessory can be fitted within the connector chamber and can
provide a low-resistance grounding path to the outer edge of the mounting pipe. The FT035 is comprised of a
coiled metallic spring fitted within the circular inner wall, mating with the outer edge of the mounting pipe, it can
be viewed from the below viewpoint:
Figure 8: Direct-Mount
– Connector (View From Below and FT035 Location)
The following replacement parts are available:
FT027
O-ring (3.53 CS x 32.92 ID)
FT031
Size Adaptor 25mm (1”) for FT742-DM (includes a FT033 tapered pipe insert & 4x FT034
self-locking fasteners)
FT032
Size Adaptor 50mm (2”) for FT742-DM (includes a FT033 tapered pipe insert & 4x FT034
self-locking fasteners)
FT033
Tapered Pipe Insert (33.7mm OD)
FT034
1x Self-locking Fastener
FT035
Grounding Accessory
