User Manual

Particulate Monitoring Systems Installation & Operating Manual

4. Particulate Sensor Installation

4.1 Location

The following factors should be considered when determining the sensor location:

 Area Classification

 Flow conditions

 Electrical (Faraday) shielding

 Atmospheric shielding (in the case of ducts and stacks open to atmosphere)

 Access for installation and service

SENSOR LOCATION

• Before installing the sensor, confirm area classification requirements. Do

not install any device that is not tagged suitable for the required area

classification.

• Before installing the particulate sensor, confirm ambient temperature,

process temperature and process pressure requirements. Do not install any

device that is not tagged as suitable for the required temperatures or

pressures. Confirm compatibility of wetted and non-wetted materials.

• For hazardous areas, a maximum ambient temperature of the particulate

sensor enclosure must not be exceeded. Refer to the Temperature

Considerations section for full details.

It is essential for the pipe/duct to provide an electrical (Faraday) shield for the sensor. It is therefore

required that the pipe, duct or stack is metal and earth grounded (small inline tubing sensors provide

their own section of metal pipe which also must be grounded). Consult the factory when insertion

probe style sensors are to be installed in non-conductive pipes, ducts such as plastic or fiberglass.

The particulate sensor must be installed in a position where the flow is reasonably laminar and the

particulate is evenly distributed. The ideal position is where the pipe/duct is straight and free of items

such as valves, dampers or other flow obstructions for a length of 4 diameters or longer. Horizontal or

vertical sections are acceptable. For basic flow/no flow detection it is not necessary to select a

location with a long straight section if access has to be sacrificed dramatically. For trending and

measurement the need for a straight section and laminar flow increases. The particulate sensor should

be positioned with approximately two thirds of the straight section upstream of the sensor and one

third downstream. The particulate sensor should be located in the center of the pipe/duct. If the

pipe/ducting is square it should be located in the center of one of the sides. In either case, be sure the

position is such that the tip of the sensor reaches the midpoint or beyond. Always use good

engineering sense and be sure the sensor will interact with a reasonable representation of the flow.

For emissions detection applications such as baghouses or cartridge collectors, good locations are

generally found upstream of the blower. The particulate sensor can be located downstream of the

blower but not too close to the stack outlet. There must be sufficient duct downstream of the sensor to

provide adequate electrical and atmospheric shielding. The sensor should be located upstream of any

sampling ports by at least two feet. It is not necessary that the sensor be in the same section of the

duct/stack as the sampling ports. Particulate sampling ports require fully-developed laminar flow and

longer straight sections.