Flow Velocity Air and Liquid level Sensor Installation Method

In this Article we are going to discuss about Flow Velocity Air and Liquid level Sensor Installation Method , this is Sensor's Installation Methods video series part 3

General notes for all sensors

• Do not install sensors so that they protrude in any direction, and do not suspend them below the horizontal.

• Ensure that they are protected against damage and vandalism and will not cause injury.

• Be aware of the effects of orientation on the functioning of the sensor.

Always determine the following before mounting:

1. Minimum or maximum  ambient Temperature
2. Ambient humidity and exposure to spray water
3. Exposure to vibration
4. Explosion protection
5. External influences

• Take account of the active and inactive sections of a sensor probe.

• A tight-sealing test-hole must be provided adjacent to every sensor.

• The cable should be installed with a drip loop to prevent water from entering the sensor housing.

• If the sensors are to be concealed (e.g. in false ceilings, shafts etc.), mark their locations visibly and record them in the site documentation.

• Always allow a sufficient length of spare cable so that the sensor can be removed at any time without disconnecting the wiring.

• When installing a sensor, avoid compressing the lagging.

• Use a graduated-diameter mounting flange to avoid compressing the lagging.

• If the mounting flange supplied does not have the appropriate graduations, use spacing bushes to avoid compressing the lagging.

• Fix a labeling plate in the direct vicinity of the sensor.

• This must include a plain text description and the reference number, which appears in the plant schematic. Do not attach the label to the device itself.

 Flow velocity  Air:

• The pressure-tapping point must not be located in turbulent air.

• Ensure sufficiently long settling-zones upstream and downstream of the tapping point.

• A settling-zone consists of a straight section of pipe or duct, with no obstructions.

Fan-belt monitoring :

The differential pressure across the fan is only suitable for fan-belt monitoring.

• Negative connection (–) on suction side use copper tube.

• Positive connection (+) on discharge side: use Pitot tube.

Flow monitoring:

• Electro thermal flow detectors must be installed in a zone with a high flow velocity, e.g. where pipes narrow.

 Differential Pressure :

• Do not monitor flow or differential pressure where flow resistance is variable, e.g. at filters, cooling coils, fans etc. Suitable locations: heating coils, silencers, baffles, attenuators.

Formula: dg = Equivalent diameter

Flow monitoring Water :

• If differential pressure is used to monitor the flow, it is important to ensure that there are no stop valves or balancing valves between the sensing points.

Air quality Room Sensors:

There are two types of air quality sensors: 

Mixed gas or (VOC) sensors 

• The accumulation of up to 24 different gases is measured in the ambient air (total concentration measured)

Selective gas sensors :

• These measure only one gas (e.g. CO2) in the ambient air (selective measurement).

• Do not locate temperature or humidity sensors above or below the AQ sensor.

• The heated sensor element produces significant intrinsic heat in the device.

• Owing to this characteristic, the room temperature or room humidity must not be measured in the immediate vicinity.

• Maintain a clearance of minimum 60 mm on each side of the AQ sensor.

 CO2 sensors

• Selective gas sensors may require maintenance at regular intervals.

• Please consult the manufacturer’s instructions.

• The sensor must be installed in an accessible location.

• Avoid recesses (e.g. shelving) and alcoves.

• Do not install directly adjacent to doors.

• Do not install behind curtains.

• Seal gaps between cable/plastic tubing and conduit.

• Otherwise measurements will be falsified by incorrect circulation of the air.

Liquid level Sensing:

A distinction is made between the following methods:

• Capacitive measuring probes
• Pressure/differential pressure (hydrostatic)
• Ultrasound
• Tank weighing systems
• Electromechanical sensing.

 Pressure measurement:

• The pressure is defined by the height of the liquid medium, measured from the sensor to the surface of the liquid.

• There are no critical factors to consider when installing the pressure sensor.

• The sensor material must be suitable for use with the liquid medium.

 

Bubble technique:

• The pressure measurement is determined by the height of the liquid above the bubble-tube outlet.

Floats:

• These are used in open and sealed systems.

• The device head must be installed above the maximum expected liquid level.

 

Tank weighing system :

• The measured result is determined by the tank content (mass weight).

• The sensor should be mounted in accordance with the manufacturer's instructions.

Capacitive measuring probes :

• These are used in open and sealed tanks.

Mounting: 

• The distance from the next electrically conductive component must be as specified by the manufacturer.

Conductance systems:

• These are used in open and sealed tanks.
• The measured result is determined by the length of the immersed electrodes.

Mounting: 

• The distance from the next electrically conductive component must be as specified by the manufacturer.

 Magnetic level switches:

• These are used in open and sealed tanks.

Mounting :

• The liquid-level tube and the location of the level switch are determined by the manufacturer.

• Level switches are installed at the same height as the required liquid level.

Hydrostatic level sensing:

• The measurement is based on the maximum liquid level and the location of the sensor.

 

Will we hope this Article is useful to you , Thank you for visiting our Blog , we will meet in an another good Article.