Partech - Model ASLD2200 -Sludge Blanket Monitor

Continuous monitoring of the sludge/water interface or sludge blanket is central to the efficient operation of clarifiers, thickeners and settlement tanks. Reliable measurement enables a control system to maintain the optimum depth of sludge in the tank. A sludge interface that is too high can result in pollution incidents caused by carry-over from a final settlement tank. The sludge can also become too thick to extract easily or can turn septic if left too long. If there is insufficient sludge in the tank the settlement process cannot operate correctly and the solids will tend to remain in suspension.

Our infrared sensors are ideally suited to monitoring the sludge/water interface even when the settlement process is not working effectively and the interface has become indistinct.

The ASLD2200 is supplied with a sensor that uses infrared attenuation as the principle of operation which allows Partech to ensure sufficient sensitivity to monitor sludge blankets in a wide variety of applications. It should be noted that sensor selection can be site dependent. Partech are happy to provide full support in the selection of the correct sensor.

The sensor will normally be positioned in the area of the tank just above the sludge and will therefore be kept away from the worst of the fouling that can occur in the treatment of either potable or dirty water. Provision must be made for transmission of the output signal to the control system; this is normally possible via spare slip rings. Where this is not possible a radio telemetry option is available, allowing transmission directly to the control system without the need for installation of cables.

When monitoring the Sludge Blanket Level in settlement tanks it is important to ensure that the sensor is sensitive enough to detect low density solids before ‘carry-over’ to the next process stage occurs, ensuring that potential pollution events are highlighted prior to occurrence. At the same time the sensor should not be ‘blinded’ by solids in the supernatant.

• Final Settlement Tanks
• Clarifiers
• Primary Settlment Tanks

• Simple Operation
• Low Cost of Ownership
• Continuous Output

Physical

• Dimensions (hxwxd) : 490 x 350 x 382 mm
• Weight : 15 kg
• Protection Class : IP55 Outer Enclosure with IP65 electronics housing
• Enclosure Material : GRP Outer Enclosure with Polycarbonate inner
• Cable Entry : 3x M20
• Cable Core Size : Max Conductor Size 2.5 mm²

Electrical :

• Power Supply : 85 to 264 VAC 47-65 Hz
• Power Rating : 25W

Environmental Data :

• Operating/Storage Temperature : 0 to 50ºC
• Location : Indoor/Outdoor

User Interface :

• Display : 3 Digit, 7 Segment LED Display of 0-100%
• Setup : Potentiometer and Push Buttons on main PCBA
• Units of Measurement : %age Depth

Output Signals :

• Analogue Output : 4-20 mA, max load 500 ohm
• Relays : 1, set at 0 and 100% and is not adjustable
• Contacts : Contact Closure, 0.55 A @ 100VDC
• Local Annuication : 6 LED`s on main PCBA

There is a choice of sensors for use with the ASLD2200, all the sensors use infrared attenuation as their operating principle, this makes them sufficiently sensitive for use on thin water treatment sludges as well as the more usual sewage treatment applications.

Physical

• Dimensions (hxwxd) : 490 x 350 x 382 mm
• Weight : 15 kg
• Protection Class : IP55 Outer Enclosure with IP65 electronics housing
• Enclosure Material : GRP Outer Enclosure with Polycarbonate inner
• Cable Entry : 3x M20
• Cable Core Size : Max Conductor Size 2.5 mm²

Electrical :

• Power Supply : 85 to 264 VAC 47-65 Hz
• Power Rating : 25W

Environmental Data :

• Operating/Storage Temperature : 0 to 50ºC
• Location : Indoor/Outdoor

User Interface :

• Display : 3 Digit, 7 Segment LED Display of 0-100%
• Setup : Potentiometer and Push Buttons on main PCBA
• Units of Measurement : %age Depth

Output Signals :

• Analogue Output : 4-20 mA, max load 500 ohm
• Relays : 1, this alarms at 0 and 100% and is not adjustable
• Contacts : Contact Closure, 0.55 A @ 100VDC
• Local Annuication : 6 LED`s on main PCBA