Vertical Stack Block Sewer Detection

Vertical stacks are often forgotten, yet can be the worst kind of sewer blockage.  Many tower blocks for example have vertical stacks, and a blockage half way down can be messy and costly, but they can be mitigated

Monitoring vertical pipework can be extremely proactive.  Should a blockage occur in a system of this nature, identifying it early can often save a host of outcomes which are invariably expensive.  Following the success of the blocked sewer monitoring probes, we have gone on to develop a device for vertical stack.  Do note however, we have some clients who are applying this technology on horizontal falls from toilets and showers.

Please see the below product outline.

Fundamentals:

The system operates using an ultrasonic transmission (through fluid) technique similar to that used in ultrasonic body scanners, however there are two separate transducers, one that emits and one that receives ultrasound strapped on opposite sides of the pipes linked by a cable to a central battery powered control unit and transmitter unit.

Operation Principle:

The control unit is pre-configured to activate the ultrasonic transmitter transducer every 5-minutes. Each 5 minutes it emits a high frequency totally inaudible ultrasonic pulse. This pulse travels into the pipe and through its wall. If the inside of the pipe is empty, partially full or has a normal flow, the vast majority of the signal is reflected back and lost in the wall of the pipe. However if the pipe is completely full due to a blockage a portion of the signal is able to couple into the fluid (sewage), travel through the fluid and pass across the pipe to the opposing side  where is couples into the wall and out to the receiving ultrasonic transducer.

The receiving transducer contains a sophisticated amplifier and filter circuit that removes background noise from fans, pumps etc, it also includes a high gain amplifier that boosts the received signal for processing, where the received signal is compared against the frequency of the transmitted signal as a final stage of the blockage verification process.

If the unit finds that the pipe is clear is triggers the transmitter to emit an OK signal appended with the units ID whereas if the pipe appears blocked the unit emits a blocked signal plus a number that increments for every 5-minutes that the pipe is blocked.

The broadcast signal is received at the data concentrator where it can be interfaced with the sites BMS system or uploaded to a web-server where the status of the stack / pipes can be observed alongside other sewer and facility management sensors such as the BDT blocked sewer detectors.

Finally, once the blockage is cleared the counter is reset and the unit reverts back to the OK message.