This article is a continuation of Pressure; Getting Water to Where It Needs to Go.
Whether elevated or underground, water delivery systems work at their best when operators continually monitor the water’s pressure, level, and temperature. Structural health is also important. The gauges and sensors used in water tower applications must be able to withstand heavy vibration, temperature extremes, and of, course, moisture.
Water pumps, pipes, and storage tanks are expensive, vital investments for any municipality. To protect the entire infrastructure and to ensure the reliable delivery of drinking water, use measuring instruments designed to operate under challenging conditions.
A-10 pressure transmitter
Pressure Instruments for Water Delivery Systems
A range of pressure gauges and sensors help monitor the pumps that lift water to the elevated storage tanks, as well as the pipes that carry water to and from the tank. Since pumps and their motors create significant vibration, pulsation, and pressure surges that can damage standard instruments, the gauges and sensors used in this application must be able to withstand wide pressure variations.
The A-10 pressure transmitter is highly resistant to pressure spikes and vibration, thanks to thin-film technology and an all-welded stainless steel measuring cell. It is cost-effective, making this transmitter ideal for OEMs, and has an extremely compact design to fit in tight spaces. When installed at the suction (inlet) side of a pump, the A-10 helps prevent cavitation, which can cause pressure spikes. For the most demanding pressure measuring requirements, use the S-20 superior pressure transmitter.
UPT-20 process transmitter
Model UPT-20 with pressure port and HART communication protocol is the recommended universal process transmitter for use with either the A-10 or S-20. It is constructed of stainless steel or stainless steel and PBT plastic, and all wetted parts are made of welded stainless steel with no internal O-rings, gaskets, or other soft sealing materials. The UPT-20 is available with a variety of certificates (NACE MR0103 and MR0175, NIST traceable accuracy, DKD/DAkks calibration per IEC 17025, etc.) and is CE and RoHS compliant.
111.25DW pressure gauge
For gauges that do not come into direct contact with drinking water, use one of WIKA’s heavy-duty XSEL® models. The 21X.34, 23X.34, and 26X.34 feature Swiss-made movements and hardened components that reduce stress and wear – making these gauges an economical choice with their long service life. Liquid case filling offers even greater protection against vibration, pulsation, and pressure surges.
CPT6020 pressure transducer
Level Measurement in Water Towers
Underground storage tanks, which are not gravity-fed, can use submersible pressure sensors for level measurement. For above-ground water tanks, however, a pressure transmitter like the A-10 or S-20 – installed on the discharge pipe – can measure the hydrostatic pressure of the water column above that point.
For even more precise level measurement, use a digital pressure transducer like the CPT6020. It is a self-contained pressure sensing device, meaning that it incorporates a low-hysteresis silicon sensor with electronically compensated pressure linearity over the entire compensated temperature range. This calibration-grade instrument has a ±0.020% full-scale accuracy.
Temperature Instruments for Water Towers and Pumps
Municipalities in the north have to deal with cold-weather situations. In addition to plowing snow and de-icing roads, there’s the matter of keeping water tower piping from freezing. Some cities get around the issue by storing treated water below the frost line – around 6 feet deep at 45° latitude. But underground storage is an expensive solution. Not only does it require extensive engineering and excavation at the project outset, but also calls for many pumps operating nonstop to deliver water to customers. In contrast, water towers are much more cost effective to construct, operate, and maintain.
Due to the tanks’ depth, the water inside usually won‘t freeze completely, and any ice that does form is at the top – rising and falling alongside the water level. The piping is another matter. Insulation and heat tape prevent a water tower’s riser and discharge pipes from freezing, and the warmed water entering the tank slows down the freezing process. Resistance thermometers (RTDs) in wireless transceiver nodes help monitor temperatures in key locations throughout water tanks.
TR58 bearing RTD
RTDs are also invaluable for monitoring the condition of high-pressure water pumps, as increasing temperature can indicate that the motor is overheating – a potentially dangerous and costly problem. The TR58 bearing RTD has a solid design with no moving parts, making it vibration-proof. Its compact design allows it to fit in tight spaces like bearing plates, shafts, and motor windings. It can also be spring-loaded into the bearing’s housing.
Wireless Sensors for Condition Monitoring
At the heart of a municipality’s water delivery system, pumps are expensive yet vital pieces of equipment. Therefore, it is essential to ensure that their motors remain in good working condition. Wireless, easily configurable, and simple to install, Leap Sensors by Phase IV Engineering help users keep an eye on the state of their pumps and other rotating equipment with one transceiver node that measures a variety of parameters:
- Vibration
- Activity – running or not running
- Temperature – via thermocouples and/or RTDs
- Pressure
- Differential pressure – for filter monitoring
- Flow – via ultrasonic bolt-ons and/or pulse counter
- Moisture – humidity level, water, flooding
- Analog input – 4…20 mA (current), 0…10 V (voltage)
- Electric current draw
- Digital input – CAN, RS485 (Modbus RTU), SPI, 12C, etc.
- Strain and load – via force sensors
All this data is transmitted using gateways or directly to cellular, and is fed into the LeapSensorManager software, located on the gateway, a PC, a local server, Phase IV’s cloud server, or the client’s cloud server. This software analyzes the data and sends alert – via text, email, or phone call – if it detects an issue.
Leap Sensors for wireless condition monitoring of water delivery systems
Structural health monitoring in water towers
Water tanks can hold a tremendous amount of weight – from about 40,000 lb. in a 5,000-gallon rooftop units to over 20 million lb. in a 2.5 million gallon composite elevated tank. Structural health monitoring (SHM) is a key factor in infrastructure safety, especially for larger storage tanks.
Traditionally, civil engineers visit the site – be it water towers, bridges, overpasses, or tunnels – at regularly intervals to manually check for potential problems. Scheduled SHM is fine, but what if the tank begins to lean or shift between annual or biannual inspections, or the engineers missed something critical?
A more reliable way of monitoring a structure’s health is with wireless sensors, which continually measure strain, incline, vibration, crack propagation, and other variables, then automatically report any significant or sustained changes to operators. Not only does automated SHM increase the safety and reliability of elevated water tanks, but catching potential problems early saves on maintenance, repairs, and the cost of labor.
WIKA, Smart Sensors and Solutions for Municipal Water Utilities
The mission of every municipality’s water service is to provide a clean and reliable supply of water for their community at a reasonable cost. Tank manufacturers, EPC (engineering, procurement, and construction) firms, and contractors also want to equip water delivery projects with the highest quality instruments and sensing technology. WIKA is a global leader and trusted partner for measurement solutions in water towers, pumping stations, water treatment plants, and other municipal facilities. Contact the product experts at WIKA USA to help you select the right measuring instruments and sensors that will protect your assets and prolong their service life.
Products mentioned in this article
• A-10 pressure transmitter
• S-20 superior pressure transmitter
• UPT-20 process transmitter
• Drinking Water (DW) series: 111.10DW, 111.12DW, 111.25DW, and 213.53DW
• XSEL® process gauges 21X.34, 23X.34, and 26X.34
• CPT6020 digital pressure transducer
• TR58 bearing RTD
• Leap Sensors