A large municipal water treatment plant was using an antiquated, piecemeal pressure monitoring system in their Sodium Hypochlorite Feed Room, because at that time there were not many other options available.

Sodium Hypochlorite is a caustic chemical used in the water disinfection and purifying process to release free chlorine, killing any pathogens which may pass through the filters. Because of its corrosive nature, instrumentation must be protected from the medium to prevent damage.

The system the plant was using to monitor feed pressure consisted of a heavy analog gauge with a diaphragm seal, along with a mechanical switch for shut-off protection. The weight of the analog gauge and diaphragm made mounting to the PVC piping difficult.

Moreover, the pipe was prone to bending and cracking under the weight of the instrument, significantly increasing the risk of leaks and spills. A metal clamp was used to reinforce the connection point.  An additional fitting was also necessary, to extend the gauge from the diaphragm to allow installation of the switch. This added more weight on the piping, and added possible leak paths in the assembly.

This instrumentation was not only frequently inaccurate but experienced multiple failures, some right out of the box. It was a clumsy and imperfect system, but it was the only method available to this plant at the time.

The old system used heavy analog gauges. NOSHOK replaced these with highly accurate electronic indicating pressure transmitters with two alarms, protected by a corrosion-resistant, plastic threaded PTFE diaphragm seal. By the use of proven ceramic sensors, this pressure transmitter delivered a high level of repeatability and durability, which in addition to its compact size and light weight provided a significant advantage over the previous instrumentation.

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Its smaller footprint and reduced weight also significantly decreased possible leak paths, increasing safety and efficiency.

The NOSHOK transmitter’s digital indication is extremely accurate with a fast response time. With no moving parts to wear out, this instrument provides a far extended service life over analog mechanics. 

A long list of added benefits includes pressure ranges from 0 to 7,500 psig, a 330° rotatable display head, 7 different available output configurations, and simple 3-key programming. The RoHS compliant transmitter/alarm also allows user selectable switch time delay and the programming of set points without applying pressure. The instrument and diaphragm seal are used in conjunction with a power supply and Form C relays to easily integrate into the plant’s current system. 

The mechanical switch that the plant was previously using was replaced with NOSHOK’s much more accurate, repeatable, and longer lasting electronic transmitter/switch.

The NOSHOK solution was a significantly streamlined package that provided a much more accurate, reliable and trouble-free pressure measurement process for this water treatment plant. The system also has a low voltage connection for easy removal.

With the NOSHOK solution, this plant seamlessly solved its feed pressure monitoring issues, reducing leak paths and increasing safety in their Sodium Hypochlorite Feed Room.