High duct-static pressure creates problems during a building fire when fire dampers close. Closed fire dampers cause downstream duct sensors to detect a drop in pressure. The duct pressure sensors in turn send signals to crank the air handler even faster to get back up to normal operation. Because the fire dampers are closed, when the air handler ramps up, the duct pressure upstream of the fire dampers will increase to a point where a high static pressure switch will cut power to the VFD (variable frequency drive) and send a signal to the DDC (direct digital control). Switches in this application — by specification — are all manual reset and require two outputs: one for cutting power to the VFD and one for sending the signal to the DDC.
Are you having problems with your current lift station level controls? Dwyer Instruments may just have the cost effective solution you need. In this article we will review several level sensing strategies, the advantages and disadvantages of each, as well as an option you may want to consider for your next project.
Lift Station Basics
In an ideal gravity fed wastewater collection system, sewage would flow downhill from its point of origin in residential or commercial areas to its final treatment plant destination. Due to a number of factors including total distance, topography, geology, economics, etc., the ideal piping design is not always feasible. Therefore, in most cases, sewage flows downhill to a lift station where it collects and then is pumped to a higher elevation in order to begin its downhill journey again. Continue reading “Lift Station Level Sensing”
As the year comes to a close and we celebrate this time with our families and friends, all of us at Dwyer want to give a big thank you to the customers and teammates that we’ve depended on throughout the year. We certainly couldn’t have done it without you.
This year has been unlike any other, to say the least. The COVID-19 pandemic shook the world as hospitals and emergency personnel struggled to keep up with demand for ventilators and isolation rooms. Worldwide manufacturing slowed, as non-essential businesses shut down and companies shifted to CDC guidelines and recommendations. Continue reading “Happy Holidays | Year in Retrospect”
As industries such as building automation and water/wastewater become more energy-efficient, powder and bulk is also increasing energy efficiency using pressure transmitters and variable frequency drives. Pressure transmitter demand is also growing due to more stringent regulations in hazardous environments, where remote control and specialty housings must be available.
With a typical dust collection system, a pressure sensor (such as our Series A3000 or Series DHII) can measure differential pressure across filter bags. The sensor then sends a switched signal to a timer board (such as the Series DCT500A or DCT1000) to signal a filter cleaning. Pressure in the system is created by a blower, typically positioned near the filter banks on top of the hopper. The system can also use a level switch (like our Series PLS and Series CLS2) to signal a full hopper and possibly open a valve to empty the hopper. So how do pressure transmitters reduce energy consumption? And how can you prevent an explosion in a hazardous environment without the additional cost of specialty enclosures? Continue reading “Pressure Transmitters: Increasing Efficiency and Safety”