Industrial pumps are engaged in multiple industries, including chemical, upstream and downstream oil and gas, and power, among others. They are used in production and transport of fluids and gases affecting throughput and profitability. With so much at stake, it is important that end-users protect their pumps.

Overpressure and over-temperature are common causes of pump damage. Depending on the size and type of pump, it could cost between 25k and 50k or more to rebuild a damaged pump. Rebuilding pumps is not only costly but results in lost production. That is why keeping a pump operating under tough conditions such as vibration, shock, pressure spikes and temperature swings are key to long-term pump health.

Preventing Expensive Pump Damage

End-users typically look for reliable shutdown devices to guard against costly pump failure. Some devices like pressure and temperature switches protect the pump when a predetermined pressure or temperature threshold is reached. Other devices like a transmitter, monitor pressure and temperature and send those readings to a PLC programmed to initiate an appropriate response.

United Electric Controls (UE) offers a portfolio of pump protection devices, including its hybrid electronic switches. And the cost of these devices – from a couple of hundred dollars to under a thousand dollars – is considerably less expensive than a full repair or purchase of a new pump.

1. Electromechanical switches. These provide the fastest response (~5 mS) to a process change, which is perfect for positive-displacement pumps. Switches like UE’s 100 Series and 120 Series have been proven-in-use for decades and offer easy installation and set-up but require periodic maintenance. Pump specific models with wide adjustable deadband protect against pump cycling.
2. Electronic switches. Electronic switches are 100% programmable across set point and deadband. They are fast responding at <100 mS. UE’s Excela and ONE Series electronic switches include a unique trip-delay feature that eliminates false trips that can cause unnecessary shutdown and lost production. The ONE Series can communicate self-diagnostic information about device health, resulting in reduced maintenance compared with traditional electromechanical switches.
3. Transmitters. Transmitters monitor process variables and require connection to a PLC for an actionable response. Due to processing time lags, response time is typically slower at ~400 mS – still fast but slower than the aforementioned devices if speed is critical. The ONE Series is available as a transmitter only with 4-20 mA HART output.
4. Transmitter+Switch. This represents a hybrid between the functions of a transmitter and a switch. The ONE Series combines two popular pump protection methods in an all-in-one device, with the same adjustability as the electronic switch and self-diagnostics. The relay provides a signal to a PLC or switches directly, while the transmitter output can provide trending data. Additionally, a SIL 2 certified model with an integral safety relay and 4-20 mA output is available.

All options can work on most types of pumps and in most applications. The primary differentiators are speed of response, pump requirements, and price, however the main purpose is the same – to reliably protect the pump and ensure throughput.