Pumps are the backbone of numerous industrial processes.
We use pumps today in dozens of industries - oil and gas, wastewater treatment, manufacturing, facilities management, and more - to move millions of gallons of water, crude oil, chemicals, and lubricants. In essence, wherever there are liquids, there are pumps.
Pumps use mechanical energy to pressurize liquids and move them throughout systems. While they are critical to everyday processes, they also consume a lot of energy, which is why pump control and automation are such huge topics right now.
Industrial operators are wondering:
How can we remotely control pumps to improve efficiency, reduce costs, and boost performance?
How can we automate pumps using other information, like tank levels, flow rates, and pressures, to optimize pump operation in real-time?
In this blog, we’ll answer these questions and more. If you’re interested in learning the ins and outs of pump control and automation, you’re in the right place.
What is Pump Control?
Pump control refers to the act of changing how pumps operate using pump controllers and actuators.
For single-speed pumps, pump control means turning pumps on and off. For variable speed pumps, pump control also involves controlling pump speeds. And for all types of pumps, pump control can also include modulating valves to manage the intensity and direction of fluid flow.
Pump control typically involves connecting pump controllers to single-speed or variable speed pump motors
We implement pump control with pump controllers. These devices have logic and inputs/outputs designed specifically for controlling pumps. Furthermore, many pumps come with integrated controllers so operators often don’t have to purchase them separately.
Pump controllers can be “dumb” devices that only store single pump setpoints and actuate accordingly. They can also be “smart” and accept external signals and commands to maintain critical process parameters, like flow rates and pressures. Some pump controllers even have connections to enable remote monitoring and control (we’ll talk more about this in a bit).
How Does Pump Control Work?
Under the hood, what pump controllers really control are the motors or engines that drive pump motion. Whereas pumps convert mechanical power into hydraulic power, motors and engines convert fuel or electricity into mechanical power.
So how you implement pump control depends on the type of pumps you use. Again, the two primary pump types are single-speed pumps and variable speed, or variable frequency, pumps.
Single-speed pumps may have AC- or DC-powered electrical motors. Since these motors operate at only one speed, the pump has a constant output power. However, we can use valves to modulate pressure and flow. The problem with this approach is it may reduce pump efficiency.
In many cases, single-speed pump output rates are controlled using an on/off cycle, called a duty cycle. You can turn pumps on or off over a set period based on the maximum output level of the pump. For instance, if a single-speed pump has a max output of 100 GPD, a pump controller could achieve 20 GPD by turning it on at a 20% duty cycle, for example, 5 seconds on, 25 seconds off. Many chemical injection pumps and metering pumps work this way.
Single-speed pumps can change their output by modulating their duty cycle. A pump with a max output of 100 GPD achieves an output of 20 GPD with a 20% duty cycle, whereas a pump with a max output of 80 GPD achieves an output of 20 GPD with a 25% duty cycle.
Variable speed pumps use a variable speed drive (VSD), also called a variable frequency drive (VFD), for pump control. Variable speed drives modulate the voltage delivered to the pump (for DC-powered pumps) or the frequency of the AC electrical signal supplied to the pump. Here's a great explanation of how AC VFDs work.
DC pumps use pulse-width modulation (PWM) to turn motors on and off rapidly. The underlying basis for control here is the same as with single-speed pumps, but the duty cycle is shortened to milliseconds, and the variable speed motors are designed to handle this modulation.
Why Use Pump Automation?
Whether you have single-speed or variable speed pumps, pump controllers will often accept both user commands or inputs from external sensors. These inputs can modulate pump speed or duty cycle automatically to achieve desired outputs for flow rates and pressures.
This is the best part of remote pump control - automation.
There are three layers of automation when it comes to managing and maintaining pumps: Monitoring, Controlling, and Automating
Pump monitoring involves supervising pump operation to identify performance issues. It does not include any form of control - it’s really all about diagnostics. Pump monitoring is crucial, as it gives your pump a voice to tell you when something is wrong.
Operators can monitor pumps in person or remotely. Many workers will focus their monitoring efforts on pump power supplies or vibration. Though it is possible to monitor pump flow rates and discharge pressures.
Pump control is the actuation layer on top of monitoring. Again, it accounts for when we use digital controllers to change pump characteristics, i.e., speed and on/off state.
So what’s the difference between pump control and pump automation?
Automation takes things a step further. Basic pump control requires someone to manually intervene to change a pump’s parameters. Pump automation is when we incorporate external sensors or processes to change pump outputs automatically.
Pump automation can be achieved by connecting to pump controllers external sensors that monitor pump-related processes. Bonus points for using wireless sensors!
Here are a few examples of pump automation in the real world:
A chemical pump controller maintains a precise concentration of chemical injected based on readings from a water flow meter, even as flow rates fluctuate.
A frac pump uses VFD and pressure reading inputs to maintain a constant pressure for hydraulic stimulation of oil and gas wells.
Beyond these examples, there are countless other ways automation improves pump control.
New Pump Controller Technology
One important note about automation: Until recently, the external inputs that drive automation have typically been connected locally, on location. The sensors that actuated changes were frequently wired directly into pump controllers. But the needs of modern operators are changing. Locally initiated automation is no longer enough. What if we want to control pumps from further away based on different variables? For example:
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