Understanding Pump Stations
Many times people can feel overwhelmed by the information and terms of a new product or area is unfamiliar to them. This is not uncommon! Technical and sales people tend to bring terms into their presentations that are foreign to the average person.
Pumptronics doesn’t believe in inundating people with technical jargon. However, we understand that some people may want to become more familiar with the terms and wording commonly used to describe our products in order to get a better understanding of how they work or function – hence our simplified glossary of terms.
Glossary – In order of most commonly used words
Pump Station – a combination of pumps and electrical control equipment prefabricated on a mounting plate (skid), with piping, valves and sensors to transfer fluid (generally water) from one point to another.
A. Methods of Operation
- Variable Speed Electric
- Constant Speed Electric
- Engine Drive
B. Pump Styles
Any combination of “A” and “B” except “engine drive” – “submersible”, can become a pump station.
Pump – since this is a common generic word we will describe the most common types of pumps used for water movement, but they can be applied to other industries and fluids as well. All four of these types of pump can be used to build a pump station.
Turbine Pump – also known as lineshaft turbine, generally pumps from a vertical well. The main components are bowl assembly and impellers (actual pump), the discharge head (turns the water from a vertical direction to a horizontal direction and holds the motor), the motor, the column (connects the bowl assembly to the discharge head) and the shaft (connects the impellers inside the bowl assembly to the motor).
Submersible Pump – also known as submersible turbine, pumps from a vertical well also. The main components are bowl assembly and impellers (same as above) and the motor. The submersible motor is connected directly to the impellers at the bottom of the bowl assembly, unlike the turbine pump that uses shafts, bearings and discharge head. The submersible pump does not have to be installed vertically like the lineshaft turbine does. This pump can be installed at any angle between 5 degrees and 90 degrees.
Centrifugal Pump – can pump from pond, stream or anywhere a suction line can be installed, including a vertical well like the previous pumps. The main components are the impeller (including pump casting) and the motor.
Diesel Pump – can be a turbine pump or a centrifugal pump since the term diesel only describes the engine and not the style of pump. The most common is a centrifugal pump (without the electric motor). A right angle drive and lineshaft turbine can also be installed on the diesel engine, however at a greatly increased cost.
Diesel Engine - The motor that drives the pump - in this case an engine using diesel fuel.
Murphy Package- Automated Control Panel used to run diesel engines is similar to variable speed pump stations.
Drive – this is an abbreviated term to describe a main component on the variable speed pump station. The drive changes the speed of the motor and thus gives us the term “variable speed”. Other common terms in the technical field are inverter, frequency drive, and frequency modulator. The drive is a big box of capacitors, rectifiers, diodes, transistors, fuses and circuit boards. The combination of these items modifies a 60-hertz electrical signal, and by doing so allows us to change the hertz, voltage and current going to the motor. As a result the motor speed changes. When you change the motor speed, you change the flow and pressure generated by the pump.
Pressure Regulating Valve – (Picture Not Available at this time) The PRV serves the same purpose on a constant speed pump station as a drive serves on a variable speed pump station. Both are intended to keep a constant pressure in the irrigation system. Other common terms (but not accurate) are Clayton Valve or Singer Valve. These are some of the major manufacturers of the valves but they also make many other types, such as, relief valves, reducing valves, and combinations of reducing, regulating, sustaining and check valves.
Other Types of Valves on a Pump Station are:
Butterfly Valves – This valve is used to stop the flow of water through the pipe system. A butterfly valve generally is positioned between two flanges. It has a flat disc inside that seals like the gate in a gate valve. The only difference is that the butterfly turns 90 degrees to stop the flow of water instead of going up and down.
Ball Valves – These valves have a ball inside with a hole in the middle. When the handle is turned the ball turns. There is a double seal on each side of the ball for a positive seal. Many times ball valves are used as an alternative to the gate valve.
Check Valves – are used to stop the back flow of water. There are many types such as swing gate check valves, double door valves and plunger type check valves. Each type has it's place but for irrigation, the best valves are spring loaded.
PLC – in technical terms is a Programmable Logic Controller. We call it the brains of the pump station. Whether you have a constant speed or variable speed pump station, the PLC determines what is to happen when you turn a switch on based on the software information in the controller. The PLC receives information from sensors and switches on the pump station, compares values from these sensors and sends signals to other devices (such as telling the drive to speed up or slow down depending on the pressure reading it receives).
Other parts of the electrical panel will include:
Fuses – Used to protect the electrical system should a short occur between wires.
Disconnect – Just a fancy word for switch, the disconnect shuts power off to the panel.
Transformers – Changes power from one voltage to another.
Contactors – Close to send power to the motors or other electrical apparatus and open to stop power from continuing down the wires.
Overloads – Sense the current going to the motor and will disconnect the contactors if the current to the motor is above the overload setting.
These are the basic terms you will hear most often when talking about pump stations.