A popular question we are asked is “Why do you need to use an open center hydraulic circuit when driving a submersible pump?” The quick answer is to keep the pump from coming to an abrupt sudden stop.
Let’s think of it in terms of driving a car. You are driving your car and the traffic light turns yellow and then red. You apply the brakes just enough to slow the car to a stop. Imagine what it would be like if you had to slam on the brakes or jam the transmission into ‘Park’ every time you needed to stop. Both you and the car would experience excessive wear and tear. A closed center hydraulic system acts the same way when driving anything with a hydraulic motor, especially driving a pump.
1.) In a closed center circuit, the valve controlling the direction of oil on the submersible is placed in the center (off) position, the oil returning from the submersible pump is blocked and has nowhere to go. The pump impeller goes from spinning fast to an abrupt halt. This can cause damage to the pump and cause motor seal failure.
2.) In an open center circuit, the valve controlling the direction of oil on the submersible pump is allowed to pass through the valve and return to the oil reservoir and allows the pump impeller to slowly wind down. See this link for a hydraulic diagram that shows a typical open center hydraulic circuit.
All of Hydra-Tech’s standard power units are single direction open center systems that provide safe hydraulic power matched to the pumps they drive. If it is impractical to change the existing hydraulic circuit on the power unit or vehicle you are using to drive a submersible pump, there is another solution. The Hydra-Tech Pump can be used between the power source and the submersible pump to prevent sudden stops, wrong rotation or over-speeding and allow you to control the pump output.