3.The Role of Checking Oil Leak Flow in the Housing
When a pump or motor gets worn out or damaged, it leaks more internally, which means less oil is available to do the work. You can check the pump or motor's condition by measuring the flow of oil coming from the housing leak line (which shows internal leakage) and comparing it to the expected flow. This tells you how much wear or damage has happened.
In open-loop systems, it's common to monitor the housing pressure and leakage of pumps or motors. Sometimes, if the equipment isn't working properly and the hydraulic pump is thought to be the cause, operators might remove the pressure plug to let the oil spray out. By looking at how high and fast the oil sprays, they try to judge if the pump's leakage is too high, which could mean it's too worn. However, this is risky and wastes oil, so it's not a good idea. A better way is to use a flowmeter to check the actual flow.
4. Closed-Loop Housing Oil Leakage – What You Need to Know
When testing the flow in a hydrostatic drive system, you also need to think about the flow from the make-up oil pump. In most closed-loop systems, the relief valve on the make-up oil pump releases oil into the pump or motor housing. Some customers route the return oil from the pump and motor separately to the oil tank, while others send both back to the tank together.
In our case, if the customer connects the hydraulic motor's housing oil return line to the pump housing, and the oil flows back to the tank through the pump housing, the flowmeter in the pump housing oil return line should show a flow that is about the same as the flow from the make-up oil pump. Here's why: Let's say the make-up oil pump has a flow rate of 11 L/min. Out of that, 4 L/min leaks through the motor housing (internal leakage), and 3 L/min leaks through the pump housing. So what happens to the remaining 4 L/min? It has to go somewhere-it can't just disappear. That's when the relief valve on the make-up oil pump kicks in and lets the remaining 4 L/min flow out. But it still ends up back in the pump or motor housing based on how the relief valve is set up.
So, if the motor's housing oil return is going through the pump housing and back to the oil tank, the flowmeter in the pump housing oil return line should show the total of those three flows (11 L/min). This would be normal. If the flow is different, it might mean the pump is leaking too much oil.
