Ultramatic Pump Selector Valve Operation

Posted by kunzea On 2022/5/27 11:30:40

I'm wondering how this valve operates. What I don't understand is how the valve operates with only one oil inlet. Does the rear pump simply OVERWHELM the inner spring and the first exhaust port thus moving the valve to engage the outer spring? At this position fluid is routed to the front pump relief valve which idles the front pump. Pressure greater than 93 PSIG exits the front pump exhaust port achieving regulation at 93. What is the purpose of the first annular groove?

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  Ultramatic Pump Selector Valve.png (318.76 KB)