PRESSURE BALANCED HYDRAULIC DEVICE AND METHOD

摘要

A hydraulic device includes a hydraulic pump, valve stack, interface tube, and upper and lower seals. The valve stack has a pressure balanced connecting with an interface tube receiving bore. The interface tube conveys a hydraulic fluid from the hydraulic pump to the valve stack and has an axial bore open at a first end and closed at a second end with an outlet proximal to the second end. The upper seal seals the interface tube in the interface tube receiving bore and is disposed annularly about the interface tube between the outlet and the second end. The lower seal seals the interface tube in the interface tube receiving bore and is disposed annularly about the interface tube proximal to the outlet and between the outlet and the first end. The upper seal and the lower seal balance a pressure of the hydraulic fluid from the outlet.