EMERGENCY CYLINDER LOWERING CIRCUIT WITH REGENERATIVE HYDRAULICS AND BURST PROTECTION

摘要

A safety system for bypassing counter balance valves of a catwalk hydraulic cylinder from a remote location in a safe and controlled manner. Oil from a base end of the hydraulic cylinder is routed around the counter balance valves and flows through a velocity fuse to a needle valve, a check valve, and a pump outlet.

主权项

1. A safety valve assembly for controlling hydraulic pressure in a hydraulic cylinder that is used to raise and lower a catwalk, comprising:
a relief valve coupled to a housing and configured to control fluid flow from the housing to a hydraulic tank; a check valve coupled to the housing and configured to control fluid flow from a pump connection of the housing to a rod end connection of the housing; and a needle valve coupled to the housing and configured to control fluid flow from a cap end connection of the housing to the rod end connection.