723-90-76201 Main Control Valve Pressure Relief Valve PC300-7 PC300-8 PC350-7

Product Specification

723-90-76201 Main Control Valve Pressure Relief Valve PC300-7 PC300-8 PC350-7 PC350-8 PC360 PC390 PC400-7 PC400-8 Excavator Parts

Product Description

The GVO excavator relief valve, compatible with Hitachi excavators, is a key pressure control valve in the hydraulic system. It regulates hydraulic pressure, releases overload pressure, protects core hydraulic components such as the main valve and hydraulic pump, and ensures stable operation of the entire machine.

This relief valve is precision-machined from high-quality steel and undergoes overall quenching treatment. Equipped with oil-resistant and high-pressure-resistant seals, it boasts excellent sealing performance, impact resistance, and wear resistance. Suitable for the high-pressure hydraulic conditions of excavators, it effectively prevents internal leakage, pressure loss, operational instability, and vibration.

Product Introduction

This GVO heavy-duty high-pressure cartridge-type main relief valve is specifically designed for Komatsu's 30-40 ton class large-tonnage mining excavators. It comprehensively covers eight main heavy-duty models: PC300-7, PC300-8, PC350-7, PC350-8, PC360, PC390, PC400-7, and PC400-8. It is the core pressure safety assembly within the machine's multi-way hydraulic main control valve group, undertaking three crucial functions: limiting the maximum pressure of the hydraulic system, providing relief from instantaneous overload under heavy loads, and maintaining pressure under continuous load.

The entire multi-layered sealing and protection system, along with the external mechanical locking structure, is designed to address the  points of 30-40 ton excavators operating in extreme mining environments. It tackles real-world problems such as the aging of mechanical seals in the 7th generation, the high heat load on the 8th generation's electrically controlled sealed engine compartment, severe vibrations and bumps on mining gravel roads, exposure to rain and slurry in the open field, and significant dust intrusion into the hydraulic system. The system features comprehensive reinforcement and upgrades across four dimensions: high-temperature resistance, high-pressure leak-proof sealing, vibration resistance and loosening prevention, and rust and corrosion resistance

The upper valve core reciprocating guide sliding area is equipped with an ultra-high temperature resistant fluororubber combination sealing ring, which can withstand the ultra-high temperature baking of hydraulic oil in the closed engine room in summer, the chemical corrosion of deteriorated hydraulic oil, and the hardening, cracking, and permanent plastic deformation failure of the sealing ring caused by the temperature difference between winter and summer and day and night. The middle section of the valve body is designed with two independent stepped sealing installation grooves, each equipped with a thickened high oil-resistant nitrile rubber O-ring. The double seal superposition forms a closed-loop airtight protection structure, which completely prevents high pressure hydraulic oil from leaking outward from the joint surface between the valve body and the multi-way distribution valve block. Even if the equipment operates continuously under the conditions of long-term heavy load and rushing work in muddy mine pit construction sites, dusty quarries, and poor oil cleanliness due to lagging maintenance of hydraulic oil filter elements, there will be no risk of oil leakage from the outside of the valve body or oil seepage from the thread gaps.

Packaging & Shipping

We use high-strength, environmentally friendly paper export packaging, which is reinforced, cushioned, and moisture-proof, suitable for long-distance international logistics transportation, and meets cross-border freight and environmental protection standards. International transportation adopts formal cross-border logistics, with full tracking of logistics information and supporting customs clearance documents to ensure smooth customs clearance and timely delivery of goods overseas.

Company Introduction

The GVO brand is a manufacturer of hydraulic components. We mainly produce the most comprehensive range of pilot pumps, gear pumps, relief valves, hydraulic pumps, electrical components, hydraulic parts, engine assemblies, traveling assemblies, rotating assemblies, distribution valves, and other components.

We are factory direct sellers without any middlemen profiting from price differences. The quality is definitely the best for you because we are the ones who produce them. We cannot tarnish our reputation. The prices are also the most favorable for you. There is a stable delivery speed.

We value every customer and provide you with the best service. We offer pre-sale, in-sale, and after-sale guarantees. Any problems will definitely be resolved for you. We are always available to serve you.