Product Introduction

Derived from simple cock valves, a plug valve is equipped with a conical or cylindrical rotatable plug. Rotating the plug changes the alignment between plug passage and body port to realize flow regulation. It consists of few parts with compact structure and fast operation; only a 90° rotation switches between full open and full closed. Smooth internal bore without abrupt section change brings minimum pressure loss.

One prominent advantage is easy multi-port configuration. A single plug valve can be designed into two-way, three-way or four-way ports, simplifying pipeline layout and cutting down auxiliary valves and pipe fittings.

Main Advantages

1. Suitable for frequent operation with quick and labor-saving opening & closing.

2. Low flow resistance.

3. Simple structure, small dimension and light weight for convenient maintenance.

1. Excellent sealing performance.

2. Free from installation direction restriction; medium can flow bidirectionally.

3. Vibration-free and low noise during service.

4. Structurally classified into four types: compression plug valve, self-sealing plug valve, packing plug valve and lubricated plug valve; by flow passage: straight, three-way and four-way.

Structural Features

Plug valve features compact size and flexible 90° rotary operation of stem. Straight type maintains full bore without flow shrinkage for minimal flow resistance, while three-way/four-way versions serve for flow diversion and switching. Compact design lowers cost, yet sealing face tends to wear easily, requiring larger operating torque and shortening service life.

Classification

1. By Structure

Double-seated lift plug valve: Soft seal construction with double block & bleed function and pressure balance device to avoid abnormal pressure surge and reduce operating friction.Metal seated lift plug valve: Bidirectional sealing seats, unrestricted by medium flow direction.Compression plug valve: Sealing realized by tightening nuts to compress plug against body; low cost but inferior sealing for low pressure & small bore.Self-sealing plug valve: Medium pressure pushes plug tightly for self-enhanced sealing as working pressure rises.Lubricated plug valve: Grease injected between plug and body to form oil film seal; reliable for high temp, high pressure and corrosive service.Lift plug valve: Available in soft/metal seal. Plug lifts first before 90° rotation to cut sealing friction when opening; descends after rotation to form tight seal upon closure.

2. By Flow Passage

Straight plug valve: Inlet and outlet in straight line, low resistance for general service.Three-way plug valve: Three ports for flow splitting, combining or direction switching, widely used in petrochemical industry.Four-way plug valve: Four ports for complex fluid switching control.

3. By Seal Material

Soft-seat plug valve: Rubber/plastic sealing for low pressure, ambient temperature and corrosive media.Metal-seat plug valve: Metal/ceramic sealing for high pressure, high temperature and abrasive medium working conditions.