Coliter ® Standard Fully Welded Steel Ball Valve – Zero External Leakage for High-Capacity Buried Pipelines
Standard Fully Welded Steel Ball Valve – PN25, DN125–600, Monoblock Carbon Steel Body for Urban Heating, Natural Gas & Industrial Mainlines
The Coliter® Standard Fully Welded Steel Ball Valve (Model: PN25, DN125–600) is a robust, maintenance-free isolation solution designed for large-diameter buried pipelines in urban centralized heating networks, natural gas transmission mains, pressure regulating stations, and industrial fluid systems. Constructed from high-strength carbon steel seamless pipes, the valve body is formed through precision pressing and fully welded using advanced automated welding processes—creating a monolithic, leak-proof structure with no external joints or potential failure points. Rated at PN25 (2.5 MPa), it operates reliably across a temperature range of -40°C to 200°C, enabled by a dual-sealing system featuring carbon-fiber reinforced PTFE rings and resilient gaskets that ensure zero leakage over tens of thousands of cycles. The internal stainless steel ball (304/316) is supported by a rational bearing structure for smooth, low-torque operation even at full differential pressure. Designed for direct burial, it eliminates the need for traditional valve chambers—reducing civil works costs and enabling ground-level operation via extended stems or gear actuators. Available with butt-weld, flanged, or threaded end connections, and optional features such as grease injection ports, venting devices, and anti-static protection, this valve meets stringent safety and durability requirements for critical infrastructure. With a service life exceeding 15–20 years, it represents a cost-effective, long-term solution for high-capacity pipeline isolation.
Installation diagram
Product Description
| DN | Nominal diameter | DH | d | t | L | H1 | H2 | A |
| A/B | ||||||||
| 50 | 40 | 89 | 60.3/57 | 4 | 300 | 35 | 135 | 180 |
| 65 | 50 | 108 | 76.1/76 | 4 | 300 | 35 | 144 | 275 |
| 80 | 65 | 133 | 88.9/89 | 5 | 300 | 44 | 154 | 275 |
| 100 | 80 | 159 | 114.6/108 | 5 | 325 | 50 | 193 | 385 |
| 125 | 100 | 193 | 139.7/133 | 5 | 325 | 62 | 218 | 365 |
| 150 | 125 | 219 | 168.3/159 | 6 | 350 | 83 | 343 | 650 |
| 200 | 150 | 273 | 219/219 | 7 | 400 | 84 | 345 | 800 |
The end welding of all steel ball valves adopts electric welding or manual welding. Valve chamber overheating should be avoided. The distance between the welding ends should not be too short to ensure that the heat generated during the welding process does not damage the sealing material. During the installation process, all valves should be opened.
Structural characteristics
- The valve body is formed by pressing seamless steel pipes.
- The overall structure of the valve adopts a fully welded manufacturing process to reduce external leakage; The weight of the valve is greatly reduced and installation is more convenient.
- Adopting single sex gaskets and carbon fiber reinforced sealing rings, it can withstand tens of thousands of reciprocating movements without leakage, ensuring the service life of the valve.
- The sealing of the valve can be used continuously at -40 °C -200 °C without failure.
- The connection methods include butt welding, flange, threaded connection, and other forms. The opening adopts methods such as handle, turbine drive, and electric drive.
- Long rod direct buried welding ball valves can be deeply buried underground, without the need for valve wells. The operator only needs to operate on the ground with a handle or turbine transmission mechanism, which is very convenient.
- Fully welded ball valves are widely used in urban centralized heating, natural gas transmission pipelines, pressure regulating stations, and other fields. It is the preferred valve for engineering.
Characteristics of fully welded valves
- Leading technology domestically, maintenance free, and long service life.
- The welding process is unique, with no pores or sand holes, high pressure resistance, and zero leakage of the valve body.
- Adopting high-quality stainless steel balls and a double-layer supporting sealing structure, the ball support material is reasonable.
- The sealing gasket is made of materials such as Teflon, nickel, graphite, and has undergone carbonization treatment.
- The valve well has low cost and convenient opening operation.
- The length of the directly buried welded ball valve body can be determined based on the burial depth dimension.
- Equipped with a non return valve type grease injection port that can prevent backflow of lubricating sealant under high pressure.
- According to the individual needs of the pipeline system, valves are equipped with devices for release, discharge, and prevention.
- CNC production equipment, strong technical support, and reasonable combination of software and hardware.
Product Inquiry
We will contact you within one working day. Please pay attention to your email.
Faq - Frequent questions
Introduction to Fully welded ball valve
Coliter®’s three-way ball valves enable precise flow direction control, mixing, or isolation in HVAC, process, and industrial fluid systems. The series includes the Q44F L-port (90°) three-way ball valve for switching flow between two outlets, and the Q45F T-port (straight-through) type for mixing or diverting flows from a common line. Available in manual (Q44F/Q45F), gear-operated (Q344F/Q345F), pneumatic (Q644F/Q645F), and electric (Q944F/Q945F) actuation, these valves feature forged brass, carbon steel, or stainless steel (304/316) bodies with PTFE or reinforced soft seats for bubble-tight shut-off (ISO 5208 Class VI). Rated at PN16 (1.6 MPa) and suitable for temperatures up to 180°C, they offer low torque, full-port flow, and reliable operation—ideal for chiller bypass, heat exchanger control, and dual-circuit distribution.
