NPT Threaded Vertical Check Valve in 316 Stainless Steel — PTFE Seal, 1000 psi, up to 180 °C

Cematic's 316 stainless steel NPT threaded vertical check valve allows flow in only one direction and prevents fluid backflow in installations with predominantly vertical flow. Unlike horizontal swing check valves, the vertical design operates with the disc in the same direction as the upward flow.

Therefore, it is the correct choice when the piping is vertical. Additionally, its 1000 WOG (1000 psi) rating positions it among the highest-pressure threaded check valves. Thus, it covers services where 200 psi versions are insufficient.

Its SS316 body with a PTFE Teflon seal also offers high corrosion resistance and durability in aggressive fluids. Consequently, it is suitable for the chemical, petrochemical, water, and energy industries where a compact, threaded, high-pressure check valve is required.

Principle of Operation — Vertical Check Valve

The disc of the vertical check valve moves vertically along the flow axis. When fluid flows upwards in the correct direction, pressure pushes the disc up, opening the passage. When the flow stops, however, the disc falls by gravity and automatically seals the PTFE seat.

This ensures a reliable closure without an additional spring — gravity acts as a natural closing force. This operating principle also makes the vertical valve more effective than the horizontal one when the piping is vertical. In horizontal piping, the swing disc needs lateral gravity to close.

In contrast, in the vertical valve, gravity acts directly on the disc, making the closure faster and more consistent.

Vertical vs. Horizontal Swing — When to Choose Each Type

The selection of the check valve type also depends on the piping orientation and process conditions:

• Vertical check valve (this product): For vertical pipes with upward flow. The disc falls by gravity directly onto the seat, so the closure is reliable regardless of flow velocity. It is also more compact than a swing check valve of the same diameter.
• Horizontal swing check valve: For horizontal pipes, where gravity acts laterally on the disc. The disc swings on an axis, requiring a minimum differential pressure to open. However, it is not the correct choice for vertical pipes where gravity does not act correctly on the disc. See NPT threaded SS316 swing check valve →

1000 psi vs. 200 psi — Selection by Working Pressure

Cematic's catalog of NPT threaded SS316 check valves includes two pressure ratings. The choice between these two ratings also depends directly on the operating pressure:

• 1000 psi — 1000 WOG (this product): For high-pressure systems in the chemical, petrochemical, and energy industries where a 200 psi rating is insufficient. Therefore, it is the standard option for high-pressure process services with NPT threaded connections.
• 200 psi — NPT swing check valve: For moderate-pressure systems where the standard rating is sufficient. Therefore, it is the lower-cost option when the pressure does not exceed 200 psi. However, it is the lower-cost option when the pressure does not exceed 200 psi. See 200 psi NPT swing check valve →

Construction Materials

The body is made of 316 stainless steel (SS316), which is the standard material for services with corrosive fluids. Its molybdenum content also offers greater resistance to chlorides and acids than SS304. The seal is made of PTFE Teflon, which is chemically inert to most industrial fluids.

Therefore, it does not show chemical degradation when in contact with acids, bases, or solvents. The connection is NPT threaded, which is the most widespread piping standard in Mexico and industry in North America. Finally, the 1000 WOG rating ensures that the valve operates safely up to 1000 psi in water, oil, and gas services.

Technical Specifications

Fluid Compatibility

This 316 stainless steel NPT threaded vertical check valve with a PTFE seal is compatible with a wide range of industrial fluids. The main groups are described below:

• Corrosive chemical fluids — PTFE is inert to most acids, bases, and solvents; therefore, SS316 and PTFE together cover the most aggressive chemical fluids in NPT threaded lines
• Potable water and process water — SS316 resists corrosion from chlorides and disinfection agents; also, PTFE does not impart taste or contaminants to water
• Desalination water — SS316 resists saline environments without degradation; in contrast, carbon steel or brass would show accelerated corrosion in such service
• High-pressure fluids up to 1000 psi — the 1000 WOG rating covers most industrial high-pressure process services; additionally, PTFE maintains its sealing integrity across the entire pressure range
• Petrochemical fluids and hydrocarbons — PTFE resists hydrocarbons and fuels; however, for extreme conditions, verify compatibility with Cematic's technical team

Applications of the NPT Threaded Stainless Steel Vertical Check Valve

Chemical Industry

The 316 stainless steel NPT threaded vertical check valve prevents backflow of corrosive or hazardous fluids in vertical piping. SS316 also resists corrosion, and PTFE provides excellent chemical resistance to the medium. Consequently, it ensures a long service life in high-pressure chemical process lines with NPT connections.

Potable Water and Desalination

316 stainless steel also handles potable water and desalination processes without degradation in saline environments. Therefore, it is the correct alternative to brass or iron in systems where water quality requires higher-resistance materials. Additionally, PTFE does not introduce contaminants into the water, thus meeting material requirements for contact with potable water.

Power Plants and Refineries

In power plants and refineries, this valve also protects critical pumps and equipment against flow reversals in vertical piping. The 1000 WOG rating also covers the high-pressure services typical in these plants. Consequently, it contributes to the safety and operational efficiency of the system in the event of emergency shutdowns or pumping equipment failures.

HVAC Systems and High Pressure

In HVAC systems with vertical piping, this valve also prevents reverse flow that could damage equipment and reduce system performance. Furthermore, its 1000 WOG rating makes it suitable for high-pressure systems where lower-rated check valves are insufficient. Therefore, it is a compact and economical solution for equipment protection in high-pressure vertical services.

For the complete range of check valves, see check valves collection →

Technical Data Sheet