Stainless Steel Check Valves Tube to Tube

Threaded pipe connections require PTFE thread tape or liquid sealants. Under pressure and temperature cycles, tape fragments or paste residues can shred and migrate into the process line, clogging sensitive analyzer orifices, chromatograph columns, and solenoid valve seats. In contrast, Tube-to-Tube compression check valves require zero sealants, guaranteeing ultra-clean, contamination-free fluid containment. Additionally, compression connections eliminate the need for separate tube adapters, shorten installation time, and can be repeatedly disconnected and remade without loss of sealing performance.

Pioneer Industries manufactures Tube to Tube check valves in all standard fractional tube sizes: 1/8″, 1/4″, 3/8″, 1/2″, 3/4″, and 1″ OD, as well as metric tube sizes: 3 mm, 6 mm, 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, and 25 mm OD. The internal flow orifice is sized to match tubing bore dimensions, optimizing flow coefficient (Cv) values from 0.18 to 6.56 with minimal forward pressure drop.

Our 316 Stainless Steel Tube-to-Tube check valves are rated for working pressures up to 5,000 PSI CWP (345 Bar) in sizes 1/8″ to 3/4″ (3 mm to 20 mm) and 3,000 PSI CWP (207 Bar) in 1″ (25 mm). The pressure rating matches or exceeds the allowable working pressure of heavy-wall seamless instrumentation tubing per ASME B31.3. Working temperature capability ranges from -45°C to 204°C (-49°F to 400°F) with standard FKM Viton seals, and up to 315°C (600°F) with optional Kalrez FFKM seals.

The valve features a hydrodynamically contoured poppet nose and continuous body guide ribs that keep the poppet precisely centered throughout its travel stroke. The helical spring is held captive in a machined pocket, ensuring uniform compression without buckling. This concentric alignment prevents lateral cocking, eliminates flow-induced chattering under variable flow velocities, and protects the spring from cyclical fatigue failure.

Pioneer Industries offers five standard factory-calibrated spring cracking pressures: 1/3 PSI (0.02 Bar), 1 PSI (0.07 Bar), 5 PSI (0.35 Bar), 10 PSI (0.7 Bar), and 25 PSI (1.75 Bar). Once inlet pressure overcomes the cracking pressure, the poppet lifts progressively, increasing flow area until full stroke is attained. Our comprehensive engineering catalogue provides flow curves showing water and air flow rates versus pressure drop (Delta-P) across each size.

For hydrocarbons, natural gas, synthetic hydraulic fluids, and fuels, Fluorocarbon / Viton (FKM) is the standard recommendation. For compressed air, water, and low-temperature petroleum lines, Nitrile (Buna-N) provides excellent elasticity down to -34°C. For polar solvents, hot water, and steam tracing, EPDM is ideal. For ultra-high purity specialty gases, chlorine, or severe acids, Kalrez (FFKM) provides virtually universal chemical inertness up to 315°C.

To assemble, insert squared and deburred stainless steel tubing into the valve end connection until it bottoms firmly against the internal shoulder. Tighten the nut finger-tight. For sizes 1/4″ through 1″ (6 mm to 25 mm), hold the valve body with a backup wrench and tighten the nut 1-1/4 turns with an open-end wrench. For 1/8″ and 3 mm tubing, tighten 3/4 turn. Before pressurization, use a standard gap inspection gauge between the nut and body shoulder to confirm sufficient pull-up.

Yes. Pioneer Industries double-ferrule tube fittings and check valve tube ends are engineered to strict international dimensional and metallographic tolerances, ensuring 100% component interchangeability and intermixability with major global brands including Swagelok®, Parker A-LOK®, and DOK-LOK®. Contractors can install Pioneer check valves into existing instrument tubing loops without modifying tubing configurations.

Every check valve undergoes 100% factory inspection in Mumbai, including a hydrostatic shell test at 1.5× working pressure and a pneumatic seat test at 1,200 PSI (80 Bar) dry nitrogen to verify zero bubble leakage and exact cracking pressure calibration. Each consignment is shipped with an EN 10204 3.1 Material Test Certificate, PMI verification, and pressure test report. Third-party inspection by agencies like TUV, DNV, Bureau Veritas, or Lloyd's Register is readily arranged.