How to Braze Your CPV Tube Fittings

Important Installation Requirements for CPV Tube Fittings

The O-ring is the sealing component in CPV tube fittings. To seal, this O-ring must be completely surrounded by metal. Therefore, the FLAT FACES on the body and tailpiece MUST BE IN COMPLETE CONTACT upon installation.

If there is any space between the fitting faces-due to misalignment or insufficient tightening-the O-ring may blow out or extrude through the gap. 0-ring failure is due to improper installation and will cause leakage.

Proper installation will assure a leaktight connection. At our valve manufacturing company we want to help you and your CPV tube fittings do the best job possible. If there are any questions about installation procedures, please contact CPV.

Mark VIII® Fittings

Mark VIII® fittings from CPV. Always a perfect match with your system.

The design of Mark VIII® fittings assures leakproof connections in gases or liquids up to 6000 psi. The union connections in this system are flat faced with a resilient O-ring incorporated into a close tolerance groove on one side of the body. Low torquing of the union nut compresses the O-ring to seal the connection.

These fittings make it easier, faster and more economical to change out gauges or other components that require regular replacement. They are available in couplings, tees, elbows, crosses and reducers in sizes from 1/4 to 2 OD. CPV also offers a complete system of valves (shutoff & needle) to compliment the Mark VIII® fittings.

Mark VIII® fittings can be heat sealed into a system by welding, orbital welding or brazing. Brazing can be done with elementary tools and requires very little training. The test data and photos to the right demonstrate the durability of Mark VIII® Fittings when they are brazed to brass, copper, steel and stainless steel tubing with a hand held propane torch. Each tubing section was hand-tight assembled on the end of a hydraulic pump before pressurization.

In every case the tubing failed before the Mark VIII® Fittings. In fact, the burst pressures of 9,000 to 16,000 psi substantially exceeded the 6000 psi rated pressure of these Mark VIII® Fittings.

CPV has been a leading manufacturer of valves and fittings since 1915. The company’s innovative designs are well suited to standard applications, as well as one-of-a-kind custom requirements.


O-Ring Straight Thread Boss SAE J1926/1

Used in Cat. 64T and Cat. H864T female straight thread boss fittings