Home > Instrumentation Tube Fittings
Types: Twin-Ferrule Compression · 37° Flare · Components: Ferrules · Plugs · Caps · End Closures · Grades: Stainless · Inconel · Monel · Super Duplex · PTFE

Kalpataru Piping Solution is a manufacturer of instrumentation tube fittings for the small bore impulse and process lines, such as twin-ferrule compression fitting, 37-degree flare tube fittings, ferrules, plugs, caps and end closures in stainless steel, Inconel, Monel, super duplex and PTFE. These are the leak-tight connections that bring instrument tubing to gauges, transmitters and analysers and keeping the type and grade correct is the key to a hook-up that will not leak. The tables below will direct you to the proper fitting and grade, if you know them.

The busiest grade lines are the Inconel 600 tube fittings and the stainless range, and every fitting pairs with our instrumentation valves so a complete needle-valve-and-fitting hook-up comes from one supplier in one material. Fittings are gauged and, where required, leak tested before dispatch.

Tube Fitting Types

The type is how the fitting grips and seals the tube.

Type

How it seals

Best for

Twin-ferrule compression

Two ferrules, front seals, back grips, as the nut is tightened

Gas-tight instrument and process tubing, the general standard

Single-ferrule compression

One ferrule that seals and grips

Simpler, lower-cost tubing connections

37-degree flare (JIC)

The tube is flared and clamped against a 37-degree seat

Hydraulic and higher-vibration lines

The 37-degree flare tube fittings are the busiest single line here, used where a flared, reusable connection suits the service.

Fitting Components

Beyond the fittings themselves we supply the individual components: front ferrules and back ferrules as spares, allen key plugs and port plugs, caps and fitting end closures for sealing off a line. Keeping ferrules and plugs to the same grade and series as the fittings is what keeps a joint gauged and leak-tight.

Grades We Supply

The grade is chosen for the service chemistry and pressure.

Grade

Best for

Go to

Stainless 304 / 316

General instrument and process tubing

Stainless tube fittings

Inconel 600 / 625

High temperature and aggressive corrosion

Inconel 600 / 625 tube fittings

Monel 400

Hydrofluoric acid and seawater service

Monel 400 tube fittings

Super duplex

High-chloride and seawater, high strength

Super duplex tube fittings

PTFE / Teflon

Chemically inert, non-metallic lines

PTFE tube fittings

We hold Inconel 625 tube fittings, Monel 400 tube fittings, super duplex tube fittings, stainless steel tube fittings and PTFE instrumentation tube fittings across the fitting range.

Complete the Hook-Up

A tube fitting is one half of an instrument hook-up; the other is the valve. We hold the matching instrumentation valves, needle, ball, manifold and monoflange, in the same grades, so a complete impulse line from the process take-off to the transmitter can be specified in one material with one certificate trail. Ordering the fittings and valves together keeps the hook-up from mixing metals at the joint.

Quality, Testing & Certification

Every fitting is dimensionally gauged to confirm the ferrule and thread, and leak testing is provided where the service requires it. Each order ships with an EN 10204 mill test certificate for the material, heat-number traceable, with positive material identification, NACE MR0175 documentation for sour service and third-party witness through BV, SGS or TUV arranged at order stage. Common stainless fittings ship quickly; higher alloys and PTFE are confirmed on enquiry. Send the type, size, series and grade and the quote comes back with the certification built in.

Instrumentation Tube Fittings: Frequently Asked Questions

Twin-ferrule and single-ferrule compression fittings, 37-degree flare fittings, and the components, front and back ferrules, plugs, caps and end closures, in stainless 304 and 316, Inconel, Monel, super duplex and PTFE. If a type or grade is not listed, ask, because we hold more than the site shows and can source to specification.
It uses two ferrules inside the nut. As the nut is tightened, the front ferrule forms the seal against the fitting body and the back ferrule grips the tube, so the joint is both gas-tight and mechanically held. The two-ferrule design tolerates vibration and repeated make-and-break better than a single ferrule, which is why it is the instrumentation standard.
A 37-degree flare, or JIC, fitting seals by clamping a flared tube end against a 37-degree seat rather than by ferrules. It suits hydraulic lines and higher-vibration service and gives a reusable connection. It is the busiest single fitting line we supply, chosen where a flared joint is preferred over a compression one.
Match it to the tubing and the service. Stainless 304 and 316 cover most instrument and process lines, Inconel handles high temperature and aggressive corrosion, Monel 400 suits hydrofluoric acid and seawater, super duplex takes high-chloride and seawater duty, and PTFE is for chemically inert non-metallic lines. Keep the fitting, ferrules and tube to the same grade.
Yes. Every order ships with an EN 10204 mill test certificate for the fitting material, heat-number traceable, with positive material identification, NACE documentation for sour service and third-party witness inspection available at order stage, plus leak testing where the service requires it.

Refractory Anchors

Other Products

Valves