Fitting type 37° conform fully with standard SAE
Fitting type 37° conform fully with ASME specifica- tion for pipe working pressure
The fittings type 37° are a very safe system for mechanical assembly of stainless steel seamless piping.
The fitting, designed for use with 37° flared pipe, consist of three parts: Fitting body, nut and sleeve.
The flared end of the pipes is held between two cone shaped surfaces: body cone and sleeve.
The seal is simply formed by means of a mechanical operation without any part being deformed.
The sleeve is self-centring with a degree of clearance between the nut and the pipe which ensures the correct alignment between the sleeve flare and the body cone and is therefore used as a ring to hold and support the pipe.
The fitting bursting pressure is far higher than that of the pipe it is connected to.
The same fitting allows the junction as between metric tubes as between fractional inch tubes only with changing of the sleeves as the drawing below.
This exchange is possible following the correspon- dence below:
Metric tube 6 mm – Inch Tube 1/4 Metric tube 8 mm – Inch Tube 5/16 Metric tube 10 mm – Inch Tube 3/8 Metric tube 12 mm – Inch Tube 1/2 Metric tube 16 mm – Inch Tube 5/8
Stainless stee fittings are built so that they can operate up to a maximum pressure of 250 bar and tested at a pressure of 375 bar.
To obtain the best self-centring and flare employ stainless steel cold seamless tube in annealed condition.
Verify that the tube is imperfect perpendicularity and concentricity free.
Tubes must be cut square with fine tooting and-saw or with proper device.
Burrs must be removed inside and outside of the tube. Tube end must be clear (inside and outside).
Place the nut and the sleeve on the tube.
Open side of nut and sleeve must be oriented towards tube end.
Flare tube end to form the 37° cone shaped entrance.
Flaring which has been done properly guarantees a longer and more satisfactory life even when subject to critica1 conditions over extended periods.
The maximum outside faring diameter must be same as the outside sleeve diameter, while the minimum diameter must be the same as the sleeve’s maximum inside diameter.
If the pipe flaring is too short, nearly all the fitting’s contact surface will go unutilised.
There is therefore the risk that the pipe surface will be squashed owing to the inadequate contact surface.
In such cases maximum safety against leaks or the flare breaking is not guaranteed.
If the pipe flaring is too long, problems arise with the nut thread which will get jammed and thus prevent the fitting from being assembled properly.
To function most efficiently, the flaring must be perpendicular and concentric with will the pipe and bush.
Imperfect perpendicularity and concentricity could be the result of the pipe being cut incorrectly or an irregular formation caused by the cutting tool or deflective flaring.
How calculate tube length
When the pipe heeds to be cut, a certain length must be taken into account which must then be added to the length of the line.
To establish how long this is, a length “L” representing the part of the fitting cone that enters the flared section of the pipe must be added to the required length of the pipe.
Furthermore, each flaring requires a length of pipe between 0.5 and 1 mm; according to the width of the pipe itself.
Place the sleeve on the flared part
Advance the fitting nut
Adjust the nut manually
Tighten with wrench so as to get a totality enclosed metallmetal joint.
A fundamental feature of the 37” fitting is that it’s easy and quick to assemble. It can in fact be assembled and removed many times obtaining same reliable safe leakproof connection.