FlangeS

DA.MA.AN. operates a specialized mechanical workshop that focuses on machining to produce standard flanges as well as custom parts based on specific drawings.

The qualified technical and production team is capable of meeting any client’s needs.

ANSI FLANGES SHORT INTRODUCTION

The American National Standards Institute (ANSI), a non-profit organisation, has established standards to unify production criteria for various products and services, ensuring that they meet specific standards for characteristics and performance.

There are different types of flanges, which are divided into seven series by ANSI standards based on their pressure rating measured in pounds per square inch (p.s.i.), including: 150, 300, 400, 600, 900, 1500, and 2500 p.s.i.

These series correspond to the PN 10, 16, 25, 40, 64, 100, and 175 Kg/cm2 required by UNI and DIN standards.

More specifically, ANSI standards specify the clear characteristics of flanges up to DN 24″ for nominal pressures of 1500 p.s.i. and up to DN 12″ for nominal pressures of 2500 p.s.i.

How many types of flanges are there?

The following list includes flanges specified by ANSI standards and flanges whose conformity to a particular standard is not standardised but commonly shared by American and European manufacturers.

WELDING NECK FLANGES

Hazardous fluids or pipes exposed to environmental conditions that affect the pipe joint are subject to expansion or other line fluctuations, so welding neck flanges are the right solution. The conical shape of the collar guarantees maximum tightness

SLIP-ON FLANGES

The ideal product is the slip on in areas with low operating requirements and low-pressure ratings. This type of flange allows for fast assembly and cost savings of the line and is also suitable for pipelines with not very precise lengths.

LAP-JOINT FLANGES

When the operating pressure is limited and you need to quickly assemble and disassemble the pipe, lap joint are the right solution. They can be rotated independently of the pipe on which they are mounted and do not create any hole-bolt alignment problems. Lap joint flanges are threaded onto an edged pipe or a socket welded at the end of the pipe.

THREADED FLANGES

This type of flange has limited use in cases where, despite high pressures and temperatures, a welded joint is not required to remain in Service. Threaded flanges, therefore, do not have the problem of welding on alloy steels, but they cannot be used where there is a risk of bending stresses, as these would ruin the threads.

BLIND FLANGES

Blind flanges are useful for closing the end of a pipe or the orifice of a valve. But if the pipe is subject to pressure peaks, it is better to tighten it with weld-on or threaded collar flanges with welded caps.

SOCKET WELDING FLANGES

Socket welding flanges are used instead of slip on flanges when a continuous flow without any step is required in small-diameter pipes and at moderately high operating pressures.

MEASURING FLANGES

Measuring flanges are used in pairs to record flow data at a certain point in the pipeline. A disc with a calibrated bore is placed between the flanges by means of spacer bolts. The flanges have holes for inserting pressure gauges and are closed with threaded plugs according to the ANSI B 2.1 standard.