Waching daily Jan 2 2019

[Selection of pressure gauges - Bourdon tube or diaphragm]

In industrial measurement technology,

two different types of pressure gauges are used

Bourdon tube pressure gauges and diaphragm pressure gauges.

They have different operating principles and are therefore suitable for different applications.

With Bourdon tube pressure gauges,

the pressure is measured by a Bourdon tube

transmitting pressure directly to the pointer.

Bourdon tube pressure gauges can be used in a variety of applications

and cover the majority of applications.

However, when Bourdon tube pressure gauges reach their limits,

then diaphragm pressure gauges are used.

In diaphragm pressure gauges,

the pressure is transmitted via a wave-shaped diaphragm to a link.

This then transfers the pressure to the movement.

Diaphragm pressure gauges show their strengths, for example,

when measuring low pressures.

Due to the large diaphragm surface,

measuring ranges from 16 millibar are possible.

For a Bourdon tube pressure gauge, on the other hand,

the smallest measuring range is 600 millibar.

Diaphragm pressure gauges offer good protection against overload

since the diaphragm can support itself against the upper flange.

WIKA diaphragm pressure gauges

offer five times the overload protection as standard ones.

Optionally, even much higher overload safeties can be realised.

Diaphragm pressure gauges also have advantages when used with critical media.

The diaphragm element can be coated with a variety of materials

such as PTFE,

gold,

Hastelloy

and many others.

This protects the instrument from aggressive media.

Optionally,

the lower flange can also be lined with special material.

Diaphragm elements with open connecting flange

are also suitable for viscous media.

Due to the large cross-section of the pressure port,

this cannot clog.

The decision for Bourdon tube or diaphragm pressure gauges

thus always depends on the specific application.

Here at WIKA,

we are happy to advise you on the right choice of pressure gauge for your application.