Precision tubes and precision bellows with special dimensional accuracy


Precision bellows of Bronze as thermal actuator for thermostatic valves

Precision bellows of Bronze as thermal actuator for thermostatic valves


In our precision bellows manufacturing site, located in Poland, as a first step we make deep-drawn precision tubes. Mera Bellows is specialized in the production of very thin-walled tubing with closed ends that is then hydroformed into the typical corrugated shape. Our smallest bellows start at 4.2mm ID and less than 0.1mm of wall-thickness if needed. For designing considerations, the application is of paramount importance. Is the bellows e.g. used as coupling for rotating shafts, as metallic sealing or pressure sensor?

Key parameters:

– lifecycle expectancy
– maximum compression and extension (stroke) that the metallic bellows has to perform
– pressure differentials: between inside and outside of the precision bellows
– working-/max. pressure
– spring rate (N/mm): amount of force that is needed to flex the bellows
– working-/max. temperature
– surrounding media
– geometric limitations

The prior aspects have to be considered by the manufacturer to finally supply a suitable and sustainable component. As part of our zero-failure philosophy, every production process is monitored and statistically analyzed. Mera Bellows applies a 100% final control, visually and for leakage. Spring rate testing, cycle testing and other measurements on demand.

It is crucial to select the right material for your precision bellows


Stainless steel precision bellows for pressure switch applications

Stainless steel precision bellows for pressure switch applications

Different materials are suitable for the production of our precision tubes, including different kinds of stainless steel, brass and alloys of nickel-copper (Monel400) or beryllium-copper. Offering seamless constructions, we can achieve small tolerances in diameter and wall thickness. That helps us to guarantee a stable performance for all our precision bellows. Based on their small spring rates, precision bellows made of non-ferrous metals (especially tombac and bronze) are especially suitable for measuring, controlling and regulating applications. Often in bottom design (one closed end) they are used to convert pressure into movement. In thermostatic heads, for instance, our closed-ended bronze bellows are used millionfold for heating systems all around the world. The thermostat bellows behave like a spring. They are filled with alcohol and actuate the mechanical system. If the temperature rises, the precision bellows expands in an axial direction. The thermostatic valve flow is reduced for an exact temperature regulation. If room temperature decreases, the bellows shortens – and consequently, the regulator valve opens and heating capacity increases again.

Our stainless steel precision tubes are requested to withstand extreme environments and high working pressures. They can be implemented for the distribution of very hot liquids. The corrugated precision metal bellows, manufactured in one of our standard stainless steels are often implemented as flexible maintenance-free hermetic sealing of a valve stem. Other projects require high electric conductivity or extra flexible constructions. For all purposes, we manufacture products that meet your exact specifications.


More applications of precision tubes and precision bellows


– stainless steel thin wall tubes as connecting elements or housings
– hydro- formed precision bellows as core elements of pressure switches
– precision metal bellows for oxygen masks, -controlling the valve opening as they expand and contract with altitude
– stainless steel precision bellows for vacuum valves or vacuum interrupters