what gas is this? Nr:4

Joseph wrote in news:d72ed770-44f3-4767-a315- snipped-for-privacy@26g2000hsk.googlegroups.com:

What leads you to believe that this is not sensor number 4?

The nearest elements are N Nitrogen Ne Neon Na Sodium (Natrum) Ni Nickel Nb Niobium Nd Neodymium Np Neptunium and... No Nobelium

More likely means "number four" from a European maker?

Brian W

I have no idea, as I don't know its history. I bought it just for the purpose of using a metal obedient hose (retains its shape). But to do that I have to disassemble the hose from the unit and hence this concern.

HOw are pressure sensors implemented? I assume its some kind of gas or fluid inside the system ? By the way the dial is a mechanical dial, like the old time clock. I pressed my finger on the sensor and can see the dial moves in respond to it. Any idea what fluid/gas is inside ? Its not going to make a person blind or cause skin burns or anything like that right?

Mechanical pressure gauges are almost always constructed on the bourdon tube principle - which amounts to an oval section copper tube formed to a stoppered crescent shape. Increasing pressure sent to the inside of this pipe attempts to straighten the curve. This small displacement is magnified with clockwork and applied to a pointer.

The cases of these gages are sometimes filled with oil, in order to damp vibrations which can wear out the teeth on the clockwork.

By contrast, electrical pressure gages use a spring diaphram with a strain gage glued to to it. The SG senses the deflection of the diaphram, which is amplified.

Brian Whatcott Altus OK

A picture is worth a thousand words.