Fluke 2470 User Manual

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2-1 
Chapter 2 
General Piston Pressure Gauge 
Considerations 
Types of Piston Pressure Gauges 
The piston pressure gauge is sometimes regarded as an absolute instrument because of 
the principle by which it measures pressure. An absolute instrument is defined here as 
one capable of measuring a quantity in the fundamental units of mass, length, time, etc.  
It may be suggested that only certain types of piston pressure gauges qualify in this 
category. 
Figures 2-1, 2-2, and 2-3 illustrate the three most common types of cylinder arrangements. 
A
PR E S S UR E IN
 
glg01.eps 
Figure 2-1. Simple Cylinder 
B
PR E S S UR E IN
 
glg44.eps 
Figure 2-2. Re-Entrant Cylinder