LR-Cal LDW-H, Руководство по эксплуатации, Страница: 11 / 72

Deadweight Tester / Pressure Balance GB
LR-
Cal
LDW-H
Operating Instructions LR-
Cal
LDW-H 11
2.3.4 How the cross-sectional area responds to pressure .
At higher pressures, the effective cross-sectional surface changes due to the pressure load.
The ratio of the cross-section and prevailing pressure is linear within an initial approximation. It is
represented by the coefficient of expansion caused by pressure distortion (  ).
pressure Nominal 1
pressure Nominal
 


pressure True
Example:
Measuring point: 1000 bar
System with distortion coefficient: 10
–7
1/bar:
bar bar pressure True 90 . 999
1000 10 1 1
1000
7

  


Without the correction, measurements would differ from the nominal applied pressure by 0.01%.
2.4 Arrangement of control elements .
The LR-
Cal
LDW-H instrument bases are available in 2 variants:

Standard hydraulic base LR-
Cal
LDW-H-S
- up to max 1,200 bar / 16,000 psi
- with integrated pressure generation through priming pump and spindle pump
- tubing made of stainless steel (1.4404), 6 x 2 mm
- Standard pressure transmission medium: mineral oil
Optional: Sebacate oil, brake fluid, Skydrol or Fomblin oil

High-pressure hydraulic base LR-
Cal
LDW-H-H
- up to max 1,400 bar / 20,000 psi
- with integrated pressure generation through priming pump and spindle pump
- tubing made of stainless steel (1.4404), 6 x 2 mm
- Pressure transmission medium: mineral oil or Sebacate oil
As a standard both instruments bases are fitted with a connection for the piston-cylinder system with
G3/4 B (male) thread.
The optional quick connector can be installed as an option allowing a quick and safe change of the
piston-cylinder system without the need for tools (not available for the hydraulic high-pressure
version!).
The connection of the test item is made without tools using a quick-connection. Via the freely-rotating
knurled nut, the test item can be oriented as required. As standard, a threaded insert with a G1/2
female thread is provided. Other threaded inserts are available to connect the most common pressure
measuring instruments.