Dual piston deadweight testers can greatly enhance a lab? Grounded to calibrate wide pressure ranges with the highest accuracy. With transducers and devices under test (DUTs) that have a broad measuring range, calibration could be a lengthy process, as you must change pistons in between test points so as to calibrate its entire range.
However, a dual piston deadweight tester has a higher range piston and low range piston, which allows the technician more flexibility and efficiency when it comes to calibration. This advancement originates from decades of innovation and customer interaction to locate a solution for industry needs.
Formula for pressure calculations
Since the Industrial Revolution, high accuracy pressure measurement is a key requirement in process industries. Pressure measuring instruments like gauges were employed to measure and monitor pressure conditons. They must be calibrated against instruments of an increased degree of accuracy. Deadweight testers (also referred to as pressure balances) are high accuracy instruments found in the calibration of electronic or mechanical pressure instruments. The core element of a deadweight tester is a precisely manufactured piston-cylinder system, onto which a mass load is applied in order to generate the individual test points in a calibration.
The mass load is proportional to the mark pressure, which is achieved through optimally graduated masses. The design of the entire calibration system, and also the precise manufacturing of the piston and cylinder, ensure quality performance with long free-rotation time and low sink rates of the piston. With measurement uncertainties down to 0.002% of reading, deadweight testers are the golden standard in calibration.
Unforgettable consists of a single piston-cylinder system. This involves mass sets to be changed in order to calibrate multiple or wide measuring ranges. This may turn into a cumbersome process, one that requires many resources. In 1953, the entity today known as DH-Budenberg pioneered the first dual range piston-cylinder technology with two pistons housed concentrically in a single unit. DH-Budenberg was later acquired by WIKA in 2011. The first design included 1/8 in2 (low pressure) and 1/180 in2 (high pressure) pistons housed in one unit. Utilizing a single mass-set it was now possible to generate two points of equilibrium at 55 bar (low pressure) and 550 bar (ruthless) respectively. This was followed with the release of ruthless variant that could generate pressure upto 1100 bar.
Explanation dual piston design
The initial dual piston design was largely constructed of tool roll, and had an accuracy of 0.03 % of the pressure being measured in the standard model and 0.05 % in the ruthless model. In dual piston calibration, the strain on the reduced pressure piston is used in the auxiliary piston, that is directly connected to the weight carrier. When correct pressure is obtained, the piston head skirt floats within the low range or ?blue band.? To attain high pressure, the pressure is increased and the reduced pressure piston rises until a knife-edge on the bottom flange makes a seal contrary to the low pressure cylinder and acts as the high pressure cylinder. Because the low pressure piston will not contribute to the entire weight of the piston and weight carrier, the weight carrier accumulates the auxiliary weight to pay. When correct pressure is achieved, the piston head skirt floats within the high range or ?red band.?
This iconic, patented DH-Budenberg red and blue band piston-cylinder system was re-engineered later with both piston and cylinder components made of tungsten carbide. With the refinements in pressure generation and piston manufacturing processes, dual ranges are actually available around 1,400 bar with accuracies right down to 0.006 % of reading.
These developments in dual piston technology made deadweight testers, such as for example DH-Budenberg?s CPB5800 Hydraulic Pressure Balance, the premier deadweight tester for industrial applications. It really is especially ideal for calibrating a transducer with a broad measuring range, while maintaining the high accuracy for testing and calibration. By using just a single mass set and calibrating instrument, this system can automatically switch between multiple test points of high and low pressure, making pressure calibration seamless, efficient and economical.
Note
More info on our pressure balances are available on the WIKA website.