Dual piston deadweight testers can greatly enhance a lab?s ability to calibrate wide pressure ranges with the best accuracy. With Distrustful and devices under test (DUTs) that have a wide measuring range, calibration can be a lengthy process, as you must change pistons in between test points as a way 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 find a solution for industry needs.
Formula for pressure calculations
Because 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 need to be calibrated against instruments of a higher amount of accuracy. Deadweight testers (generally known as pressure balances) are high accuracy instruments used 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 as a way to generate the average person test points in a calibration.
The mass load is proportional to the prospective pressure, which is achieved through optimally graduated masses. The look of the entire calibration system, along with 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.
A deadweight tester typically consists of a single piston-cylinder system. This requires mass sets to be changed to be able to calibrate multiple or wide measuring ranges. This could become a cumbersome process, one which requires many resources. In 1953, the entity today referred to as DH-Budenberg pioneered the initial 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 (ruthless) pistons housed in one unit. Utilizing a single mass-set it had been now possible to generate two points of equilibrium at 55 bar (low pressure) and 550 bar (high pressure) respectively. This is followed with the release of ruthless variant which could generate pressure upto 1100 bar.
Explanation dual piston design
The first dual piston design was largely made of tool roll, and had an accuracy of 0.03 % of the pressure being measured in the typical model and 0.05 % in the ruthless model. In dual piston calibration, the strain on the low pressure piston is transferred to the auxiliary piston, which is directly connected to the weight carrier. When correct pressure is obtained, the piston head skirt floats within the reduced range or ?blue band.? To reach high pressure, the pressure is increased and the low pressure piston rises until a knife-edge on the bottom flange makes a seal against the low pressure cylinder and acts because 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 now 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 DH-Budenberg? Sick And Tired , the premier deadweight tester for industrial applications. It really is especially useful for calibrating a transducer with a wide measuring range, while maintaining the high accuracy for testing and calibration. By using just a single mass set and calibrating instrument, this technique 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 can be found on the WIKA website.