Harwood Engineering Company is well experienced when it comes to pressure standards for extreme high pressures, with a familiarity spanning several decades devoted to research, and having developed its own unique primary and secondary pressure measurement devices. Harwood is pleased to offer a product line of primary standard “controlled-clearance” deadweight testers, as well as two types of secondary standard devices; the Manganin® Cell and the Strain Gauged Cell. We also offer a secondary standard device for dynamic pressure gauge calibration up to 150,000 psi.
Harwood invented the controlled clearance dead weight tester as a primary standard for pressure measurement in 1949, and it’s still at the forefront of the industry to this day. Harwood’s controlled clearance dead weight testers are free-piston gauges that have unparalleled precision and ease of use at pressures higher than any other primary standard device on the market. We offer bench models for pressures to 20,000 psi and larger floor models for pressures up to 200,000 psi and higher. Metric units are also available.
Harwood Engineering uses both Manganin® Cells and Strain Gauged Cells as secondary standards for pressure measurement. The Manganin® cell has significantly greater accuracy, although it is more delicate than it’s counterpart. The Strain Gauged Cell – designed specifically for rough service – is extremely reliable and durable. We recommend the Strain Gauged Cell for most applications, unless the extra accuracy is necessary- such as in a calibration laboratory.
The positive step-pressure generator is a device used to calibrate dynamic gauges ranging from as high as 0 – 150,000 psi to as small as 0 – 5,000 psi, with a surge time of approximately 0.2 milliseconds. The device is fed from a liquid pressure generating system- typically our 200,000 psi Air Operated Panel. Data acquisition equipment can be used to measure surge time and pressure readings.