Dead Weight Tester – Primary Standard

Harwood’s Free Piston Dead Weight Testers

The characteristic extreme sensitivity, repeatability, and accuracy of Harwood’s dead weight tester results from the minute clearance maintained between the piston and cylinder by means of a variable jacket pressure on the outside of the cylinder producing the close fit of a few millionths of an inch clearance – still with fully free sensitivity and exceptionally small leakage.

 

Harwood’s primary standards are self-calibrating, have a controllable long float, and have sensitivity better than one part in three million.  The overall performance results from a simple evaluation of the effective area, allowing determination of the magnitude of the measured pressure with an accuracy of 0.02% of reading. Refer to the Articles section for literature about our dead weight testers.

 

Harwood offer two types of deadweight testers; Large floor models for use with the higher pressures, and small bench models for lower pressures.  There are 6 floor models and 6 bench models – each differ in weight but operate essentially the same.  Models are available in English and Metric units.  Each dead weight tester model has a variety of interchangeable piston and cylinder assemblies to allow for a choice of maximum pressures depending on the area of the piston, while keeping the weight stack the same.

 

The DWT-1000 and DWT-100 are two units we keep in our calibration lab and use as our primary calibration devices. See our calibration services pages for all of our in-house calibration offerings.


Floor Model Primary Standards to 200,000 psi

The DTW-1000 is a system capable of producing incredibly accurate measurements anywhere within the domain of 0 – 200,000 psi. The main components are the control panel and the weight stack. The control panel is essentially a combination of two separate systems- the measured pressure system, and the jacket (auxiliary) pressure system. Having the controls for both systems on one panel makes it easy and convenient for the operator to manipulate the device without assistance. Other models are available with metric units and a variety of maximum pressure ratings.

 

For details on all of our floor model primary standard deadweight testers, click the following link:  Floor Model Primary Standards

 

Manganin Cell Calibration with DWT-1000 Dead Weight TesterSystem Features:

  • Convenient panel smoothly operates the powered loading and unloading of heavy weights
  • Measured pressure and jacket pressure gages and digital indicators

 

Ports:

  • Female high pressure 12H-1 ports (3/4″-16 threads)
  • Other porting can be provided

Weights:

  • Austenitic stainless steel
  • Insensitive to earth’s magnetic field
  • Noncorroding
  • Machined to ± 0.01%

Certain petroleum distillate fluids are required for 200,000 psi service. At lower pressure service, other fluids may be used.


Bench Model Primary Standards to 20,000 psi

The DWT-100 is Harwood’s main bench model for primary pressure standards within the domain of 0 – 20,000 psi. All of our bench models have the same necessary components as the larger models. Jacket pressure and measured pressure  controls are built into the small console making for simple operation. Other models are available with metric units and a variety of maximum pressure ratings.

 

For details on all of our bench model primary standard dead weight testers, click the following link:  Bench Model Primary Standards

 

Console Features:DTW-50 Dead Weight Tester

  • Convenient storage stack
  • Jacket and measured pressure gages
  • Built-in, fine adjusting screw pump
  • A wide choice of fluid, from tap water (special) to oil, may be used

Ports:

  • Female high pressure 4L ports (9/16″-18 threads)
  • Other porting can be provided

Weights:

  • Austenitic stainless steel
  • Insensitive to earth’s magnetic field
  • Noncorroding
  • Machined to ± 0.01% of nominal

 

Contact the high pressure component experts at Harwood Engineering today for more information about the primary standard components available for a range of industrial applications.