Features and Specifications

• Liquid Lubricated Gas Operated

• Unit: kgf/cm²

• Pressure Range: 1 to 70 kgf/cm²

• Pressure Range Standard Increment: 0.1 kgf/cm²

• Accuracy: +/- 0.015% of reading (+/- 0.008% optional)

• Mass and PCU Materials of Construction:

  Piston material: Tungsten carbide

  Cylinder material: Martensitic steel

  Coefficient of expansion: 16.5 ppm/ Celsius

• Operating Fluid: 55-655 mineral oil

Highlights

• Piston-cylinder design provides stability and repeatability

• Piston flotation indicator

• Screw press for fine pressure control

• Mounted spirit level and adjustable feet

• Test station design with O-rings eliminates the need for PTFE tape or wrenches

• No Fine Inc. weights are available for this model

P3031-KGCM2 Overview

The P3031 models are equipped with a piston/cylinder assembly that is lubricated with oil. This feature makes the device less prone to performance problems that could arise from contamination of the gas supply or the operating environment.

The gas supply is directed into the piston/cylinder chamber through the controls of the deadweight tester. The gas interacts directly with the oil surface, resulting in a rate-less pressure transfer within the system.

The design of the instrument safeguards against accidental overfilling of the chamber, thereby preventing contamination of the gas system. Since there is no physical separation between the gas and oil, there is a possibility of "oil-mist" transfer. Consequently, the standard version is not recommended for use with oxygen. However, a special version of these instruments, which uses a fluid compatible with oxygen, is available.

Operating Principle of a DWT

As the primary standard for pressure measurement, DWTs employ a well-established Piston-Gauge system. This system comprises a vertically positioned, precision-lapped Piston and Cylinder assembly. Accurately calibrated weight masses are loaded onto the piston, which ascends freely within its cylinder. These weights counterbalance the upward force generated by the system's pressure. Each weight is labeled with the tester's serial number and measures the pressure when placed on a correctly spinning and floating piston. The total pressure measured is the sum of the weights plus the piston weight carrier assembly. When the gas pressure within the system equals the combined downward force of the piston and weights, the piston and weights will float freely, indicating that the system is in equilibrium.

The design of a Piston/Cylinder Unit (PCU) incorporated into a deadweight tester allows for a minimal clearance gap between the piston and cylinder. This gap is necessary to let the gas flow between the components, creating a lubricating film and preventing direct metal contact.

P3000 Series Pneumatic Deadweight Testers

The P3000 Series high-performing gas-operated deadweight testers feature a design to improve accuracy and performance, increase reliability and simplify operation. These deadweight testers can be used to calibrate virtually any pressure sensing device, including transducers, transmitters, gauges or pressure switches.

Instrument Base

There are four basic variations in the pneumatic offering; single pressure, single vacuum, dual vacuum and pressure, and oil-lubricated pneumatically driven high-pressure models. Pressure or vacuum is generated by an external source or an optional built-in hand pump.

Categories of P3000 Models

There are many models in the P3000 product line, so for the purpose of this uncertainty analysis they are categorized as shown below.

*Full model names include variations depending on the nominal unit of measurement and inclusion of a built-in pressure pump.

Built-in Hand Pumps (-P models: indicates built-in pump optional)

Pressure or vacuum is generated by an external source or a hand pump (standard on the lower pressure models). The hand pump option is not available on instruments above 500 psi (3.5 MPa).

• Pressure mode: Max pressure 300 psi (2 MPa)

• Vacuum mode: To 90 % vacuum

Piston/Cylinder Assemblies

The piston/cylinder assembly is the heart of each deadweight tester. They are manufactured from materials that provide stability, durability, and low thermal coefficients and distortion. Fluke's experience and knowledge of piston/cylinder production and calibration ensures the precision and performance required for today’s demanding calibration requirements.

Masses

Standard weight masses are series 3 nonmagnetic austenitic stainless steel. Each mass is marked with the serial number of the instrument  and the nominal pressure value relative to the high- or low-pressure piston, when applicable. Vacuum weights and the optional fractional weights are stainless steel and/or solution heat treated aluminum.

Minimum Standard Weight Increments

• P3012, P3022 Pressure: 1 inH2O, (5 mbar, 0.5 kPa)

• P3013, P3023 Pressure: 2 inH2O, (10 mbar, 1 kPa)

• P3014, P3015, P3025 Pressure: 1 psi, (0.1bar, 10 kPa)

• P3031, P3032: 1 psi, (0.1bar, 10 kPa)

• P3011, P3022, P3023, P3025 Vacuum: 0.2 inHg (10 mbar, 1 kPa)

Gravity

For the P3000 Series Deadweight Testers (DWT), customers have two choices. The deadweight tester can be provided matched to standard gravity (9.80665 m/s2 ) and the customer can utilize software (such as Fluke Calibration PressCal) to account for the acceleration of local gravity. Or, the deadweight tester can be provided matched to the local gravity value supplied by the customer. Gravity varies slightly from one location to another. This has an impact on the nominal pressure increments of a deadweight tester. To overcome this issue, at the time of manufacture Fluke Calibration trims the weights to produce the correct nominal pressures at your location. If unspecified, instruments will be calibrated to standard gravity.

Gas Supply

Gas operated (pneumatic) deadweight testers provide a proven, traceable, clean, and easy way for checking accuracy of pressure gauges and transfer standards. All P3000 instruments are fitted with a 1/4 inch NPT female external supply port for connection to the gas supply source. A compressed gas bottle (nitrogen or dry air) fitted with a pressure regulator is recommended. Ten percent above the maximum pressure is required. A built-in hand pump is available on some models to generate pressures to 300 psi (2 MPa). For vacuum requirements, an external vacuum pump can be connected to the 1/4 inch port. The built-in hand pump will also generate up to 90 % vacuum.

PressCal Software

PressCal software is a Windows-based software program that allows users to easily apply all necessary corrections (e.g. local gravity, temperature, pressure head, etc.) to enhance the deadweight tester performance. Calibration details are then stored and/or used to automatically create a calibration certificate. The use of PressCal allows for an improved accuracy of 0.008 %. It will permit calibration in any of 12 different pressure units, using the existing weight set.

What's in the Box

• P3031-KGCM2 Liquid Lubricated Gas Deadweight Tester

• Series 3 nonmagnetic austenitic stainless steel masses

• Operating fluid (where applicable) and spare seals

• Detachable lid

• Accredited calibration certificate

• Adaptors

• Rugged case