The Additel ADT 901B is a hand-operated low pressure test pump designed to generate pressures from -6 psi (-0.4 bar) to 6 psi (0.4 bar) for precision calibration of low pressure instruments such as transmitters, gauges, and switches.

A high-quality screw press enables fine pressure adjustment with resolution up to 0.1 Pa (0.001 mbar). The isothermal bellows chamber reduces the effects of environmental temperature changes, ensuring exceptional stability during micro-pressure calibrations. Unlike traditional pumps that use troublesome check valves, the ADT 901B has no non-returning valve, resulting in minimal maintenance and remarkably stable pressure output.

Two hand-tight quick connectors for test and reference gauges allow easy connection and disconnection without PTFE tape or wrenches. Multiple port options are available including 1/4 NPT, 1/2 NPT, 1/4 BSP, 1/2 BSP, and M20×1.5 female.

Construction materials include stainless steel ram and adapters, with body materials of stainless steel and aluminum. Seals are Buna-N, PTFE, and copper alloy for durability. The pump weighs only 3.5 lb (1.6 kg) and measures 5.7 × 9.65 × 6.5 inches.

Each unit includes 20 spare O-rings and a user manual. Applications include calibrating low pressure sensors in pharmaceutical clean rooms, HVAC systems, medical devices, and research laboratories.

Features

• Pressure range: -6 to 6 psi (-0.4 to 0.4 bar)
• 0.1 Pa (0.001 mbar) adjustment resolution
• Isothermal bellows chamber for temperature stability
• No check valve design – minimal maintenance
• Hand-tight quick connectors – no tools or PTFE tape
• Multiple port options: 1/4 NPT, 1/2 NPT, 1/4 BSP, 1/2 BSP, M20×1.5
• Portable: 3.5 lb (1.6 kg)
• Stainless steel and aluminum construction
• Includes 20 O-rings and manual
• 1-year warranty