DA12 Differential Pressure Gauge for Pumps and Hydraulic Circuits | Fischer

Key Features: Fischer DA12 Differential Pressure Gauge

The Fischer DA12 is a rugged mechanical pressure gauge designed to measure and indicate differential pressure, positive pressure and negative pressure in liquids and gases.

It is particularly suitable for industrial applications requiring reliable local indication, including pump monitoring, filter monitoring, hydraulic circuits, heating systems and supply-and-return lines.

The DA12 uses a rugged diaphragm measuring system that is insensitive to demanding environmental conditions. The same measuring principle enables the instrument to measure differential pressure, positive gauge pressure or vacuum, depending on the process connections.

Under normal conditions, the spring forces acting on both sides of the diaphragm are balanced. The applied pressure moves the diaphragm system against the measuring springs, and this movement is mechanically transmitted to the indicating pointer.

During an overload condition, the diaphragm rests against internal metal surfaces that limit its movement and help protect the measuring system. The instrument can withstand one-sided overpressure up to 25 bar, depending on the selected range and configuration.

The DA12 product family provides ranges from 0–250 mbar up to 0–16 bar, as well as selected vacuum and compound ranges. It can operate with static pressure up to 16 bar and has a measuring-system nominal pressure of 25 bar.

The instrument features a clearly visible analogue dial, front-accessible zero-point adjustment and a housing suitable for wall mounting or panel installation.

It can be configured with aluminium, HART-COAT®-protected aluminium or stainless-steel pressure chambers, together with NBR, VITON® or Inconel 718 diaphragms and seals, depending on the measuring range and medium compatibility.

As a Fischer distributor, Garma Electrónica provides technical support for selecting the correct range, materials, process connections and mounting arrangement.

Main Specifications: Fischer DA12 Differential Pressure Gauge

• Measured variables: differential pressure, positive pressure and negative pressure.
• Media: liquids and gases compatible with the selected materials.
• Main application: local pressure indication and monitoring in industrial processes.
• Minimum available range: 0–250 mbar.
• Maximum standard range: 0–16 bar.
• Other available ranges: vacuum and compound ranges, depending on version.
• Measuring principle: mechanical diaphragm system with measuring springs.
• Accuracy: ±2.5% of the upper range value.
• Maximum static pressure: up to 16 bar for the 250 and 400 mbar ranges.
• Measuring-system nominal pressure: 25 bar.
• Test pressure: 1.5 times the nominal pressure.
• One-sided overpressure resistance: up to 25 bar, depending on range.
• One-sided negative-pressure resistance: down to −1 bar for the specified low-pressure ranges.
• Zero-point adjustment: accessible from the front of the scale.
• Indication: analogue dial with pointer.
• Power supply: not required.
• Output: local mechanical indication.
• Ingress protection: IP55 according to EN 60529.
• Ambient temperature: −10 to +70°C.
• Medium temperature: −10 to +70°C.
• Storage temperature: −15 to +75°C.
• Mounting position: vertical.
• Pressure chambers: aluminium, HART-COAT® aluminium or stainless steel, depending on version.
• Measuring diaphragm: NBR, VITON® or Inconel 718, depending on range.
• Seals: NBR or VITON®.
• Internal components: stainless steel.
• Connections: G¼ female thread, G¼ male thread or tube fittings.
• Mounting: wall or panel mounting using an accessory kit.

Applications and Benefits: Fischer DA12 Differential Pressure Gauge

Pump Monitoring

The DA12 can compare pump suction and discharge pressure. This differential-pressure value helps confirm that the pump is operating at its intended duty point and supports the detection of performance loss, blockages or abnormal conditions.

Heating-System Supply and Return Monitoring

A key application of the Fischer DA12 is differential-pressure measurement between supply and return lines in heating installations.

This measurement helps verify hydraulic balancing, monitor fluid circulation and detect changes in the resistance of pipes, valves, radiators or heat exchangers.

Industrial Filter Monitoring

The instrument can be connected upstream and downstream of a filter to display its pressure loss. A progressive increase in differential pressure indicates contamination and supports maintenance or replacement planning.

Hydraulic Circuits

The DA12 can measure pressure differences in water circuits, thermal-fluid systems and other compatible liquids. Its mechanical design provides local indication without dependence on electrical power or a PLC.

Heat Exchangers

Differential pressure between a heat exchanger inlet and outlet provides information about the internal condition of the equipment. An increase in pressure loss may indicate fouling, deposits or flow restrictions.

Valves and Control Components

Measurement upstream and downstream of a valve helps determine the generated pressure loss, verify valve operation and analyse the hydraulic behaviour of the installation.

Positive and Negative Pressure Measurement

In addition to differential pressure, the DA12 diaphragm system can measure positive gauge pressure or vacuum when the high- and low-pressure chambers are connected accordingly.

Demanding Industrial Environments

Its rugged design makes the instrument suitable for machine rooms, energy installations, process plants, hydraulic equipment and systems exposed to demanding environmental conditions.

Contaminated or Aggressive Media

The DA12 can be adapted to selected contaminated or chemically aggressive media by choosing appropriate pressure-chamber, diaphragm and seal materials. Material compatibility must be verified before defining the product code.

Operation Without Electrical Power

As a mechanical instrument, it continues to provide local indication during a power failure or automation-system shutdown.

Technical Advantages of the Fischer DA12

• Differential, positive and negative pressure measurement.
• Suitable for liquids and gases.
• Ranges from 250 mbar to 16 bar.
• Rugged construction for demanding industrial environments.
• Protection against one-sided overload.
• Mechanical indication without electrical power.
• Front-accessible zero-point correction.
• Different materials for process-medium compatibility.
• Wall or panel mounting.
• Wide range of process connections.
• Particularly suitable for pumps, filters and heating circuits.

Available Materials and Versions

• Painted aluminium pressure chamber.
• Aluminium pressure chamber with HART-COAT® surface protection.
• Stainless-steel 1.4305 pressure chamber.
• NBR diaphragm and seals.
• VITON® diaphragm and seals.
• Inconel 718 diaphragm for selected ranges.
• Brass or stainless-steel process connections.
• Tube fittings for 6, 8 or 10 mm tubing.

Accessories for the Fischer DA12

• DZ11 installation kit for converting wall mounting to panel mounting.
• DZ23 three-spindle valve manifold for isolation and pressure equalisation.
• DZ24 valve manifold with an additional vent valve.
• Fischer MZ measuring accessories and damping components.
• Siphons and protection accessories for special process conditions.

Information Required to Select the Fischer DA12

The following application data should be defined before selecting the gauge:

• Minimum and maximum differential-pressure range.
• Requirement to measure differential pressure, positive pressure or vacuum.
• Maximum static system pressure.
• Liquid or gas type and composition.
• Fluid and ambient temperature.
• Chemical compatibility of diaphragms, seals and chambers.
• Requirement for NBR, VITON® or Inconel 718.
• Aluminium, HART-COAT® or stainless-steel pressure chamber.
• Process-connection type and size.
• Wall or panel mounting.
• Requirement for a valve manifold or isolation accessories.
• Presence of contamination, particles or aggressive media.

Garma Electrónica provides technical support for selecting the measuring range, static pressure, materials, process connections and accessories required for each differential-pressure application.