Measuring connections – find manufacturers and suppliers

Measuring connections are small, precisely manufactured fittings that are installed in pipelines, hydraulic or pneumatic systems to monitor pressure, temperature, flow or other process variables or to take samples.

They are typically used to connect a measuring device, a pressure gauge, a sensor or a sampling hose quickly and safely without draining the system or taking it out of operation.

Below is an overview of the function, types and use of measuring connections, as well as an overview of their advantages:

How measuring connections work:

Measuring connections consist of a threaded or flanged housing, an integrated seal and often a non-return or valve element.
In normal operation, the connection is self-closing or closed by a screw, cap or valve.
If a measuring device, e.g. a test connection for hydraulic pressure, is fitted, the valve element opens and creates a pressure-tight connection to the process.
After measuring, the device is disconnected again and the valve closes automatically - without loss of media and without venting the system.
This mode of operation enables fast, reliable measurements even under pressure.

Types of measuring connections:

There are different designs, depending on the medium, pressure rating and area of application:

1. Screw test connections (test plugs):
   Small, compact connections, usually with cone or ball valve, for hydraulic and pneumatic systems.
   Example: Test connections with M16x2 thread in hydraulic systems.
2. Quick-coupling test connections:
   With quick release for rapid connection and disconnection of measuring devices, without tools.
3. Sampling test connections:
   Especially for taking liquid or gas samples from running processes.
4. Flange or threaded measuring connections:
   For larger pipes, high pressures or high flow rates.
5. Sensor/transmitter measuring couplings:
   With integrated ports for fixed sensor installation for pressure, temperature or flow sensors, for example.

Use of measuring connections:

Measuring connections can be found in almost all industrial sectors:

1. Hydraulic and pneumatic systems:
Pressure and temperature measurement on pumps, valves and lines.
Diagnosis of leaks or pressure losses.

2. Process industry (chemicals, petrochemicals):
Taking samples for laboratory analysis, monitoring process parameters, e.g. pH, conductivity and temperature.

3. Energy and power plant technology:
Measurement of steam pressure, feed water or cooling circuits without system downtime.

4. Food and pharmaceutical industry:
Hygienic measuring connections for sampling or online measurements in sterile processes.

5. Heating, ventilation and air conditioning technology (HVAC):
Control of operating pressures, temperatures and flow rates in building services systems.

6. Laboratory and test equipment:
Quick connection of test equipment and measuring devices.

Advantages of measuring connections:

• Quick, simple measurements: No draining or dismantling of the system required.
• Safety: Measurements under pressure without loss of media or risk of injury.
• Flexibility: Connection of different measuring devices, even temporarily.
• Ease of maintenance: Fast troubleshooting and diagnosis of systems.
• Clean sampling: Direct access to the medium without contamination.
• Wide choice of materials: Stainless steel, brass, special alloys or hygienic materials for every application.
• Compact design: Can also be integrated into confined system areas.
• Cost efficiency: Reduces downtime, maintenance and personnel costs.

Measuring connections are indispensable interfaces for monitoring, diagnostics and sampling in technical systems.
They enable safe measurements and sampling during operation, increase the efficiency and safety of maintenance and quality assurance and are standard in almost all industries.
By selecting the right type, material and sealing system, measuring connections can be optimally adapted to the medium, pressure, temperature and hygiene requirements.

Here is an overview of the most important criteria to look out for when purchasing measuring connections:

As measuring connections are in direct contact with media and are often exposed to high pressures or aggressive substances, careful selection is crucial when purchasing. This is the only way to ensure reliability, safety and cost-effectiveness.

• Before measuring connections are procured, the area of application should be precisely defined:
• Is it hydraulic oil, compressed air, water, steam or chemicals?
• Are the media aggressive, abrasive or hygienically sensitive?
• The material and seals of the measuring connection must be suitable for the medium. In corrosive environments (chemicals, offshore), stainless steel or special alloys are recommended; in the food and pharmaceutical industries, hygienic materials with smooth surfaces are recommended.
• Measuring connections must be designed for the maximum operating pressure and the highest operating temperature.
• Check the nominal pressure, e.g. 250 bar in hydraulic systems and possible pressure peaks.
• Select connections that retain their tightness even at very high or very low temperatures.
• For frequent measurements under pressure, a particularly safe, leak-free design is important.
• There are different designs that offer advantages and disadvantages depending on the requirements:
• Screw connections (test plugs) are compact and cost-effective for fixed installation points.
• Quick-release couplings allow particularly fast, tool-free connection and disconnection of measuring devices.
• Sampling connections are specially designed for clean, contamination-free sampling.
• Connections for permanently installed sensors should have standardized threads and seals.
• The choice of design depends on the installation location, switching frequency, measuring device and hygiene requirements.
• Measuring connections must match the existing system. Metric threads, BSP, NPT or flange standards.
• Check whether adapters are necessary or whether the connection is directly compatible.
• International norms and standards, ISO, DIN, SAE facilitate replacement and spare parts procurement.
• Make sure you use reliable sealing systems (e.g. O-rings made of NBR, Viton or EPDM) suitable for the medium.
• For high-pressure applications, self-closing valves or non-return mechanisms are useful to ensure that no medium escapes when disconnecting.
• Protective caps or screw plugs protect the measuring point from dirt and damage.
• Measuring connections should be designed so that measuring devices can be connected quickly, safely and without great effort.
• Quick couplings and self-sealing systems are particularly useful in maintenance areas with many measuring points.
• Check whether a pressureless connection is possible or whether a pressure release is necessary.
• Rely on high-quality materials and precise manufacturing to ensure tightness and a long service life.
• Check whether the manufacturer offers quality certificates such as ISO 9001 and industry-specific approvals, DVGW, FDA, WRAS, ATEX.
• Corrosion resistance and robust construction extend service life.
• Measuring connections should be easily accessible and low-maintenance.
• Check whether wearing parts, e.g. seals, are easy to replace and can be delivered quickly.
• Good documentation, assembly instructions and CAD data make installation and servicing easier.
• The purchase price is only part of the calculation.
• Better quality and suitable designs reduce leakages, downtimes and personnel costs for maintenance and measurement.
• High-quality measuring connections often pay for themselves through durability and time savings with every measurement.

When purchasing measuring connections, more is important than just the price: The medium, pressure, temperature, material, design and standardization must be matched to the respective system. If you choose carefully, you will get connections that are safe, durable and compatible and make measurement reliable and easy during operation. This reduces downtimes, increases process reliability and reduces overall costs over the life cycle.

Measuring connections can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Measuring connections from all over the world can be found on Exportpages.