SensoControl measuring connections for easy connection of pressure circuit and measuring device

SensoControl Test Points for Easy Connection of Pressure Circuit and Measuring Device

Test points from the SensoControl series reliably connect pressure circuits with measuring devices, test fixtures, and service equipment in high, low, and vacuum pressure applications. Designed for industrial testing and maintenance processes, these connection solutions allow for quick assembly, tight interfaces, and repeatable measurement conditions. Typical applications include pressure monitoring, sampling, cylinder bleeding, and the locking of hydraulic and pneumatic systems during commissioning and fault diagnosis.

Design Features and Materials

SensoControl test points are offered in variants made of brass (MS), stainless steel (AISI 316 / 1.4401), and technical plastics to cover different corrosive stresses and pressure requirements. Brass versions offer a good price-performance ratio and electrical conductivity for potential-guided measurements. Stainless steel models are used in aggressive media, elevated hygiene standards, or chemical exposure. Plastic housings are used in cost-sensitive, low-corrosion applications and for weight reduction.

Housing forms include straight screw-in or valve connections, angle connections, quick couplings, as well as flare and conical connections. Housing designs consider switching and measuring direction, flow optimization, and mounting access. Surface finishes range from bright turned to nickel-plated to polished/passivated for stainless steel.

Connection Types, Threads, and Sealing Systems

SensoControl test points cover common connection standards: BSPP/BSPT (G, R), NPT, ISO 228/1, DIN 3852, as well as metric screw-in threads. For measuring device connections, 1/4" BSP, 1/8" BSP, and M10x1 are available as standard. Different sealing systems are used for pressure-tight connections: flat gaskets made of PTFE or NBR for static applications, O-rings (NBR, FKM, EPDM) for dynamic or repeated couplings, and metal sealing cones (e.g., 24° cone) for high-pressure screw connections. For high temperatures, silicone-free materials and graphite gaskets are used. The choice influences the temperature range, media resistance, and repeatability.

For measuring devices and test lines, integrated union nuts with sealing cones are often offered, allowing quick connection without additional sealing. Quick couplings feature pawls and integrated valves that enable pressure-free disconnection.

Pressure Ranges, Leak Rates, and Safety Aspects

SensoControl test points are designed for operating pressures from vacuum to several hundred bar. Standard variants typically cover 0…400 bar; special versions achieve higher maximum pressures with a more compact design. Permissible working pressures, test pressure, and burst or failure data are documented for each component. Notch-free flow guidance and precise seating surfaces minimize leak rates, which should be verified in critical applications with helium or hydrogen leak tests. Products with metal-to-metal seals are suitable when minimal leak rates are required.

Safety points: correct thread and seal handling reduce damage to measuring devices, check valves and pressure relief bores protect personnel during depressurization, and visually accessible locking mechanisms provide information about closed or open states. For work on high-energy systems, combinations with vent and shut-off valves are recommended.

Application Cases and Practical Examples

Practical Example 1 — Hydraulic Test Bench, Commissioning: When testing a hydraulic unit, a SensoControl 1/4" BSP stainless steel test point is screwed into the pump's test bore. A connected manometer measures the pressure increase at a defined flow rate. For leak testing, a helium coupling is used; thanks to the metal seal, the leak rate remains below 1·10^-6 mbar·l/s. After the test, the quick coupling automatically disconnects and closes the measuring line, allowing the system to continue operating without pressure loss.

Practical Example 2 — Cylinder Bleeding in Assembly Hall: In the final assembly of linear axes, a plastic test point with 1/8" BSP is mounted on a bleed bore. An NBR O-ring seal makes the connection suitable for workshop air up to 8 bar. The bleed valve allows controlled removal of residual air during piston positioning; the connection can be quickly removed and reattached for tightness qualification.

Practical Example 3 — Sampling in Production Process: In the process monitoring of a refrigeration system, a test point is integrated into a separation point, which allows defined sampling under vacuum by means of a shut-off valve. The user opens the valve, fills the sample bottle, and closes it, with the integrated check function preventing contamination of the measuring circuit. The choice of AISI 316 stainless steel protects against corrosive coolants.

Selection Criteria for the Right Component

The selection depends on system pressure, medium, temperature, mounting space, and required mounting frequency. For permanent measuring points, screwed variants with flat gaskets or conical seats are suitable; for frequent measuring cycles, quick couplings with integrated closures or union nuts with O-rings are advisable. If electrical potentials are relevant, a conductive brass or stainless steel version is recommended. For aggressive media and food applications, certified stainless steel and PTFE seal combinations are mandatory to avoid corrosion and media contamination.

• Choose material according to medium and temperature; choose seal according to media resistance; choose connection type according to existing measuring devices and threads.

Integration into Test Procedures and Maintenance

In test benches, test points are preferably mounted with short, pressure-stable lines and minimal transitions to reduce dead spaces. Regular visual inspection of the sealing surfaces, replacement of O-rings after a defined number of cycles, and torque control of the screw-in connection ensure measurement accuracy and service life. For traceability, part numbers, material certificates, and test documents must be archived. Replacement seals should be checked for material conformity, especially for FKM/EPDM and media critical for compatibility.

Compatibility with Measuring Devices and Accessories

SensoControl test points are compatible with standard manometers, pressure transmitters, pressure switches, and laboratory quick couplings. Adapters to NPT or metric allow adaptation to existing equipment. For calibration work, combining them with calibrated measuring lines and thermocompatibility documents is recommended to correctly account for temperature dependencies of the measured values. Accessories such as protective caps, dust covers, and mounting flanges allow for better handling in harsh environments.

Further technical information and design documents can be found on the Technology overview page: https://maku-industrie.de/technik. Examples of specific applications and case studies are documented under https://maku-industrie.de/anwendungsbeispiele.

Test and Standard Conformity

SensoControl test points comply, depending on the version, with relevant standards for pressure components and pipe connections, as well as material standards (e.g., EN, DIN, ASTM). Test documentation includes pressure testing (hydrostatic/pneumatic), leak testing, and material certificates. If required, customer-specific test certificates and hardness, tensile, or chemical analyses are available. For safety-relevant applications, performing test cycles according to internal maintenance instructions is mandatory.

Procurement and Personalization

Standard components are available from stock; custom designs (different threads, special sealing materials, longer screw-in threads, or additional bores) are offered according to technical drawings. Marking is done by laser engraving or embossing with article number, pressure range, and material specification. For batches with traceable documentation, test plaques and individual packaging solutions can be selected.

FAQ

Which seal is suitable for aggressive coolants?

For aggressive coolants, a combination of stainless steel housing (AISI 316) and PTFE or FKM O-rings is preferred; PTFE offers the highest chemical resistance, FKM high temperature and oil resistance. Material compatibility must be checked against the media data sheet.

How often should O-rings be changed with frequent measurements?

Change intervals depend on media, temperature, and frequency; as a guideline, we recommend cyclical replacement after 6–12 months in continuous operation or after defined 1,000–5,000 switching cycles. Visual inspection and functional testing are mandatory before each critical measurement.

Can I use SensoControl test points for vacuum applications?

Yes. Special sealing variants (e.g., metal seals or specified FKM/PTFE combinations) and precisely manufactured seating surfaces guarantee tightness in the vacuum range; test documents for leak rates and material selection should be requested in advance.