Many issues in the refrigeration circuit do not show up as a clear threshold violation, but as short, local two‑phase conditions: a slug of liquid in the suction line, gas content in the liquid line, or unstable transitions during load changes. These moments are critical for compressor protection and efficiency—yet in day‑to‑day operation they are often hard to pinpoint because they can only be inferred indirectly from pressure and temperature values.
The KRIWAN INT700 closes this gap. As an optical phase sensor for external mounting on the sight glass, it detects phase changes directly at the measurement point—without opening the circuit. This turns a difficult‑to‑diagnose condition into actionable information for protection logic, trend analysis, and service.
In RACHP systems, stable operating conditions in the refrigeration circuit determine efficiency, availability, and component protection. Many conditions are evaluated using pressure and temperature measurements (e.g., superheat/subcooling). What is often missing, however, is direct, location‑specific information on whether the medium at the measurement point is single‑phase or two‑phase.
Especially during dynamic load changes, start/stop operation, or as components age, conditions can occur that become visible in standard variables only indirectly or with a time delay.
Gas content in the liquid line
Gas content in the liquid line
On the high‑pressure side, a stable single‑phase liquid condition in the liquid line is often a prerequisite for efficient, trouble‑free operation. Two‑phase content—especially flash gas—typically indicates insufficient subcooling, undercharge, or relevant pressure losses in the line.
Liquid content in the suction line
Liquid content in the suction line
On the low‑pressure side, liquid content in the suction line is often an indication of critical operating conditions. It is relevant both from a compressor‑protection perspective and for operational optimization.
On the low‑pressure side, liquid content in the suction line is often an indication of critical operating conditions. It should be taken seriously both for compressor protection and for operational optimization and energy‑efficient system operation.
The INT700 signal enables reliable detection of critical conditions and provides not only event information but also signal trends for service and troubleshooting. The sensor can help stabilize superheat and run the system closer to an optimum operating point—without tolerating safety‑critical wet‑vapor conditions.
On the high‑pressure side, a stable single‑phase liquid condition in the liquid line is often an essential prerequisite for efficient, trouble‑free operation. Two‑phase content—especially flash gas—typically indicates insufficient subcooling, undercharge, or relevant pressure losses in the line.
Flash‑gas monitoring with the INT700 helps keep subcooling under control, detect undercharge or leaks early, and plan maintenance based on actual condition—before efficiency and system performance noticeably deteriorate.
How the INT700 works – phase information from the sight glass
The flow diagram shows the core of the INT700: the sensor mounts externally on the sight glass and uses a reflection‑based optical measurement principle to detect phase changes in the medium—without opening the refrigeration circuit. Changes in optical reflection are captured as a signal and can be used as clear event information (digital output) or as a continuous trend (analog output) in control and monitoring systems.
Thanks to installation at the sight glass and the ability to detect both gas‑ and liquid‑dominated states, the INT700 offers a broad range of applications. Examples include:
In addition, further applications are expected to develop over time—especially where operators and service organizations increasingly focus on condition‑based maintenance, remote diagnostics, and energy optimization.
Depending on the system concept and integration requirements (digital or analog output), different application and configuration options are available. Talk to our specialists—we support you with selection, installation point, and parameterization.
| Parameter | Value |
|---|---|
| Measurement principle / mounting | Optical, reflection‑based; external mounting on the sight glass |
| Medium temperature | −40 °C to +70 °C |
| Mechanics | Vibration‑resistant mounting; sealed to reduce icing effects |
| Supply | 24 V DC |
| Electrical connection | 3‑pin M8 connector |
| Service | USB‑C (KRIWAN Service App), status LED |
Depending on the system concept and integration requirements (digital or analog output), different application and design options are available. Talk to our specialists—we support you with selection, installation point, and parameterization.
Start of series production: planned for Q2/2027. Specifications on output variants, configuration, and compatibility will be finalized and published as part of the market launch.
