Mechanical pressure control valve for refrigeration systems

Danfoss has expanded its refrigeration portfolio with the AXV mechanical pressure control valve platform, developed for hot gas bypass and liquid injection applications in commercial and industrial cooling systems. The valve platform is designed to simplify installation, improve operational stability and reduce applied system costs across multiple refrigeration applications.

Pressure regulation for refrigeration and cooling systems
The AXV platform has been developed for applications including air dryers, water chillers, ice cream machines and frozen beverage dispensers. Unlike superheat regulators, the AXV functions as a pressure regulator that controls evaporator pressure to maintain stable evaporation temperature across the full evaporator surface.

This operating principle makes the valve suitable for refrigeration systems where maintaining constant evaporating pressure and temperature is critical for process stability and cooling performance.

Two valve variants for different refrigeration functions
The AXV platform consists of two dedicated valve variants designed for separate application areas.

The AXV-H version is intended for hot gas bypass applications. Installed between the high-pressure and low-pressure sides of the refrigeration circuit, the valve maintains compressor suction pressure by injecting hot gas into the system. By adapting compressor capacity to actual evaporator load conditions, the AXV-H supports stable evaporation pressure under variable operating loads.

According to Danfoss, the AXV-H is designed as a replacement for existing TUH and TCHE hot gas bypass valves while covering up to 20 percent higher capacity within the same application range.

The AXV-I version has been developed for pressure-controlled liquid injection applications. When evaporating pressure drops below the defined setpoint, the valve opens proportionally to stabilize the system pressure. This enables constant evaporation temperature control across the evaporator surface.

Stainless steel platform with laser-welded diaphragm technology
The AXV valve platform is based on a stainless steel construction featuring laser-welded dual diaphragm technology and a 45 mm diaphragm designed for stable and precise pressure regulation.

Technical characteristics include internal pressure equalization, low internal friction for rapid response behavior and reduced pressure drop during valve opening. The mechanical spring adjustment range extends from 1 to 7 bar, or up to 11 bar when operating with R410A refrigerant.

The valve platform supports maximum working pressures of 34 bar for low- and medium-pressure applications and 49 bar for high-pressure systems. The operating medium temperature range extends from -25 °C to 130 °C.

The valves are compatible with A1, A2L and A3 refrigerants, excluding R744 and R717 refrigerants, and comply with cULus, UL207, CE and Gost certification requirements.

Simplified installation and reduced system complexity
Installation simplicity was a central development objective for the AXV platform. The valves incorporate bimetallic connectors designed for simplified brazing without requiring wet cloths, cooling clamps or external sensing elements.

The elimination of external bulbs and capillary tubes reduces the number of system components and lowers installation complexity. This contributes to reduced assembly effort, simplified service procedures and lower applied refrigeration system costs.

Durability testing and manufacturing reliability
The AXV platform has undergone multiple validation procedures including MOPD testing, lifecycle and fatigue testing, external leakage testing, capacity modulation testing and salt spray reliability testing.

Production is carried out on a dedicated European manufacturing line intended to support supply continuity and consistent product quality for refrigeration OEMs and system integrators.

Refrigeration portfolio transition and application coverage
The AXV platform expands the Danfoss refrigeration valve portfolio by replacing existing TUH and TCHE hot gas bypass valves while also providing a pressure-controlled expansion alternative for refrigeration applications. The platform also reduces product code complexity through its wide manual adjustment range and supports planned portfolio migration activities before the end of 2026.

Additional Context: technical specifications and competitive benchmarking not included in the original announcement
In the refrigeration pressure control valve segment, manufacturers including Emerson, Parker Hannifin and Castel offer comparable hot gas bypass and evaporator pressure regulation technologies for commercial refrigeration and HVAC applications. Key benchmarking parameters include pressure regulation stability, refrigerant compatibility, installation complexity, maximum working pressure, response time and diaphragm durability.

Mechanical pressure-regulating valves continue to be widely used in refrigeration systems requiring stable evaporator temperature control without dependence on electronic control architectures. In retrofit applications, simplified installation and compatibility with lower-GWP refrigerants are becoming increasingly important selection criteria.

The presented solution is differentiated primarily through the combination of laser-welded dual diaphragm technology, broad refrigerant compatibility, elimination of external sensing components, extended operating pressure range and dual-function application coverage within a single mechanical valve platform.

Edited by Maria Brueva, Induportals editor – adapted by AI.

www.danfoss.com