CA Cold Room Door Foaming in China

Illustration notice. Process illustrations are not verified photographs of this installation.

Project reference basis. Figures and configuration details are reported in the supplied project brief. They are reference values for the stated application, rather than verified acceptance results or a guarantee for another installation. Confirm the source records, material, tooling, operating schedule and test method when assessing a comparable project.

A leading cold chain logistics equipment and industrial door group in Eastern China deployed Haifeng’s heavy-duty discontinuous door foaming line. The installation was commissioned to manufacture high-performance, extra-thick (220 mm) airtight sliding doors for a major 50,000-ton agricultural controlled-atmosphere (CA) cold storage facility.

Prior to this installation, the client utilized legacy low-pressure single-point dispensing equipment. Injecting 75 kg of resin across an oversized 3.5 m x 2.2 m x 0.22 m panel took over 65 seconds, allowing the leading edge of the chemical front to cream and crosslink before the cavity was filled. This created internal weld lines and severe exothermic core shrinkage. When deployed under -30°C freezer operations, the finished doors bowed inwards by up to 15 mm, causing perimeter rubber gaskets to unseat and resulting in costly air infiltration and icing.

Haifeng engineered a complete heavy-section foaming cell centered on the HF-CRD250-LP system. Featuring synchronized dual-head staggered high-pressure injection and a 200-ton heated hydraulic clamping press, the line eliminated flow knit lines, achieving a 95.5% closed-cell structure and holding low-temperature dimensional shrinkage under 0.42%.

Review point: The model suffix LP does not identify its pressure class: the supplied circuit is 15–17.5 MPa high-pressure impingement. A 75 kg shot in 18.2 s implies 247.3 kg/min, exceeding the stated combined 180 kg/min maximum; reconcile shot mass, time and head aggregation. Injection time differs from mold dwell and full cure.

Concept illustration: Generated concept illustration for process discussion; not a photograph of the specified machine, a customer facility or a delivered project.

Configuration reported in the supplied brief.

Haifeng engineered an automated heavy-panel discontinuous production cell featuring sequential fluid displacement. Pre-assembled 220 mm door shells incorporating welded internal frame reinforcements and heating wires are transferred onto the preheated lower platen of a 200-ton hydraulic press.

Chemical components—high-density rigid polyol and polymeric isocyanates—are conditioned in dual 300 L jacketed tanks at 22°C. The HF-CRD250-LP unit displaces chemicals at 16.5 MPa via servo-driven axial piston pumps under continuous Coriolis mass flow measurement.

Twin high-pressure impingement mixing heads engage the door’s dual fill ports. The master controller executes a staggered timing sequence, initially injecting at the primary door base before triggering the second head to flood the upper panel, discharging 75 kg of resin within 18 seconds.

The hydraulic press maintains 1.5 bar counter-pressure across the platens, while 45°C water circulation ensures even expansion. The door cures in-mold for 22 minutes to relieve core reaction stresses. Upon demolding, finished doors exhibit verified warpage deviations of less than 1.2 mm across the 3.5-meter length.

The model suffix LP does not identify its pressure class: the supplied circuit is 15–17.5 MPa high-pressure impingement. A 75 kg shot in 18.2 s implies 247.3 kg/min, exceeding the stated combined 180 kg/min maximum; reconcile shot mass, time and head aggregation. Injection time differs from mold dwell and full cure.