Maintaining a constant temperature environment in the bottle-blowing workshop is critical for ensuring stable production of plastic containers such as PET bottles, particularly in scenarios demanding high cleanliness and process precision like pharmaceutical and food packaging. The core approach involves using precision air conditioning systems, effective insulation structures, and intelligent monitoring to control workshop temperatures between 20°C and 25°C, with fluctuations kept within ±1°C.

I. Establishing Reasonable Temperature and Humidity Control Standards

Different products and processes demand varying levels of environmental stability, necessitating precision-grade settings based on actual requirements:

Standard Blow Molding Workshop: Temperature controlled at 18°C–26°C, relative humidity <60% RH;
High-Precision Pharmaceutical Packaging Workshop: Requires 22±0.5°C, humidity controlled between 45%–60% to prevent preform moisture absorption affecting blow molding quality;
Excessive temperature variations can cause uneven preform heating, condensation formation, or reduced mold cooling efficiency, leading to bottle deformation, stress cracks, and other issues.

For instance, when workshop temperatures fall below the dew point, preform surfaces may condensate. Moisture vaporizes during high-temperature blowing, potentially causing “bubbles” or “white haze” defects on bottle walls.

II. Establishing an Efficient Constant Temperature and Humidity Air Handling Unit (AHU) System

The air handling system is central to temperature control and must meet the following requirements:

Employ a combined air handling unit (AHU) + PID intelligent regulation

Achieve precise coordinated control of heating/cooling, humidification, and dehumidification;
Include reheat functionality to prevent energy waste from excessive cooling.

Optimize airflow organization design

Employ top-supply/bottom-return or side-supply/bottom-return configurations to ensure uniform air distribution;
Install laminar flow hoods in critical zones (e.g., bottle-exit points of blow molding machines) to provide vertical unidirectional flow protection, preventing thermal disturbances from compromising clean environments.

Implement variable frequency control and energy-saving technologies

Automatically adjust fan speed and cooling capacity based on load variations;
Integrate renewable energy sources like ground-source heat pumps and photovoltaic power supply to reduce long-term operational costs.
III. Optimizing Workshop Envelope and Sealing

Effective thermal insulation is fundamental to maintaining constant temperature:

Table
Structural Component    Recommended Materials & Practices
Walls & Ceilings    Color-coated steel sandwich panels (polyurethane or rock wool core), thermal conductivity ≤0.6 W/(m²·K)
Floors    Anti-static epoxy self-leveling flooring with heat resistance, wear resistance, and easy cleaning properties
Doors and Windows    Double-pane insulated glass windows; doors with automatic closing and interlocking mechanisms to prevent air convection
Wall Penetrations    All pipe penetrations must be sealed to avoid thermal bridging

Special Note: Install thermal barriers around heating furnaces to prevent localized high temperatures from disrupting overall temperature control balance.

IV. Enhance Equipment and Process Coordination Management

Control heat sources from blow molding machines themselves

Blow molding furnace operating temperatures may exceed 100°C; an independent exhaust system is required to promptly remove hot air.
Install drainage channels at the machine base to collect debris, preventing dust accumulation that impedes heat dissipation.

Ensure mold cooling efficiency

Mold cooling water temperature should be maintained between 5°C–10°C.
The cooling water system must operate in a closed loop to prevent interference from external temperature fluctuations.

Compressed Air Purity and Temperature Control

Compressed air for blowing must undergo triple filtration (water removal, oil removal, bacteria removal), with terminal 0.01μm filters installed;
During high-temperature seasons, enhance air compressor cooling to prevent excessive blowing temperatures from affecting bottle shaping.
V. Implement Real-Time Monitoring and Intelligent Operations
Install temperature and humidity sensors at critical workshop locations for 24/7 data collection and anomaly alerts;
Remotely monitor environmental parameters via mobile app or central control platform, supporting historical data traceability and trend analysis;
Periodically calibrate sensors and HVAC control systems to ensure measurement and regulation accuracy.