Home / What is the difference between an injection molding hopper dryer and a dehumidifier?

What is the difference between an injection molding hopper dryer and a dehumidifier?

2024/02/28 By 兰兹

injection molding hopper dryer

The complete injection molding process includes the injection molding machine and the injection robot, which also consists of the injection molding hopper dryer and dehumidifier. Because moisture in plastic raw materials can significantly affect the quality and integrity of the finished product, two standard tools used for this purpose are injection plastic bucket dryers and dehumidifiers. In this guide, we will explain the differences between these two machines and the characteristics each has.

Learn about the functions of an injection molding hopper dryer:

The injection molding hopper dryer is suitable for drying plastic granules. It uses high-temperature hot air to process raw materials and fully dry them. A dryer comprises a hopper or chamber where one places a plastic resin for drying. Hot air circulates through the hopper, heating the resin and evaporating any remaining moisture within the material. In addition, the plastic hopper dryer has precise temperature and airflow control mechanisms to meet different drying conditions. Users can also adjust temperature settings to meet the specific requirements of various plastic resins and prevent overheating or thermal degradation. Likewise, the control panel changes the airflow rate to provide even drying.

injection molding hopper dryer 1

Design, composition, and operation of injection plastic hopper dryer

The main components of an injection molding hopper dryer include the hopper, heating element, blower or fan, temperature and humidity sensors, and control panel. They design all stainless steel raw material contact surfaces to ensure they do not contaminate the raw materials. There is also a viewing window outside the barrel base to observe the internal working conditions directly. It also adopts the curved design of the upward-blowing dryer’s heating tube to avoid damage caused by raw materials falling into the tube. It has safety protection devices for things such as over-temperature and overload.

In terms of operation, the injection molding hopper dryer is generally located above the injection molding machine and dries the plastic resin through a set process. Plastic resin is loaded into the hopper through an automatic loading system, and drying parameters, including temperature, airflow, and drying time, are set on the control panel according to the specific requirements of the resin to be dried. During the drying process, the conditions in the hopper can be monitored through the viewing window or humidity sensor, providing real-time feedback to the control panel.

Understand the functions of dehumidifiers

Manufacturers use dehumidifiers with hot air dryers to perform high-efficiency dehumidification and drying operations on highly hygroscopic engineering plastics (such as Nylon, PC, PBT, PET, etc.). Effectively remove moisture from plastic resins by combining desiccant technology and airflow systems. Desiccant materials, such as silica gel or molecular sieves, absorb moisture from the air inside the dehumidifier, reducing the relative humidity to the desired level. In this process, low-humidity air circulates through a hopper or drying chamber, where it contacts the plastic resin, absorbing moisture from the material and reducing its moisture content to the desired level.

Dehumidifier design, composition, and operation

The main components of a dehumidifier include a drying chamber, a honeycomb dehumidification wheel, a regenerative heater, a blower, and a control panel. The PID temperature control system can accurately control the regeneration temperature and ensure the stability of the dew point. In contrast, the double cooler structure can ensure lower return air temperature and dew point. A return air filter inside ensures that raw material dust does not contaminate the honeycomb runner. The silicone adsorption honeycomb dehumidification allows the regeneration temperature to be only 180°C, which is more energy-saving. The overall design structure is simple and compact, saving space and making it easy to move.

The dehumidifier loads plastic resin into the dehumidifier and then sets the drying parameters on the control panel according to specific requirements. The dehumidifier rotor continuously rotates to absorb moisture from the air inside the dehumidifier. The regenerative heater periodically heats the dehumidification wheel to remove moisture and restore its adsorption capacity. A blower or fan circulates air through the dehumidifier, ensuring the resin is exposed to dry air and effectively removing moisture from the material.

Distinguish the energy efficiency between the two

Differentiating between a dehumidifier and an injection molding hopper dryer requires energy efficiency and cost-effectiveness considerations. While both machines are designed to remove moisture from plastic resins, they employ different technologies, increasing energy consumption and operating costs. Dehumidifiers require more energy to power the desiccant rotor and the blower or fan that circulates air through the machine. While desiccant dehumidifiers have excellent moisture removal capabilities, they tend to use more energy than other drying methods. On the other hand, injection molding hopper dryers do not require energy to power heating elements and blowers or fans, so their energy consumption is generally lower.

To achieve simpler, higher efficiency and lower energy consumption, we combine the two to realize the functions of dehumidification, drying, and feeding. Using a microcomputer makes operations more straightforward, the performance more stable, and it can meet different customer needs.

injection molding hopper dryer 3


This guide introduces the differences and design components between the two. With the emergence and popularization of the automation industry, more and more people use three-in-one dehumidification dryers to work in the production line, which can save work efficiency. , making the operation easier.

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