In the production of medical devices and plastic pharmaceutical packaging, granule dehumidification must meet stricter requirements than in other fields. Let’s look at these requirements and how Vismec’s cleanroom rotary dryers can meet them.

Why do the medical and pharmaceutical industries have specific plastic dehumidification requirements?

Many hygroscopic engineering polymers, such as PC, PA, and PET, require thorough dehumidification before processing. In fact, excessive residual moisture in the pellets can cause surface defects, streaking, bubble formation and, in hydrolysis-sensitive materials, a deterioration in the mechanical properties of the finished product.

In plastic injection molding, these issues can compromise the quality of the finished product. Furthermore, in the medical and pharmaceutical sectors, they can also pose a compliance issue with regard to the required technical and quality standards.

In these sectors, polymer processing may take place in cleanrooms or controlled environments, where all equipment used in the production process must meet specific cleanliness and contamination control requirements to prevent particles or other contaminants from entering the production environment.

Besides, two requirements are typical of regulated manufacturing: traceability of process parameters, batch by batch, and repeatability of results over time.

 

Characteristics of a dryer for the medical sector

In summary, an industrial dehumidifier intended for these sectors must meet at least three requirements, which we will discuss below.

• Materials suitable for controlled environments: parts in contact with the process air and the material must be made of durable, easy-to-clean materials, such as stainless steel, to minimize the risk of contamination.
• Stable and measurable dew point: the dew point of the dry air must remain constant throughout the entire production process and be continuously monitored to ensure that each batch of granules is processed under the same conditions.
• Data monitoring and logging: temperatures, flow rates, and loading cycles must be monitored and, if required, documented as part of the company’s quality management system.

 

The cleanroom version of Vismec’s desiccant wheel dehumidifiers

Among Vismec models, rotary dryers in the Drywell (DW) and Dryplus (DP) series, there are options specifically designed for cleanrooms and medical and pharmaceutical applications.

The basis remains rotor technology: the pure molecular sieve is applied to a synthetic honeycomb substrate, and the rotor is driven by a stepper motor through three processes: dehumidification, regeneration, and cooling.

The DW and DP series guarantee a dew point that is constant and adjustable down to -50 °C, with dehumidification temperatures up to 180 °C.

What is the cleanroom version of a dryer?

The cleanroom version of a dehumidifier is constructed with materials and components suitable for controlled environments. The Vismec medical line is based on standard DW dehumidifiers and can be installed directly in cleanrooms.

DW dehumidifiers are mounted on the hopper, reducing the floor space they occupy. Furthermore, the DW and DP models do not require compressed air or cooling water, nor the associated connections.

Materials and components: stainless steel, filters, and dew point probe

Compared to the standard version, the DW medical line stands out for:

• a stainless steel hopper, fully insulated, with a stainless steel finish both inside and outside;
• stainless steel air filter and air ducts;
• a dew point sensor already included as standard, to monitor the quality of the dry air supplied to the material.

Among the accessories, the Vismec 50 Oil Trap is an oil separator suitable for medical and pharmaceutical applications: it condenses at least 98% of the oils and, with the optional two-stage filtration system, removes up to 99.99% of them.

Advantages for companies: precision, traceability, process control

The DW and DP dehumidifiers, together with accessories and monitoring systems, offer several advantages to plastic processing companies operating in the medical and pharmaceutical sectors.

Constant dew point and data logging

A stable dew point means the pellets are conditioned in the same way in every cycle.

This parameter can be monitored using the portable dew point meter with a data logger. It records the dew point trends over the desired period, triggers an alarm if the set threshold is exceeded, and allows you to save the data to a USB flash drive for archiving in the quality management system.

Process control is enhanced by three functions available on Vismec dehumidifiers. Let’s take a look at them.

• SLS (Safety Loading System): by monitoring the dehumidification time, it prevents non-dehumidified material from reaching the production machinery.
• MPM (Material Protection Management): protects the polymer from over-dehumidification and degradation by monitoring the loading system or the return air temperature.
• Table of materials: allows you to select materials and recall preset or programmable dehumidification parameters. 

Cycle monitoring with HALO and Industry 4.0 supervision

Connected to the dryer, the HALO weighing ring measures the flow rate in kg/h and the quantity of loaded material in real time, displaying the last five loading cycles.

The total weight can be reset to zero when a new batch begins, and if production exceeds the capacity of the dehumidifier-hopper combination, an alert is triggered.

Finally, thanks to the Vismec supervision system, the data can be accessed from a PC, tablet, or smartphone. Furthermore, the OPC UA protocol integrated into the new supervisor improves connectivity with the management software used in the company, while alarms allow operators to identify the location and time of each anomaly. 

Together, these tools support the traceability and repeatability required in regulated sectors such as the medical or pharmaceutical industries

Does your company process granules to produce plastics for the medical or pharmaceutical sector and require controlled and precise dehumidification in a cleanroom? Contact Vismec for a consultation and a customized quote.