BACKGROUND

In the transport of pharmaceutical and other temperature sensitive products such as vaccines and the like, special multi-walled packaging or shipping containers may be used in which gel packs are arranged about inner boxes or the like of the packaging. The gel packs provide a thermal battery to absorb or release heat during the transit of the packaging that otherwise may become exposed to ambient hot or cold temperatures depending on geographic region of the shipment and season thereof.

Gel packs are typically filled with water, phase change material (PCM), or other fluids and may be conditioned (frozen, cooled, heated) to a pre-determined temperature and stabilized at the pre-determined temperature before use. A phase change material (PCM) is a substance with a high heat of fusion which, melting and solidifying at a certain temperature, is capable of storing and releasing large amounts of energy.

Packaging and shipment of different pharmaceutical products may require gel packs conditioned and stabilized at a variety of different temperatures. In addition, gel packs conditioned at different temperatures may be used within the same packaging at different locations within the packaging. By way of example and not by way of limitation, packaging may require, for instance, the use of gel packs frozen at −20° C. (−4° F.) arranged at some locations within the packaging and gel packs refrigerated at +5° C. (41° F.) arranged at other locations within the packaging.

For purposes of assuring proper performance of such packaging, it is imperative to prepare the material within the gel packs to be solid, liquid, or a mixture of part solid and part liquid and at a specific desired temperature to assure a range of internal enthalpy (internal energy related to sensible and latent heat) of the gel pack. The packaging must perform similar to tests performed during the qualification of the packaging and process of preparing and assembling the packaging with conditioned and stabilized gel packs.

Standalone equipment or walk-in areas maintained at controlled temperatures may be used to condition gel packs. For example, gel packs may be frozen in freezer units at very low temperatures (i.e., below 0° C. (32° F.)), cooled in refrigerator units at relatively cool temperatures (i. e., about +2 to +8° C. (35.6 to 46.4° F.), and/or warmed or heated in incubator units or ambient areas (i. e., for temperatures from +15 to +30° C. (59 to 86° F.)). Typically, the gel packs are permitted to remain at any of the above referenced areas for predetermined and extended periods of time to condition the gel packs and prepare the gel packs for use in shipment packaging. Depending upon the equipment used and the gel pack to be conditioned, conditioning times required to stabilize the temperature of the gel packs can require, for instance, as many as five days.

By way of further specific examples, PCM gel packs needed for ambient shipments may be conditioned by being maintained at an ambient temperature for at least 24 hours to stabilize the temperature of the gel packs before use. PCM gel packs needed for refrigerated shipments may be conditioned by being frozen in a freezer for 24 hours and then placed in a refrigerator (at a temperature slightly below freezing) for at least 24 hours to stabilize the temperature of the gel packs before use (i.e., for 48 total hours of conditioning). PCM gel packs needed for frozen shipments and water-based gel packs needed for refrigerated shipments may be conditioned by being frozen in a freezer for 72 hours to stabilize the temperature of the gel packs before use. For some larger scale conditioning operations, an additional 4 to 24 hours of pre-cooling in a freezer or blast freezer (i.e., a freezer in which cold air is circulated by blowers) may be added to the above conditioning times.

SUMMARY

According to an embodiment, automated blast gel pack conditioning equipment is provided. The conditioning equipment includes a housing with an evaporator and heater for defining a void space for containing a set of gel packs, at least one fan for circulating air within the housing such that a path of air flow extends through an air insufflation end to an air return end, at least one temperature sensor located within the housing, and a controller for receiving temperature measurements from the at least one temperature sensor and for automatically controlling operation of the evaporator, heater, and fans during phase change processing (i.e., freezing or melting) and conditioning of gel packs.

According to another embodiment, a temperature sensor for PCM gel pack conditioning equipment is provided. The sensor includes a pot-shaped container filled with paraffin with a temperature sensor positioned against an inner wall of the pot-shaped container on an outer periphery of the paraffin.

According to a further embodiment, a method of automatically phase change processing (i.e., freezing or melting) and conditioning gel packs is provided. The method includes the steps of phase change processing a set of gel packs within blast gel pack conditioning equipment and, immediately following the phase change processing step without removing the set of gel packs from the blast gel pack conditioning equipment, conditioning the set of gel packs to a pre-determined specific temperature in order to adjust the sensible heat. The blast gel pack conditioning equipment includes a housing with an evaporator and heater, at least one fan for circulating air within the housing such that a path of air flow extends through an air insufflation end to an air return end, at least one temperature sensor located within the housing, and a controller for automatically receiving temperature measurements from the at least one temperature sensor and for automatically controlling operation of the evaporator, heater, and fans within the housing during the phase change processing and conditioning steps.

