Tenney Industrial Blast Freezer Cools Blood Plasma
A leading international manufacturer of pharmaceuticals and medical products asked TPS to design a chamber that would freeze blood plasma at a very accelerated pace while maintaining compliance with stringent international standards for Fresh Frozen Plasma, TPS answered the call by engineering a custom industrial blast freezer to meet the customer’s specific needs.
The new, Tenney Industrial Blast Freezer rapidly and safely freezes blood plasma, taking it from room temperature to -65 ⁰C in less than ten minutes. The chamber provides 12.5 cubic feet of workspace and accommodates two, stainless-steel inserts that each hold eight, 4.4-liter units of plasma, enabling the customer to freeze 16 units simultaneously. The chamber’s rapid freezing process provides temperature uniformity in every bag as well as optimal freezing efficiency, enabling the customer to transfer the freshly frozen product to a storage location and quickly begin a new processing cycle.
The blast freezer’s extremely low temperatures are attained through a cascade refrigeration system that uses two, 25-HP reciprocating compressors in a low stage/high stage design, with thermostatic expansion-valve-type refrigerant control. In the lower stage, a cascade condenser uses high-stage refrigerant to cool and condense low-stage refrigerant. A water-cooled condenser in the high stage changes hot, compressed, refrigerant gas into a liquid state to achieve specific heat-transfer functions. Cooling is accomplished though a high-volume air-delivery system and regulation of refrigerant flow to the chamber’s large evaporator-cooling coil. Four blower wheels with externally mounted motors generate the chamber’s 6,000 cubic-feet-per-minute, horizontal airflow.
Temperature conditions in the chamber are controlled by a Honeywell Model UDC3200 temperature controller and are measured using a 100-ohm, platinum resistance temperature detector housed in a stainless steel sheath. The blast freezer has an operating temperature range of -65 ⁰C to -47 ⁰C, with an accuracy of +/-1 ⁰C after stabilization. A dry-air purge system keeps the cooling coil from icing and allows the chamber to defrost to room temperature when empty.
Insulated with 6” thick rigid, foamed urethane, the chamber’s interior and exterior walls, ceiling, and floor are constructed of type 304 stainless steel. All of the blast freezer’s seems are welded or silicon-sealed to eliminate risk of moisture intrusion during long periods of operation at below freezing conditions. A mullion heater prevents the chamber door gasket from freezing.
The blast freezer is equipped with a heat limiter and over/under temperature protection as part of a comprehensive alarm and shutdown circuit that ensures the quality and integrity of the fresh frozen plasma. Other safety features include overcurrent protection on all main power circuits, redundant mechanical pressure-relief valves for each of the two refrigeration stages, a blower-motor-failure alarm system, and high- and low-process alarms. A refrigerant-gas storage tank is included to maintain proper system pressure during start-up and shutdown.
Although the industrial blast freezer was built to meet the specific requirements of the manufacturer that requested it, Tenney is able to customize the chamber to accommodate other applications, configurations, footprints, and options.
Thermal Product Solutions designs and manufactures industrial ovens, furnaces, and environmental temperature cycling and stability test chambers. Product brands include Blue M, Gruenberg, Lindberg/MPH, Tenney, and Wisconsin Oven. TPS is headquartered in New Columbia, Pennsylvania. Lindberg/MPH is located in Riverside, Michigan, and Wisconsin Oven is located in East Troy, Wisconsin. For more information, visit http://www.thermalproductsolutions.com.
