Snow and ice removal for impinger

A method of reducing a temperature of at least one item, comprising:

• transporting the at least one item on a moving substrate within an enclosure, the enclosure comprising at least one impingement apparatus comprising:
• (a) a barrier defining a low pressure zone and a high pressure zone within the enclosure,
• (b) at least one impinger comprising openings, the at least one impinger being supported by the barrier and separating the high pressure zone from the low pressure zone, for maintaining a pressure differential between the high and low pressure zones, and
• (c) a variable-speed gas circulation device in fluid communication with the high pressure zone and the low pressure zone for maintaining a pressure of the high pressure zone, the variable-speed gas circulation device selected from the group consisting of a variable speed motor and an impeller, a blower, and an axial flow fan;
• providing a coolant to at least one of the high pressure zone or the low pressure zone;
• circulating the coolant through the high and low pressure zones using the variable-speed gas circulation device;
• directing impingement jets of the circulating coolant through the openings of the at least one impinger and toward the moving substrate;
• sensing any snow and ice accumulated on the at least one impinger;
• and
• intermittently performing an operation on the at least one impingement apparatus during said transporting, the operation comprising:
• (i) reducing a speed of the variable-speed gas circulation device for providing a decreased pressure differential between the high pressure zone and the low pressure zone,
• (ii) vibrating the at least one impinger during the decreased pressure differential for breaking up the any snow and ice accumulated on the at least one impinger and forcing some broken-up snow and ice through the openings in the at least one impinger, and
• (iii) increasing the speed of the variable-speed gas circulation device after said vibrating the at least one impinger is completed for re-establishing the pressure differential from the decreased pressure differential to be substantially similar to the pressure differential existing prior to said reducing the speed of the variable-speed gas circulation device.