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Method and Procedure to remove critical air flow blockage in a redundant Storage System Disk Drive Enclosure

IP.com Disclosure Number: IPCOM000130328D
Original Publication Date: 2005-Oct-19
Included in the Prior Art Database: 2005-Oct-19
Document File: 2 page(s) / 475K

Publishing Venue

IBM

Abstract

Method and Procedure to remove critical air flow blockage in a redundant Storage System Disk Drive Enclosure. If the airflow path is blocked by an external obstruction, e.g. paper or plastic, the airflow system can be stopped or reversed to remove the obstruction.

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Method and Procedure to remove critical air flow blockage in a redundant Storage System Disk Drive Enclosure

Storage disk drive enclosures are generally 19" rack mount systems but also include other form factors as well. The most typical packaging arrangement for disk drive enclosures is to locate the disk drives in the front of the enclosure with the power supplies, fans and electronics in the rear of the enclosure. Furthermore, forced air cooling is required which flows from the front to the rear, that is, air intake is in the front. See Figure 1.

Cooling is provided by a redundant set of fans, 2N or N+1. If any fan fails the remaining fan(s) maintain adequate cooling, generally by speeding up the operational fans. The cooling system must also account for incoming ambient air conditions or failures of the electronics whereby, temperatures, internal or external, become elevated. In these cases the fans are sped up to compensate for the increased temperatures. Thus, redundant cooling and temperature sensing/compensation contribute to making the overall cooling system robust. If for some reason the temperatures ever do go beyond limits the power system will shut down resulting in unavailability of the Storage enclosure.

However, the above does not account for nor can it adequately compensate for any significant obstruction in the airflow path. For example, should a common piece of 8.5" x 11" paper come in contact with the front of the enclosure as shown in Figure 2, the air flow will be impeded and internal temperatures will immediately rise. The temperature sensors will detect the rise and attempt to compensate by speeding up the fans. This in turn will only more firmly hold the paper against the enclosure. Temperatures will continue to rise and eventually a power shutdown will occur to prevent a hazardous...