REG NASA-LLIS-0855-2000 Lessons Learned Pneumatic System Contamination Protection.pdf

1、Best Practices Entry: Best Practice Info:a71 Committee Approval Date: 2000-04-20a71 Center Point of Contact: KSCa71 Submitted by: Wilson HarkinsSubject: Pneumatic System Contamination Protection Practice: Install filters immediately upstream of all interfaces in pneumatic systems to control dirt and

2、 water contamination.Programs that Certify Usage: This practice has been used on the Apollo, National Space Transportation System, and Pneumatic Ground Support Systems.Center to Contact for Information: KSCImplementation Method: This Lesson Learned is based on Maintainability Technique number OPS-11

3、 from NASA Technical Memorandum 4628, Recommended Techniques for Effective Maintainability.Proper use of filters, prevents contaminated gas from interfacing with component and system operation, provides the following benefits:a71 Decreased component failure caused by contamination.a71 Efficient and

4、effective means of servicing system/equipment by filter cleaning or replacement.a71 Increased system availability due to reduction in system maintenance.No matter how well a system is designed or how expensive, particulate-contaminated gas interferes Provided by IHSNot for ResaleNo reproduction or n

5、etworking permitted without license from IHS-,-,-with component and system operation. System gas must be conditioned; it must be decontaminated before it is allowed to enter a pneumatic system. The KSC design standard for pneumatic systems defines the following requirements for filters:a71 Filters s

6、hall be installed immediately upstream of all interfaces where control of particulate matter is critical and at other appropriate points as required to control particulate migration.a71 Selection of filters shall be made only after analysis of overall system performance requirements. This ensures ma

7、ximum protection of critical components and minimal performance penalty (pressure drop).a71 Filter housings and elements shall be constructed of 300 series stainless steel to reduce particulate contamination due to corrosion. Seal materials shall conform to manufacturers recommendations and the requ

8、irements specified herein. The element construction should be welded instead of soldered whenever possible to simplify cleaning. Where 300 series stainless steel is specified, type 303 and other austenitic stainless steels should be avoided whenever possible because of susceptibility to stress corro

9、sion cracking. However, overall cost should be the deciding factor.a71 Filter elements shall maintain filtering quality and not be damaged in any way when subjected to worst-case system conditions (i.e., maximum design flow rate and element clogged to its maximum design capability).Providing uncondi

10、tioned gas in a pneumatic system will have the following effects: a71 Degraded system performance because of contamination.a71 Increased maintenance cost and downtime to recover from problems induced by contamination.a71 Decreased system availability.References 1. KSC-SD-Z-0005A, Standard for Design

11、 of Pneumatic Ground Support Equipment.2. Parker-Hannifin Corp., Bulletin 0225-B1, Fluid Power.Impact of Non-Practice: System gas must be conditioned before it is allowed to enter a new system. Installing filters immediately upstream of interfaces achieves this objective and also reduces dirt and wa

12、ter contamination that can interfere with component and system operation.Related Practices: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AAdditional Info: Approval Info: a71 Approval Date: 2000-04-20a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-