Low-Cost, Long-Lasting Valve Seal

mechanical and fluid systems

Low-Cost, Long-Lasting Valve Seal (MFS-TOPS-71)

A simple and new valve seat installation technique for leak prevention

Overview

NASA Marshall Space Flight Center has developed a new, simplified method for installing valve seats, eliminating the need for a swaged assembly process and the additional hardware and equipment that are typically found in conventional, elastomeric valve seat installations. In addition to weight reduction, the fewer hardware components reduce the number of potential failure modes. This simplified technique saves time and installation costs, and results in comparable leakage protection by minimizing acute stress in the seal material. NASA has used the installation technique on gas-fed, pulsed, electric thrusters for propellants, which requires very specific fluid flow operation by quickly opening and closing the valves within short durations of time. The NASA technique is especially advantageous for small instrumentation valves where precise fluid control is essential.

The Technology

NASA's technique simplifies the seat installation process by requiring less installation equipment, eliminating the need for unnecessary apparatus such as fasteners and retainers. Multiple seals can be installed simultaneously, saving both time and money. NASA has tested the long-term performance of a solenoid actuated valve with a seat that was fitted using the new installation technique. The valve was fabricated and tested to determine high-cycle and internal leakage performance for an inductive pulsed plasma thruster (IPPT) application for in-space propulsion. The valve demonstrated the capability to throttle the gas flow rate while maintaining low leakage rates of less than 10-3 standard cubic centimeters per second (sccss) of helium (He) at the beginning of the valves lifetime. The IPPT solenoid actuated valve test successfully reached 1 million cycles with desirable leakage performance, which is beyond traditional solenoid valve applications requirements. Future design iterations can further enhance the valve's life span and performance. The seat seal installation method is most applicable to small valve instruments that have a small orifice of 0.5 inches or less.

Beyond aerospace applications, the seat seal technique can also be used in other applications where small instrumentation valve fluid control is required, such as medical equipment.

Benefits

Easy installation: simplifies the seat installation process
Low manufacturing costs: eliminates traditional installation equipment and steps, such as the swaged manufacturing process, saving time and money
Improved performance: reduces failure mode potential due to fewer material components while maintaining comparable or lower leakage rates
Scalable: can be scaled up to install multiple seat seals simultaneously
Lower mass: reduces payload weight

Applications

Solenoid valves
Check valves
Manual valves
Disconnects
Regulators
Relief valves

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Technology Details

Category mechanical and fluid systems

Reference Number MFS-TOPS-71

Case Number(s) MFS-33027-1

Patent(s) 10,197,165

Attachments

Papers Burkhardt, W.M., Crapuchettes, J.M., Addona, B.M., & Polzin, K.A. (2015). Development of long-lifetime pulsed gas valves for pulsed electric thrusters. 51st AIAA/SAE/ASEE Joint Propulsion Conference, Propulsion and Energy Forum, Orlando, FL.

Tags:

liquid propulsion instrument valves fluid control plunger seal install cryogenic install small dia. valve swage alternative plasma thruster solenoid valve check valve regulator valve relief valve seal failure valve leakage

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