In most cases, design engineers integrate check valves into their rocket engine designs. The role of seals in these vales is thus very critical in overall launch missions. Anti-blowout seals are used in check valves to retain pressurized fluid on the high pressure side while preventing blowout of the seal from the housing. Under high pressure as well as rapid change of pressure across the seal surface, retaining the seal in its housing is very challenging. Once the dynamic sealing surface of the hardware disengages from the sealing lip, there is a tendency of the seal to be blown away from the housing due to residual pressure around the seal. Normally seat seals, simple blocks of PTFE, are used in check valves but these seals’ performance are not consistent and over time, the seat seals experience permanent deformation resulting in leakage.
Saint-Gobain Seals’ anti-blowout seal, derived from their OmniSeal® 103A configuration, consists of a polymeric jacket with a spring-energizer. The jacket is made from a proprietary Fluoroloy® material while the spring can be made from materials including stainless steel and Elgiloy®. The spring can be heat treated and cleaned using special processes depending on the working condition of the check valve. An example of a general Saint-Gobain Seals’ anti-blowout seal in a rod sealing application is shown in the illustration at left (note: this illustration is different than the seal used in the actual check valve application, which is custom-designed)
The purpose of the OmniSeal® anti-blowout seal used in the check valve of the rocket engine is to seal pressurized gas and liquefied gas from temperatures below -300°F (-184°C) up to 122°F (50°C). The seal is proofed for pressure close to 3,000 psi (207 bar). The Fluoroloy® jacket material provides excellent wear resistance, anti-deformation, low coefficient of friction and very cold temperature capabilities. The OmniSeal® anti-blowout seal is designed to operate for hundreds of cycles without any leakage.
The OmniSeal® product line is available in multiple designs such as 103A, APS, Spring Ring II, 400A, RP II and RACO™ 1100A and are also offered in various custom designs. These designs include seal jackets in various Fluoroloy® materials and springs in various configurations. Saint-
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About Saint-Gobain Seals (http://www.seals.saint-
Saint-Gobain Seals is a business unit under Saint-Gobain Performance Plastics’ Engineered Components division; our parent company is one of the world’s top 100 industrial groups. With more than 50 years of manufacturing experience and an established global presence (with strategic sites in Garden Grove, California, USA; Belgium, Kontich; and Minhang, Shanghai, China), we offer a diverse range of innovative sealing and polymer solutions:
• OmniSeal® Spring–Energized Seals
• OmniLip™ PTFE Rotary Shaft Seals
• OmniFlex™ Fluoroelastomer Seals
• OmniShield® EMI / RFI Shielding Solutions
• Rulon® High-Performance Fluoropolymer Compounds
• Meldin® 7000 Thermoset Polyimide Materials
• Meldin® HT High-Performance Thermoplastic Materials
Other products include Fluoroloy® (high-performance custom-formulated compounds and alloys), cup seals, hydraulic seals, metal seals, v-packings, piston rings, Marathon® (valves and vacuum pump diaphragms), Transband® (PTFE creepage band), custom parts, polymer bearings and stock shapes.
The majority of seals and polymer components manufactured are custom designed and matched with the best materials to optimize their performance in various applications and markets.