Vent Valve

Owned by Hamza Wael Abuabah, created
Last updated: Dec 29, 2021
3 min read

Component basics

Title

SRAD Pneumatically-Actuated Vent Valve

Description

An SRAD pneumatically-actuated vent valve, which allows better control over the state of the oxidizer tank during fill procedures than would be afforded with the permanent vent port used in previous iterations of the engine. It uses compressed air stored onboard the rocket to actuate a piston which opens and closes a vent port. The valve is normally open, and fails open when supply air pressure is insufficient. All components of this system are currently made from 6061-T6 aluminum, but the flight model may be fabricated from stainless steel for increased durability. This system has been successfully cold-flow tested using liquid CO2 to confirm that it actuates correctly under pressure.

Photo

 

Key components

  1. Vent Valve Body

  2. Vent Valve Piston

  3. Vent Valve Cap

 

 

Specifications

Usage

For a valve to be normally open it must be spring loaded to open, and only close when a control signal is actively applied. The spring pushes against the piston to fully open the oxidizer orfice and allow venting. The system uses an energy-efficient pneumatic system. A low-power electrical solenoid is used to allow air to go into the vent valve when a control signal is given. The air pushes on the piston on the air side, moving it to close the supply on the oxidizer side, disallowing venting.

  • Pneumatic side pressure: 150 psi MAX

  • Oxidizer side pressure: 1000 psi MAX

Usage

For a valve to be normally open it must be spring loaded to open, and only close when a control signal is actively applied. The spring pushes against the piston to fully open the oxidizer orfice and allow venting. The system uses an energy-efficient pneumatic system. A low-power electrical solenoid is used to allow air to go into the vent valve when a control signal is given. The air pushes on the piston on the air side, moving it to close the supply on the oxidizer side, disallowing venting.

  • Pneumatic side pressure: 150 psi MAX

  • Oxidizer side pressure: 1000 psi MAX

Rated Pressures

  • Pneumatic side pressure: 145 psi MAX. This is based on the highest rating on most pneumatic components, which is typically 1MPa (145psi)

  • Oxidizer side pressure: 1000 psi MAX. This is based on the highest temperature Nitrous Oxide can reach when stored in the tank

Tests Done

  • Seal strength tests with water as an analogue for Nitrous Oxide up to 1400psi of water: Vent Valve Water Testing - Google Sheets

  • Cold Flow tests. March 21st 2020. Performed with CO2 as an analogue for N2O

    • Cold flow #1: Air supply at 65 psi and CO2 cylinder at ~700psi. Actuation unsuccessful

    • Cold flow #2: Air supply at 95 psi and CO2 cylinder at ~820psi. Actuation successful + hold for 2 minute duration.

  • Static Fire 5: Performed with N2O. Successful actuation with 720psi air pressure

 

Additional guidance

Design Documentation