Mechanical Signal Processing Accumulator Attenuation Device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current pressure sensing systems in rocket propulsion vehicles face issues with liquid ingestion into pneumatic pressure sensing lines due to pressure fluctuations, leading to erroneous propellant level measurements and potential engine shutdown, especially in extreme conditions like launch.
Innovation Solution
A passive mechanical signal processing accumulator attenuation device is used, which includes an inner container and outer thermal housing to isolate the pressure measurement location, utilizing an inertia-tube and sensing chamber to accumulate and attenuate liquid pressure surges, preventing liquid ingestion and filtering out specific frequency disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensing lines are used to measure propellant levels, then propellant quantity can be monitored, but liquid ingestion into the sensing lines occurs during pressure fluctuations causing erroneous measurements
Solution Approach 1:
A mechanical filter assembly is introduced as an intermediary component between the pressure sensing line and the propellant tank. This filter assembly includes a housing with a porous bottom wall that allows liquid propellant to pass through while blocking larger particles and debris, thereby preventing liquid ingestion into the sensing line while maintaining accurate pressure measurements
Solution Approach 2:
The filter assembly utilizes a porous bottom wall made of sintered material or mesh screen that permits fluid passage while filtering out contaminants. This porous structure allows the pressure sensing system to obtain accurate readings by letting liquid propellant flow through while blocking particles that could cause erroneous measurements or clog the sensing line
2Productivity
If the propellant tank is pressurized to maintain flow, then propellant delivery is ensured, but pressure fluctuations cause liquid to be forced into sensing lines
Solution Approach 1:
The mechanical filter assembly serves as a protective intermediary that withstands pressure fluctuations from the pressurized propellant tank. The robust housing and filtered outlet prevent pressure-induced liquid surges from entering the sensing line, allowing the tank to maintain high pressure for efficient propellant delivery without causing liquid ingestion
Solution Approach 2:
The filter assembly is installed in advance in the propellant delivery path to cushion against pressure fluctuations before they can force liquid into the sensing line. The porous filter structure and housing design absorb and dampen pressure surges, preventing them from reaching the sensing line during tank pressurization events
3Reliability
If purge gas is used to prevent liquid entry into sensing lines, then liquid ingestion is reduced, but pressure build-up can occur in the sensing line
Solution Approach 1:
The mechanical filter assembly extracts and removes liquid propellant from the gas phase in the sensing line before it can cause pressure build-up. By providing a dedicated filtered outlet for liquid removal, the system maintains sensing line integrity and prevents excessive pressure accumulation while still using purge gas to maintain reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides accurate pressure readings by preventing liquid ingestion and filtering out noise, ensuring precise propellant level monitoring and maintaining vehicle performance during launch and flight.
Implementation Method 1
the inertia-tube provides inertia impedance (inertance and resistance) to dampen energy transfer associated with liquid motion due to pressure pulses from the tank
Implementation Method 2
the inertia-tube provides inertia impedance (inertance and resistance) to dampen energy transfer associated with liquid motion due to pressure pulses from the tank
Implementation Method 3
A vent port is formed on the inner container and enables the purge gas to escape thereby enabling the sensing chamber to be maintained at a desired equilibrated pressure
Implementation Method 4
Other mechanical filtering elements may be attached to the device enabling the device to filter targeted pressure signal frequencies to further improve pressure reading capabilities
Data Source
AI summary
A liquid/gas interface pressure accumulator and mechanical filter device is especially adapted for use within a propellant utilization monitoring system of a space launch vehicle. The device provides a retrofit solution for overcoming problems associated with liquid entering a pressure sensing lines and pressure noises that collectively harm the ability to accurately measure fuel and oxidizer levels. One device is attached to each fuel and oxidizer tank of the launch vehicle. Each device includes a housing and an internal sensing chamber that is used to accumulate liquid before it can enter a pressure sensing communication line connected to a pressure sensing transducer. The construction of the device also allows filtering of undesirable pressure noises due to vibration, pressure pulsations, and other vibratory events that occur during operation of the space vehicle. The device is also selectively tunable to filter out certain frequencies and frequency ranges/bands. The invention in other aspects includes methods of improving pressure sensing applications in a propellant utilization monitoring system.