Air Turbine Starter Lubrication Recirculation for Overflow Control
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Solution Overview
Problem
Existing air turbine starters face challenges in efficiently distributing and managing lubricant, particularly in ensuring proper lubrication under varying operating conditions and preventing lubricant overflows or shortages.
Innovation Solution
The implementation of a lubrication recirculation circuit that includes a valve system to control lubricant flow between the accessory gear box and the air turbine starter, allowing for selective distribution to the turbine and drive sections based on pressure conditions, and includes a bypass mechanism to manage excess lubricant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lubrication is provided from the accessory gear box to the air turbine starter, then the internal components receive necessary lubrication, but lubricant overflow or shortage may occur under varying operating conditions
Solution Approach 1:
The patent employs a pressure-dependent valve system that dynamically adjusts lubricant flow based on operating conditions. The valve responds to pressure differential changes between the accessory gear box and air turbine starter, automatically opening or closing to maintain optimal lubricant quantity without overflow or shortage.
Solution Approach 2:
The lubrication system incorporates a feedback mechanism where the pressure differential between the accessory gear box and air turbine starter controls valve actuation. When pressure in the air turbine starter exceeds the accessory gear box pressure, the valve closes to prevent overflow; when pressure is lower, the valve opens to supply lubricant, creating a self-regulating system.
2Adaptability or versatility
If a self-contained lubrication system is used in the air turbine starter, then lubrication can be controlled independently, but the device complexity increases
Solution Approach 1:
The patent implements a self-service lubrication control system where the pressure differential automatically actuates the valve without external control mechanisms. The system serves itself by using its own operating pressure to control lubricant flow, eliminating the need for additional sensors, actuators, or control electronics that would increase complexity.
Solution Approach 2:
The pressure-dependent valve serves multiple functions: it acts as a check valve to prevent backflow, a flow control valve to regulate lubricant quantity, and a pressure equalization device. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while maintaining adaptability.
3Reliability
If lubricant flow rate is increased to ensure adequate lubrication during extended motoring, then bearing and rotating parts are protected, but lubricant overflow may occur
Solution Approach 1:
The patent applies preliminary anti-action by incorporating a check valve that prevents lubricant from flowing back into the accessory gear box when pressure in the air turbine starter exceeds the supply pressure. This preliminary protective measure counteracts the potential harmful effect of overflow before it occurs, allowing adequate lubrication flow without the risk of backflow into the reservoir.
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 ensures efficient lubrication distribution, extends the life of bearing and rotating parts by providing lubrication during extended motoring, and prevents lubricant overflows by controlling flow rates and redirecting excess lubricant back to the reservoir.
Implementation Method 1
A valve selectively opens and closes based on a pressure differential between the accessory gear box and the air turbine starter
Implementation Method 2
The internal components of the air turbine starter require lubrication
Data Source
AI summary
An air turbine starter (ATS) for a gas turbine engine having an accessory gear box (AGB) with a lubricant reservoir, the air turbine starter comprising a housing at least partially defining a working air flow path; a turbine section comprising a turbine having an output shaft and a plurality of blades circumferential spaced about the output shaft and at least partially extending into the working air flow path; a drive section having a drive shaft operably coupled to the output shaft to engage the AGB; and a lubrication recirculation circuit fluidly coupled to the lubricant reservoir.