FREE AVIATION STUDY: Engineering functions
Youneed to be able to identi...: Engineering functions You need to be able to identify the various functions within an engineering company. These include both commerci...
Saturday, July 4, 2015
FREE AVIATION STUDY: TYPES/VARIATIONS
FREE AVIATION STUDY: TYPES/VARIATIONS: TYPES/VARIATIONS Following design features and maintenance practices uphold the hydraulic system safety: (1) Design features and provisi...
FREE AVIATION STUDY: PRESSURE REGULATION
FREE AVIATION STUDY: PRESSURE REGULATION: PRESSURE REGULATION Hydraulic pressure must be regulated in order to use it to perform the desired tasks safely. Pressure regulating sys...
FREE AVIATION STUDY: HYDRAULIC FILTERS
FREE AVIATION STUDY: HYDRAULIC FILTERS: HYDRAULIC FILTERS A filter is a screening or straining device used to'-clean the hydraulic fluid, thus preventing foreign particles...
FREE AVIATION STUDY: HYDRAULIC FILTERS
FREE AVIATION STUDY: HYDRAULIC FILTERS: HYDRAULIC FILTERS A filter is a screening or straining device used to'-clean the hydraulic fluid, thus preventing foreign particles...
FREE AVIATION STUDY: CONTAMINATION CONTROL
FREE AVIATION STUDY: CONTAMINATION CONTROL: CONTAMINATION CONTROL Filters provide adequate control of the contamination problem during all normal hydraulic system operations. Contr...
CONTAMINATION CONTROL
CONTAMINATION CONTROL
Filters provide adequate control of the contamination problem during all normal hydraulic system operations. Control of the size and amount of contamination entering the system from any other source is the responsibility of the people who service and maintain the equipment. Therefore, precautions should be taken to minimize contamination during maintenance, repair, and service operations. Should the system become contaminated, the filter element should be removed and cleaned or replaced. As an aid in controlling contamination, the following maintenance and servicing procedures should be followed at all times: (1) Maintain all tools and the work area (workbenches and test equipment) in a clean, dirt-free condition. (2) A suitable container should always be provided to receive the hydraulic liquid that is spilled during component removal or disassembly procedures. (3) Before disconnecting hydraulic lines or fittings, clean the affected area with dry cleaning solvent. (4) All hydraulic lines and fittings should be capped or plugged immediately after disconnecting. (S) Before assembly of any hydraulic components, wash all parts in an approved dry cleaning solvent. (6) After cleaning the parts in the dry cleaning solution, dry the parts thoroughly and lubricate them with the recommended preservative or hydraulic liquid before assembly. Use only clean, lint-free cloths to wipe or dry the component parts. (7) All seals and gaskets should be replaced during the re-assembly procedure. Use only those seals and gaskets recommended by the manufacturer. (8) All parts should be connected with care to avoid stripping metal' slivers from threaded areas. All fittings and lines should be installed and torqued in accordance with applicable technical instructions. (9) All hydraulic servicing equipment should be kept clean and in good operating condition.
Filters provide adequate control of the contamination problem during all normal hydraulic system operations. Control of the size and amount of contamination entering the system from any other source is the responsibility of the people who service and maintain the equipment. Therefore, precautions should be taken to minimize contamination during maintenance, repair, and service operations. Should the system become contaminated, the filter element should be removed and cleaned or replaced. As an aid in controlling contamination, the following maintenance and servicing procedures should be followed at all times: (1) Maintain all tools and the work area (workbenches and test equipment) in a clean, dirt-free condition. (2) A suitable container should always be provided to receive the hydraulic liquid that is spilled during component removal or disassembly procedures. (3) Before disconnecting hydraulic lines or fittings, clean the affected area with dry cleaning solvent. (4) All hydraulic lines and fittings should be capped or plugged immediately after disconnecting. (S) Before assembly of any hydraulic components, wash all parts in an approved dry cleaning solvent. (6) After cleaning the parts in the dry cleaning solution, dry the parts thoroughly and lubricate them with the recommended preservative or hydraulic liquid before assembly. Use only clean, lint-free cloths to wipe or dry the component parts. (7) All seals and gaskets should be replaced during the re-assembly procedure. Use only those seals and gaskets recommended by the manufacturer. (8) All parts should be connected with care to avoid stripping metal' slivers from threaded areas. All fittings and lines should be installed and torqued in accordance with applicable technical instructions. (9) All hydraulic servicing equipment should be kept clean and in good operating condition.
HYDRAULIC FILTERS
HYDRAULIC FILTERS
A filter is a screening or straining device used to'-clean the hydraulic fluid, thus preventing foreign particles thus preventing contaminating substances from remaining in the system. If such objectionable material is not removed, it may cause the entire hydraulic system of the aircraft to fail through the breakdown or malfunctioning of a single unit of the system. The hydraulic fluid holds in suspension tiny particles of metal that are deposited during the normal wear of selector valves, pumps, and other system components. Such minute particles of metal may injure the units and parts through which they pass if they are not removed by a filter. Since tolerances within the hydraulic system components are quite small, it is apparent that the reliability and efficiency of the entire system depends upon adequate filtering. Filters may be located within the reservoir, in the pressure line, in the return line, or in any other location where the designer of the system decides that they are needed to safeguard the hydraulic system against impurities. There are many models and styles of filters. Their position in the aircraft and design requirements determine their shape and size. Most filters used in modern aircraft are of the inline type. The inline filter assembly is comprised of three basic units; head assembly, bowl, and element. The head assembly is that part which is secured to the aircraft structure and connecting lines. Within the head there is a bypass valve which routes the hydraulic fluid directly from the inlet to the outlet port if the filter element becomes clogged with foreign matter. The bowl is the housing which holds the element to the filter head and is that part which is removed when element removal is required. The element may be either a micronic, porous metal, or magnetic type. The micronic element is made of 7μ specially treated paper and is normally thrown away when removed. The porous metal and magnetic filter elements are designed to be cleaned by various methods and replaced in the system.
A filter is a screening or straining device used to'-clean the hydraulic fluid, thus preventing foreign particles thus preventing contaminating substances from remaining in the system. If such objectionable material is not removed, it may cause the entire hydraulic system of the aircraft to fail through the breakdown or malfunctioning of a single unit of the system. The hydraulic fluid holds in suspension tiny particles of metal that are deposited during the normal wear of selector valves, pumps, and other system components. Such minute particles of metal may injure the units and parts through which they pass if they are not removed by a filter. Since tolerances within the hydraulic system components are quite small, it is apparent that the reliability and efficiency of the entire system depends upon adequate filtering. Filters may be located within the reservoir, in the pressure line, in the return line, or in any other location where the designer of the system decides that they are needed to safeguard the hydraulic system against impurities. There are many models and styles of filters. Their position in the aircraft and design requirements determine their shape and size. Most filters used in modern aircraft are of the inline type. The inline filter assembly is comprised of three basic units; head assembly, bowl, and element. The head assembly is that part which is secured to the aircraft structure and connecting lines. Within the head there is a bypass valve which routes the hydraulic fluid directly from the inlet to the outlet port if the filter element becomes clogged with foreign matter. The bowl is the housing which holds the element to the filter head and is that part which is removed when element removal is required. The element may be either a micronic, porous metal, or magnetic type. The micronic element is made of 7μ specially treated paper and is normally thrown away when removed. The porous metal and magnetic filter elements are designed to be cleaned by various methods and replaced in the system.
PRESSURE REGULATION
PRESSURE REGULATION
Hydraulic pressure must be regulated in order to use it to perform the desired tasks safely. Pressure regulating systems will always use three elemental devices; a pressure relief valve, a pressure regulator and a pressure gage. 1.5.2 Pressure Relief Valves: A pressure relief valve is used to limit the amount of pressure being exerted on a confined liquid. This is necessary to prevent failure of components or rupture of hydraulic lines under excessive pressures. The pressure relief valve is, in effect, a system safety valve. The design of pressure relief valves incorporates adjustable spring-loaded valves. They are installed in such a manner as to discharge fluid from the pressure line into a reservoir return line when the pressure exceeds the predetermined maximum for which the valve is adjusted. Various makes and designs of pressure relief valves are in use, but, in general, they all employ a spring-loaded valuing device operated by hydraulic pressure and spring tension. Pressure relief valves are adjusted by increasing or decreasing the tension on the spring to determine the pressure required to open the valve. Two general forms of pressure relief valves, the twoport and the four-port
Hydraulic pressure must be regulated in order to use it to perform the desired tasks safely. Pressure regulating systems will always use three elemental devices; a pressure relief valve, a pressure regulator and a pressure gage. 1.5.2 Pressure Relief Valves: A pressure relief valve is used to limit the amount of pressure being exerted on a confined liquid. This is necessary to prevent failure of components or rupture of hydraulic lines under excessive pressures. The pressure relief valve is, in effect, a system safety valve. The design of pressure relief valves incorporates adjustable spring-loaded valves. They are installed in such a manner as to discharge fluid from the pressure line into a reservoir return line when the pressure exceeds the predetermined maximum for which the valve is adjusted. Various makes and designs of pressure relief valves are in use, but, in general, they all employ a spring-loaded valuing device operated by hydraulic pressure and spring tension. Pressure relief valves are adjusted by increasing or decreasing the tension on the spring to determine the pressure required to open the valve. Two general forms of pressure relief valves, the twoport and the four-port
TYPES/VARIATIONS
TYPES/VARIATIONS
Following design features and maintenance practices uphold the hydraulic system safety: (1) Design features and provisions - Failsafe design philosophy - Having safety components in the system design: Hydraulic Fuses, Priority valves, Relief Valves/Overpressure safety valves, Filters, Chip detectors (2) Preventive maintenances
FAIL SAFE DESIGN
Fail-safe design is the characteristic of almost every system of aircraft. Hydraulic failsafe is achieved by installation of following components/features: o Duplication/Triplication of the complete systems (coded as Blue, Green and Yellow hydraulic system). Each flying control is powered by at three systems independently. o Use of components like hydraulic fuse that stops fluid flow upstream incase of excessive fluid leakage down stream. o Components like accumulators can store pressure and drive components incase of failure of main pumps or engines. o Duplication/Triplication of powering units like, engine driven pumps, electric motor pumps, PTUs, hand pumps, RAT (ram air turbines) so that power can be sustained in spite of failure of the main powering devices or EDPs.
Following design features and maintenance practices uphold the hydraulic system safety: (1) Design features and provisions - Failsafe design philosophy - Having safety components in the system design: Hydraulic Fuses, Priority valves, Relief Valves/Overpressure safety valves, Filters, Chip detectors (2) Preventive maintenances
FAIL SAFE DESIGN
Fail-safe design is the characteristic of almost every system of aircraft. Hydraulic failsafe is achieved by installation of following components/features: o Duplication/Triplication of the complete systems (coded as Blue, Green and Yellow hydraulic system). Each flying control is powered by at three systems independently. o Use of components like hydraulic fuse that stops fluid flow upstream incase of excessive fluid leakage down stream. o Components like accumulators can store pressure and drive components incase of failure of main pumps or engines. o Duplication/Triplication of powering units like, engine driven pumps, electric motor pumps, PTUs, hand pumps, RAT (ram air turbines) so that power can be sustained in spite of failure of the main powering devices or EDPs.
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