HYDRAULICS Flashcards
Maximum power output and low mass of aeroplane hydraulics systems can be achieved with high system pressure and low volume flow
Hidrolik sistemler çok basınçlandırıp (3000 psi) az akışkan kullanıldığında yüksek gücü elde ederken hafif kalabiliyoruz.
Active system pressured by a pressure pump (engine driven)
Passive system not pressurzed by a pump
Passive (damacana pompası)
Yağ basıncını pompadan sonra ölçeriz, yağ sıcaklığını soğutucudan sonra ölçeriz
Pompanın ve soğutucunun çalıştığını kontrol etmek için.
Hydraulic fluid must have following characteristics
thermal stability
low emulsifying characteristics
Corrosion resistance
High flash and fire points
Low compressibility
Low volatility
Low viscosity
Compatible with other materials (prevents deterioration of seals and gaskets)
Volatility - uçuculuk. Çatlaklardan kaçmasın.
Bal yüksek vizkozite - su düşük vizkozite
Aviation Hydraulic fluid - phosphate ester base (purple)
Sentetik hidrolik sıvıları kavitasyon direnclidir. Deri ve gözden sakınılmalıdır.
Reservoir is a tank to supply adequate fluid to the system.
Reservoirs can be pressurized by bleed air from the engine
In a hydraulic system, the reservoir is pressurized to prevent pump cavitation
When powering up a hydraulic system, the level in the reservoir will decrease slightly
Rezervuar basınçlandırılır, bu sayede hidrolik sıvıdaki baloncukları doldurarak kavitasyonu engeller.
Hattın içi ilk başta boş, bundan dolayı sistem çalıştığında kanallar rezervuardan hidrolik sıvısı çeker.
Actuator (or Jack)
Component that converts hydraulic pressure into linear motion is called an actuator (or jack).
A single action actuator is powered with hydraulic & spring.
Accumulators
Store fluid under pressure
Provide a limited supply of pressure in an emergency
Dampen out pressure fluctiations
An energy storage
Shuttle valve
A hydraulic shuttle valve enables an alternate system to operate the same actuators in case of normal system failure
Problemli kanalı mühürleyip yedek kanaldan hidrolik sıvısını actuatore aktarıyor.
Hydraulic lock
In a typical system represented in the graphic, assuming hydraulic pressure throughout and no internal leakage a condition of hydraulic lock exist and no movement of the piston will take place
İstenilen bir durum, örneğin pilotun flapları ayarlayıp orada hidrolik kilitin kendiliğinden tutması
NonReturn Valves (check-valf)
Allow fluid in one direction.
Diyot gibi çalışır. Pompadan sonra konulur ki pompaya geri akış olmasın.
Hand pumps are used for maintenance activities such as raising brake pressure without starting the engines, opening cargo doors, and can be used for emergency power in flight
Electric pumps- electrical motor pumps are installed for use in emergencies or during ground operations
Engine driven pump (EDP)
EDPs serve as the primary hydraulic flow and pressure supply for the hydraulic users within the aircraft system. The typical EDP configuration is a pressure compansated, variable displacement axial piston pump capable of vary the volume delivered to maintain hydraulic system pressure.
AXIAL PISTON PUMPS ARE OFTEN USED IN HYDRAULIC SYSTEM DUE TO THEIR ABILITY TO PRODUCE HIGH PRESSURE WHEN REQUIRED BUT CAN BE OFF LOADED TO REDUCE POWER CONSUMPTION
IN A HYDRAULIC SYSTEM OVERHEAT DEDECTOR SARE MOSTLY INSTALLED AT THE PUMPS.
LOW PRESSURE SYSTEM PUMPS
Spur gear pumps
Centrifugal pumps
Centrifugal pumps genellikle yakıt sistemlerinde kullanılıyor.
Should a hydraulic pump seize during operation the quill drive will shear to offload and protect the gearbox.
Hidrolik sistemler çok değerli, mekanik kısımlarda herhangi bir sıkışma oluştuğunda daha büyük zarar verebilir….
Bundan dolayı quill drive denilen parça shearda kırılır ve gearbox ı korur.
