190105cA truck/tractor air brake system components - part A Flashcards
what’s the purpose of a dual air brake system?
pg.2
greater safety incase one service circuit false
pg.2
witch supply tank operates steering axle and witch operates drive axle?
pg.2
primary circuit operates = drive axle(s)
secondary circuit operates = steer axle
pg.2
what are the 5 basic circuits? name there colors
pg.2
- supply [blue]
- primary [green]
- secondary [red]
- parking/emergency brake circuit [orange]
- trailer control circuit [unknown]
pg. 2
what’s the purpose of the supply circuit?
pg.3
- provide brakes and accessories with clean dry air
- maintain system pressure
pg. 3
what are the components in a the supply circuit
pg.3
- compressor
- posture and contamination control
- reservoirs
- governor
pg. 3
what are 2 common types of compressors?
what is the more common type of driving an air compressor?
compressor output unit is___
pg.4
- single stage
- reciprocating type
- gear drive
- cfm
pg. 4
what are the 2 valves and 1 piston i need to remember from the compressor?
pg.5
- discharge valve
- inlet valve
- unloader piston/plunger
pg. 5
compressor has 2 cycles, what are they?
pg.6
- unloaded cycle
- loaded cycle
pg. 6
compressor kick out pressure is?
compressor kick in pressure is?
pg.8, 12
115 - 135 psi
25 psi less then kick out
pg.8, 12
governor pressure adjusting spring, adjusting screw and locknut is to adjust what?
pg.9
kick out pressure
pg.9
what’s the 3 ports in a compressor governor?
pg.9
- exhaust (EXH)
- unloader (UNL)
- reservoir (RES)
pg. 9
water and oil in the system causes what?
pg.12
- in the winter water freezes and causes brake malfunctions
- water and oil mix, creating slush, causing valves to stick
pg. 12
what material is inside an air dryer cartridge? and what do they do with moisture?
pg.19
desiccant material and they suspend moisture and moisture vapour
pg.19
acronym for supply port and delivery port
pg.19
- SUP (supply port)
- DEL (delivery port)
pg. 19
how big most the reservoirs be?
pg.20
atlas 12 times the combined volume of the brake chamber on the unit
pg.20
pressure reservoirs must be hydrostatically tested to _____
pg.20
5 times the related working pressure
pg.20
what is the purpose of a supply reservoir?
pg.23
- supply additional air volume
- be a final place for moisture to settle
pg. 23
purpose of a check valve at primary and secondary resevoirs?
pg.23
ensures at least one service reservoir remains charged in the even that the other loses air pressure
pg.23
what’s the safety valve for?
where can it be located?
at what pressure does the safety valve vent at?
how do you check safety valve operations?
pg.24
- incase the governor fails it prevents the system from over pressurizing
- compressor, air dryer and supply reservoir (most common)
- 150 psi
- pull on the pin
pg. 23
what type of gauge is used to determine reservoirs pressure?
witch reservoirs need a pressure gauge?
pg.25
- dual-needle pressure gauge
- primary res and secondary res
pg. 25
how does a low pressure warning device work?
pg.26
when pressure drops in the primary and/or secondary to 60 or less a visual and audible devise warns the driver.
(now a days it goes off at 68-74 psi)
pg.26
what size must tubing, hoses and fitting can they be replaced with? what type of threads are most common?
pg.27
THE SAME SIEZE. NPT
pg.27
what are air lines more commonly made of?
pg.28
nylon tubing
pg.28
where can nylon tubing not be used?
pg.28
- where heat is above 93 C
compressor discharge
- high wear, abrasion or movement is encountered
vehicle frame to brake chambers
pg.28when talking about air brakes, what type of connection is more popular for steel tubing? why?
pg.29
compression fittings, because flared connections are susceptible to fatigue from vibration
pg.29
flexible hose is used for?
pg.29
used to connect brake chambers
pg.29
what type of hose is used for compressor discharge lines?
pg.29
hoses with extruded teflon inner cores and outer stainless steel braid
pg.29
what’s the purpose of the primary service brake circuit?
pg.30
to allow the operator to control the application and release of the drive axle rakes
pg.30
primary service circuit consist of what components?
pg.31
- dual-circuit brake valves
- relay valve
- service brake chambers
pg. 31
purpose of the dual-circuit brake valve
pg.32
give the operator control of the brakes on the vehicle
pg.32
3 things that brake valve allows the operator to do is?
pg.32
- apply the brakes
- release the brakes
- regulate brake application
pg. 32
types of dual circuit brake valves
pg.32
- treadle valve (floor mounted)
- pedal valve ( firewall mounted)
pg. 32
what type of air does the dual-circuit brake valve deliver?
pg.34
signal air to the service relay
pg.34
when the dual-circuit brake valve is released, applied and balanced. what are the inlet and exhaust ports doing?
pg.36
released = inlet CLOSED and exhaust OPEN
applied = inlet OPEN and exhaust CLOSED
balanced = inlet CLOSED and exhaust CLOSED
pg.36
whats the purpose of the service relay valve and where would it be located?
pg.38
- the purpose is to speed up application and release time.
- it’s located near the primary service brake chambers
pg. 38
how does the service relay work?
pg.38
- air volume will be supplied from the primary reservoir to the supply port of the service port
- a signal line from the dual-circuit valve will connect to the control port of the service relay. this signal will activate the service relay
small air amount controlling large air amount
pg.38
the amount of air that is required to get the relay valve piston to move downwards, close the exhaust valve and open the inlet valve is called?
pg.41
cracking pressure
pg.41
what’s the function of the service brake chamber?
shortly describe it it works?
pg.44
- to convert the energy of the compressed air into mechanical energy.
- compressed air enters and pushes on the diaphragm tp apply the brakes
- the return spring on the brake shoes and the return inside the brake chamber return the pushrod
pg. 44
whats the purpose of the secondary service circuit?
pg.46
to allow the operator to control the application and release of the steer axle brakes
pg.47
what’s included in the secondary service circuit components?
pg.47
- dual-circuit brake valve
- quick release valve
- modulator valve
- steer axle service brake chambers
pg. 47
