Level 1 Flashcards
1ft cubed = how many gallons?
7.48gal
F* to C*
F* = (1.8 × C) + 32
Absolute zero F/C
-460/-273
Density of water
62.4 lb/ftcubed
1 psi = ?inHg
2.04inHg (29.92÷14.696)
Y=
O=
C=
G=
R=
W=
Aux=
Y= compressor
O= Reversing valve
C= common
G= Fan
R= 24v power
W= call for heat
Aux= aux heat
Weight =
Mass x gravity
Specific gravity =
Density of substance/ density of water
Specific volumn of air
13.33ft3/lb
Specific volumn (ft3/lb) is the inverse of
Density (lb/ft3)
Boules law equasion
V2 = p1 x v1 / p2
Charles law equation
V2 = v1 x t2/ t1 or p2 = p1xt2/t1
What do you need to do before calculating gas laws?
Change the temp and pressure to absolute values (psia/R)
General law of perfect gas
P1xv1/t1 = p2xv2/t2
Eg p2= p1xv1xt2/ v2xt1
Work calculation
Force(lb) x distance (lb)
1hp = x watts
746 watts
1 hp = x ft-lb/min
33,000 ft-lb/min
1 hp = x btu/hr
3413 btu/h
What temp is soldering done?
Under 840*F
What temp is brazing done at?
Above 840*F
Backfire
Flame extinguisher with a loud cracking sound.
Caused by low flow pressure
Flashback
Flame begins to burn inside the tip
Shrill hissing or squealing
Caused by incorrect pressures
Carburizing flame
Excess acetylene
Deposits carbon on base metal
Blue inner core
Yellow white feather
Outer flame
Neutral flame
Equal amount of O2 and acetylene
Use for brazing
Slightly rounded, blue white inner cone
Outer flame
Oxidizing flame
Excess oxygen
Sharp pale blue inner cone
Shorter, ragged outer flame
Order to start oxyacetylene torch
Acetylene first
To close, oxygen first
Heat and torches tip relationship
Smaller tip for lower heat and smaller tubing
Larger tip for higher heat and larger tubing
Usable plug at the bottom of an acetylene tank will melt at ___*F
212F (100C)
The weight if a cylinder before refrigerant us added is called:
Tare weight
An acetylene cylinder is pressurized to ___ psi at 70*F
250 psi
A _____ is used to reduce cylinder pressure to working pressure
Pressure regulator
The working pressure that is considered normal for soldering (psi)
5 psi
The outle hose on an acetylene regulator has a special _____ threaded male fitting
Left-handed
An air-acetylene torch will reach a max temp of . . .
3600*F
High velocity tips (for brazing) require _____ psi work pressure
15 psi
A type of check valve with a built in flame arrestor that is installed in the supply hose of a torch to prevent the flame from traveling inside the hose to the supply tank
Flashback arrestor
The hardening of soft copper due to repeated bending or happering
Work hardening
Oxygen cylinders are charged to ___ psi at 70*F
2200 psi
Backfire
Improper operation of the torch tip may cause the flame to extinguish with a,loud cracking sound
