1st B Flashcards
How does a lithium bromide system work starting with the generator
Near perfect vacuum. Water as the refrigerant and bromide and absorbent.
Heat in the generator evaporates the water from the bromide.
Bromide flows to absorber, and water is condensed in the condenser then sprayed over coils in the evaporator.
As the waster evaporates it pulls heat from the water to be cooled.
What four factors determine the combustion space of a boiler
Fuel characteristics
Firing Method
steam pressure
heating capacity
How is a generator protected from a bad ground or a short
Circuit breakers, fuses, ground faults.
AC injection based protection ignores the affects of sudden DC current changes.
What determines the voltages of a DC generator
Strength of magnetic field
Number of conductors cutting this field
Speed of rotation
How is electricity produced in the generator
Generator uses a magnetic field created by coils and the electric pressure created in a conductor that is cutting through the magnetic field to create voltage.
Define rupture disk
Prebulged membrane
Turbine exhaust in case the condenser losses vacuum
What could cause a turbine to be noisy
Unbalanced rotating parts
Misaligned or bent shaft
Moisture in the steam
Loose bearings
Overheating
Worn parts
List six ways to test steam traps
Temp difference in & out
Listening device
Temp crayons
Flow indicator
Test valves
Knowledge of equipment
Electrical drawing
Line above two circles
normal closed
Electrical drawing
Line below two circles
Normal open
What items would be listed on an EPA refrigerant compliance program checklist
All owners/operators of equipment containing over 50 pounds of refrigerant must:
-Keep records of refrigerant and service performed
-Understand updated regulations and policies
-Written mission statement for compliance
-Written job description for someone trained in refrigeration
-Copies of EPA certs
-Written storage and inventory policy
-Written leak test policy
-Response plan for accidents
What are slip ring motors used for
Give 4 examples
Starting current of the equipment under full load would be excessive
Compressors, loaded conveyors, mixers, grinders
-
Name and explain the auxiliary device necessary for startup on a DC motor
Starting rheostat or a starting box with considerable resistance is connected to the circuit to reduced the current going to the motor.
As it gains speed the rheostat increases the voltage until full speed is attained.
How does an evaporator condenser work
-steam coil in a tank
-water is fed to the tanks and it boils
-cool condensate runs through the coils to condense the vapor, producing distilled water
Who can inspect and repair your UST leak detection and overfill protection systems?
List six things to log on the report
-Qualified UST inspector/contractor
-Identify equipment
-Release detection
-suspect or confirmed releases
-spill & overfill protection
-corrision protection
-walk through inspection
Tenacity
resist pulling stress
Ductility
Endure elongation
Malleability
Change shape by hammering
Elastcity
Resume normal shape
resilience
storage and return of work energy while being stressed to its elastic limits
hardness
resist wear
What is pressure stage of turbine
Allows only a limited pressure drop in ones set of nozzles
What is velocity stage of turbine
Applying velocity energy in the steam coming from nozzles to two or more sets of moving blades
What is the difference between pressure and velocity stage of turbines
Difference is where the pressure drops occur
What is the difference between an impulse and reaction turbine
Impulse- expansion of the steam occurs almost entirely in its stationary blades
Reaction- Expansion of the steam occurs in the rotating blades
Name four kinds of impulse turbines
-re-entry flow
-rotor
-vertical
-horizontal
Name four kinds of reaction turbines
-tandem
-single flow
-double flow
-parsons
List five EPA responsibilites
-establish and enforce regulation
-offer grants
-study issues affecting the environment
-teach others about the environment
-assist homeland security
Name 3 types of coal mills
Ball
Bowl
Hammer
Describe ball mill
Consists of a rotating cylinder or tube containing steel balls. Coal is introduced into the tube and tumbling steel balls crush it to powder.
Describe bowl mill
Uses heavy rollers which run against a steel ring or bowl. Coal in introduced into the bowl and is crushed between bowl and rollers.
Describe hammer mill
Uses hinged hammers to crush the coal against a steel striking plate
What steam condition is a reaction turbine best suited for
Low to medium head applications and high flow rates
Falling film evaporator
a liquid film flows down a heated vertical tube
Rising film evaporator
the rising film allows the liquid to rise as a vapor forms
Plate evaporator
It uses multiple plates with a large surface area for heat transfer.
What is the purpose of the equalizer in a boiler?
Balances the pressure between the boiler’s steam outlet and condensate return inlet
What is a waste heat boiler
A waste heat boiler uses the heat formed as a byproduct of another process, heat which would
normally be wasted, and uses it to create steam.
