Download DC Third Class Stationary Boiler Exam 2025-2026 Latest Prep With Actual Questions and Corr and more Exams Mechanical Engineering in PDF only on Docsity!
DC Third Class Stationary Boiler Exam 2025- 2026
Latest Prep With Actual Questions and Correct
Answers/ DC Boiler Exam 2025| DC 3rd Class
Stationary Boiler 2025 - 2026 (Brand New!)
What is the thermal efficiency percentage of boiler with a stack temperature of 600 F and furnace temperature of 2800 F?
What is the proper order of zeolite rejuvenation water softener. Back Wash, Brine, Rinse , and Service given the three phase 480 - volt motor has a current draw of 42amps and a power factor rating of 90% 181 a four-wire wye-connected system with a phase-to-phase voltage of 208 volt has a volta has a phase to neutral voltage of 120 volts 120 volts steam (High Velocity) what kind of energy? Mechanical
Which of the following statement is not ture concerning a superheat? Super Heater (BTU) The ______ pump supplies the water to the condenser to condense the steam. Condensate What is the first thing that happen for a three-element regulator to change the output of the controller? Condensate Flow Increases The primary reason for using wet scrubbers is to? Remove flue gas particulates What is used on the outer rim of the blades or nozzles to stiffen the blade against vibration and confine the steam to the ________? Shroud Ring The refrigerant in a condenser to usually sub cooled between _________ degree F below the condensing temperature? .7 to 9 degrees
which of the following types of boiler is more suited for pressure exceeding 350 psi? Scotch Marine An automatic control valve commonly used to maintain feed water level in a boiler whose internal design is constructed with 2 valve and? balancing valve what are the 2 chief heat producing elements? carbon and hydrogen copper testing is used to detect? heat exchanger and pump water and on and off type control system is usually found on what type of boiler? package fire tube boiler the chemical used to perform water treatment test are called? reagents on turbine, what is between every set to rotating blades
stationary blades the color of R-404A refrigerant is? Orange what is used when a large load must be carried to maintain the proper exit position of turbine shaft? thrust bearing given a pressure drop calculates flow measurement across an orifice two widely used secondary element which connects differential pressure to a usable output signal? transmitter and receiver in what year was the first clen air act regulation passes? 1963 what should the water temperature be when leaving DA TANK? Within 3 to 5 degrees of entering temperature which type of stoker feed system use a ram feed? Underfeed?
how much water does it take to create one pound of steam? 1.0 lb. the color for H-407c refrigerant cyclinder? chocolate in a water tube boiler over heating of the tubes might be caused by? scale formation on the insdie of the water tube super critical boiler operate above the critical ________ of the water steam loop of the _________ and operating temperature above ___________degrees? pressure 3206.2 ; 705. the electrostatic precipitation collects fly ash in the flue gas by placing a? high voltage AC current to the collection plates, which causes the dust which of the following is technique to control particulates from boilers? fabric filter
a unit of force imposed on a unit of area is called? pressure which of the following statement concerning a superheater is true? the superheater safety valve is set at a lower pressure than the drum safety valve to be accurate when it is installed a mercury tube pressure control must be mounted. in a veritical position the ______ pump is a type of pump where high pressure steam enters the venture inlet and enter into the mixing tube with a lower pressure but higher temp injector which of the following is a technique is control nitrous oxide emissions? S.C.R Selective Catalytic a boiler is steaming at 50% of the load, and suddenly the fire goes out, in this case what happens to the water level? water shrinks and trips the LWCO
which of the following are the correct definition of "Critical Pressure" and critical temperature critical pressure is pressure at which water and steam have the same density ect.... which of the following type of pumps can be started with the discharge valve closed? centrifugal a chiller water coil is an example of _________ dehumidification? mechanical condensate pump remove water from the ________? condenser the erosion which occurs when steam or high velocity fluid flows through a throttled valve is called wire drawing air is bypassed around the air heater when? the boiler steam load is at a minimum
a high temperature hot water boiler is one where? the maximum operation temperature of the water is in excess of 250 degrees F operation pressure exceeding 160 which of the following oils must be used with R-134A and 410A? Polyester (POL) The perforated plate type baffle at the steam outlet in a boiler steam drum is installed to? aid in delivery of dry steam which winding coil a transformer in the coil that draws power from the power source? Primary it is necessary to keep a water seal on the atmosphere relief valve to? Stop air from getting into the condenser hardness can be reduced by heating water is called ______ hardness Temporary
Mechanical collectors remove fly ash from the stack emissions by using? A bag filter. What must you do to prevent air from leaking into the condenser? Pack the low pressure end of the turbine. Hardness that can be reduced only by chemical means of distillation is hardness.? Permanent Hardness If a vacuum gauge on a condenser reads 27.56 inches of mercury and the barometer reads 29.30 inches of mercury what is the absolute pressure in PSIA inside the condenser?
Given: In a boiler room there is a HRT boiler with the following dimension. The drums 96 inches in diameter and 36 feet long there are a total 90 tubes. What is the heating surface of the shell in square feet? 358.44 square feet Given: A boiler 7ft in diameter has 5/8-inch plate 1200 lbs. of tensile strength riveted joint, an efficiency of 85% and safety factor of .5 What is the maximum working PSI of the boiler? boiler?C.. Formula SxTxF
1200X1.6X.85=1632 FxR=.5X36= 1632/180=9.066X5=45. Given: A three phase 480 volt circuit draw of 84 amps. What is the electrical load by kilovolt amps? 70 Volts X AMPX1.73 480X84X1.73=69753.6/1000=69. What is the thermal efficiency percentage of a boiler with a stack temperature of 600 degrees F and a furnace temperature of 2800 degrees F?
2800 - 600=2200/2800=78.
