Stationary Engineer Exam Questions And Answers 100% Solved

Stationary Engineer Exam Questions And Answers 100% Solved What is a water tube boiler? What are five of the advantages & disadvantages of a water tube boiler? Name four types of water tube boilers. - answerIn a water tube boiler the products of combustion pass around the tubes containing boiler water. Advantages: 1) Rapid steamers. 2) Use less water. 3) Less chance of explosion. 4) No flat surfaces. 5) Smaller tube size. Disadvantages: 1) They have elaborate settings. 2) Field assembled. 3) Initial cost per pound of steam is higher. 4) Greater number of openings, thus more air infiltration. 5) Larger floor space. Types: 1) B. & W. 2) Sterling. 3) Heine. 4) Riley Consolidated. 5) F.M. Package. 6) M.H. series. 7) Cross drum - straight tube. 8) Type A. 9) Type D. What is a fire tube boiler? What are five of the advantages & disadvantages of a fire tube boiler? Name four types of fire tube boilers. - answerIn a fire tube boiler the products of combustion pass through the tubes or flues, which are surrounded by water. Advantages: 1) Low initial cost. 2) Compact. 3) Factory assembled. 4) Very little setting required. 5) Fast installation. Disadvantages: 1) Liable to disastrous explosions because drums & joints are set over the fire. 2) Inaccessible for inspection. 3) Slow steamers. 4) Poor circulation. 5) Inefficient. 6) Pressure & capacity are limited. Types: 1) H.R.T. 2) Locomotive. 3) Scotch Marine. 4) Vertical fire tube. What type stays are used in wet back (Scotch Marine) type boilers? - answerStay bolts & through stays. These sometimes will have telltales drilled in them. Describe a sectional boiler - answerAs the name implies, the sectional headers are built up of vertical sections or units. A sufficient number of sections are clamped together to form the desired size boiler. These boilers can be erected in an existing building by carrying them in piece by piece. What is a superheater? What are the advantages of a superheater? - answerA superheater is a device used to raise the temperature of the steam without raising the pressure. Advantages: (a) Increases efficiency of the boiler. (b) Deliveries drier steam. (c) Dryer steam can be transmitted long distances with minimal heat loss. (d) With dryer steam, condensation & erosion are reduced. What is a convection type superheater? What is a radiant type superheater? What is the third type of superheater? - answerConvection superheater is placed in the gas passage of the furnace, usually between the first & second pass. Little to no radiation will reach this type. Radiant superheater is placed in position to absorb radiant heat from the furnace by direct radiation. It is set over the fire. The third type is a combination radiant & convection What is an economizer? What is a pre-heater? - answerAn economizer (feedwater economizer) is a heat exchanger located in the breaching between the boiler & stack. It is designed to recover waste heat from the products of combustion by pre-heating the feedwater. The air pre-heater consists of a series of tubes or plates that have hot gases on one side & incoming air on the other. The heat in the hot gases leaving the boiler is recovered by the incoming air, thereby reducing stack temperatures & increasing the boiler efficiency. What is a waterwall? - answerA waterwall is a set of tubes containing boiler water set in the refractory. They absorb heat that would otherwise be lost to the refractory & increase the capacity of the boiler. What is the A.S.M.E. code? What code information is stamped on the boiler? What is an A.S.M.E. stamp? Where are the code markings found on a boiler? - answerAmerican Society of Mechanical Engineers. It is a code of minimum standards for the safe construction of pressure vessels. Stamped on the boiler shell or a plate attached to the shell there will be the safe working pressure, date of manufacture, name of manufacturer, type of material used, horsepower rating, square feet of heating surface, steam generation in pounds per hour, & fuel designed for. The A.S.M.E. symbol stamp will identify the boiler or accessory type. On a fire tube boiler, it will be located on the right side near the front, by the water column. On a water tube boiler, it will be located next to the manhole on the steam drum. What is the cross section of a 1" bolt? - answer.7854 (1/4 {3.14}) x diameter x diameter. .7854 (1/4 {3.14}) x 1 x 1 = .7854 square inch. What is an alloy? Name five. - answerA mixture of two or more metals. Brass, bronze, steel, stainless steel, cast iron, babbitt, & bell metal. At what pressure is the use of cast iron fittings permitted? - answer5 psi or 250° F. Not to exceed either. What is meant by the factor of safety? - answerThe comparison of the tensile strength to the actual working stress. The bursting pressure divided by the working pressure. What is the factor of safety for boilers, flywheels, & pipe? - answerNew boilers are 4. Pre- owned boilers constructed to A.S.M.E. code is 5. Flywheels are 3. Pipe is 8. What is a lap joint? What is a butt joint? What is a butt strap joint? - answerA lap joint is when one plate overlaps the other & is joined. A butt joint is when two ends of the plate meet end to end & are joined. A butt strap joint is when two ends of the plate meet end to end & are joined by a plate. One plate is a single butt strap joint, two plates are a double butt strap joint. Is the longitudinal joint the strongest part of the boiler? - answerNO! it is the strongest type joint, but any joint is the weakest part of a boiler Two boilers are made of the same grade of steel, same thickness of plate, & same type of joints. One is 30" diameter & the other is 60" diameter. Which will withstand the greatest working pressure? - answerThe 30" boiler has less total pressure. .7854 x 30 x 30 x 120psi = 84,823 lbs total pressure on a 30" head. .7854 x 60 x 60 x 120psi = 339,292 lbs total pressure on a 60" head. What are tube ligaments? - answerthe area between the tube holes on the tube sheet What type of stays are used in the heads of water tube boilers? - answerThere are no stays. The head of the boiler drum is shaped with a die, which dishes & forms them into the shape they would take as a result of the pressure to which they will be subjected Why is a row of tubes sometimes left out of a H.R.T. boiler? - answerTo improve circulation which reduces carryover. How are tubes secured in a tube sheet? Why are some tube ends in a water tube boiler beaded? - answerIn a fire tube boiler they are rolled & beaded. In a water tube boiler they are rolled and flared. For drainage of the top drums & to prevent air pockets in the lower drums. Is it necessary to brace or stay a flat surface? Name three types of stays. - answerYes, to overcome the force on heads & flat surfaces. Where there are no tubes, braces & stays must be provided to prevent bulging of the boilerplate. Through bolt, stay bolt, diagonal stay, gusset stay, jaw stay, "T" stay, "J" stay, "Y" stay, crowfoot stay, palm stay, head brace, screw, & vertical bar stay. Describe a through stay. Why are hollow bolts used on water legs? - answerA through stay runs from one tube sheet to the other or from one surface to the other. The rod is threaded on both ends. A nut is placed on the inside & on the outside of the plates. A small hole is drilled into the stay bolt so if it was to fail, a leak will develop & will be detected at once. Describe a diagonal & gusset stay. Where would each be used? - answerA diagonal stay is made of flat material similar to the boiler shell & is attached directly to the boiler shell & head or tube sheet. A gusset stay consists of boilerplate riveted to the shell & head or tube sheet by means of angle iron. They are more rigid. Both are used to brace right angle surfaces. Why are handholes & manholes made oval instead round? What are the minimum sizes for manhole & handhole openings? - answerSo they can be inserted into & removed from their respective openings in the b