Heat exchangers
For removal of sludge from in the inside of the shell of a fuel oil heater or lube oil cooler, what is typically the preferred method of cleaning? Circulating hot distillate oil. Blowing out with compressed air or a steam lance. Chemical cleaning with descaling compounds. Mechanical cleaning with specially designed brushes.
A
A steam supplied heat exchanger will fail to maintain the designed quantity of heated liquid output if the __________. steam side shell absolute pressure is decreased heat exchanger drain is leaking I only II only Both I and II Neither I nor II
A
For marine-type shell-and-tube heat exchangers, what is the most common arrangement for baffles? Segmental Disc Doughnut Solid
A
How may a suspected tube leak on a shell-and-tube jacket water cooler most easily be located? Isolate, drain, and dry the salt water side of the heat exchanger. Remove the water box inspection plates. Visually inspect the tube sheets for signs of seepage at each of the tube ends. Isolate, drain, and dry the salt water side of the heat exchanger. Pressurize the seawater side with compressed air. Visually inspect the jacket water expansion tank for bubbles. Isolate, drain, and dry both the salt water and jacket water sides of the heat exchanger. Remove the water box inspection plates. Visually inspect the tube sheets for signs of seepage at each of the tube ends. Isolate, drain, and dry the jacket water side of the heat exchanger. Remove the shell inspection plates. Visually inspect the tubes along the tube lengths for seepage.
A
If a fluorescent dye penetrant and ultra-violet light are used for leak detection on a heat exchanger, what would be the indication of a confirmed leak? A bright green glow at the site of leakage. A bright orange glow at the site of leakage. A bright purple glow at the site of leakage. A bright red glow at the site of leakage.
A
If a heat exchanger is designed to heat heavy fuel oil using steam as a heating medium, what statement is true? The heavy fuel oil gains sensible heat, and the steam loses latent heat. The heavy fuel oil loses sensible heat, and the steam gains latent heat. The heavy fuel oil gains latent heat, and the steam loses sensible heat. The heavy fuel oil gains sensible heat, and the steam loses sensible heat.
A
In a heat exchanger, excessive fluid velocity should be avoided to prevent __________. erosive tube failure waterside deposit buildup tube sheet bowing water hammer damage
A
The floating end of a shell-and-tube type cooler utilizes a packing ring to ______. prevent leakage past the floating end tube sheet modify to a mixer type cooler dissipate heat baffle cooling water so it can be directed on a multiple pass
A
What would be the most likely indication that a shell-and-tube lube oil cooler had in internal leak permitting mixing of the two fluids? Dropping level and frequent need to add make-up oil to engine sump. Corrosion of engine internal parts in contact with lube oil. Rising level in engine lube oil sump. Drop in viscosity of engine lube oil.
A
When a heat exchanger is used as a cooler, excessive cooling water flow should be avoided to prevent __________. erosive tube failure waterside deposit buildup tube sheet bowing water hammer damage
A
When placing a shell-and-tube heat exchanger such as a jacket water cooler into service, to insure optimal heat transfer what statement represents the correct operating procedure? Both the water box and shell vent valves should be opened to expel any entrapped air and then reclosed. Both the water box and shell drain valves should be opened to expel any entrapped air and then reclosed. Both the water box and shell vent valves should be opened to expel any entrapped sediment and then reclosed. Both the water box and shell drain valves should be opened to expel any entrapped sediment and then reclosed.
A
Which saltwater-cooled heat exchanger arrangement and location would be the LEAST likely to become air-bound on the seawater side? Vertically arranged cooler located below the water line. Horizontally arranged cooler located above the water line. Vertically arranged cooler located above the water line. Horizontally arranged cooler located below the water line.
A
With regard to the relative flow patterns through the tubes and the shell of shell-and-tube heat exchangers, what statement is true? In a counter-flow heat exchanger, the flow through the tubes and the flow through the shell are in opposite directions. In a counter-flow heat exchanger, the flow through the tubes and the flow through the shell are in the same direction. In a parallel-flow heat exchanger, the flow through the tubes and the flow through the shell are in opposite directions. In a cross-flow heat exchanger, the flow through the tubes and the flow through the shell are in opposite directions.
A
A steam supplied heat exchanger will fail to maintain the designed quantity of heated liquid output if the __________. steam supply absolute pressure is increased tubes are leaking I only II only Both I and II Neither I nor II
B
Assuming oil and water flow rates remain the same, what would be the effect of scale formation occurring on the inside of the cooling water tubes of a lube oil heat exchanger? Water temperature outlet temperature will decrease and the lube oil temperature will decrease. Water temperature outlet temperature will decrease and the lube oil temperature will increase. Water temperature outlet temperature will increase and the lube oil temperature will decrease. Water temperature outlet temperature will increase and the lube oil temperature will increase.
B
For a shell-and-tube heat exchanger, which tube pitch pattern would feature "see-through" lanes and would most easily allow external mechanical cleaning of the tubes? Rotated triangular tube pitch Square tube pitch Triangular tube pitch Rotated square tube pitch
B
For soft scale deposits on the inside of the tubes of a seawater-cooled shell-and-tube heat exchanger, what is typically the preferred method of cleaning? Blowing out with compressed air or a steam lance. Mechanical cleaning with specially designed brushes and/or flushing with hot freshwater. Chemical cleaning with descaling compounds Mechanical cleaning with specially designed reamers or cutting tools.
B
If a heat exchanger is designed to cool lubricating oil using sea water as a cooling medium, what statement is true? A. The lubricating oil loses sensible heat, and the sea water loses sensible heat. B. The lubricating oil loses sensible heat, and the sea water gains sensible heat. C. The lubricating oil loses latent heat, and the sea water gains latent heat. D. The lubricating oil gains sensible heat, and the sea water loses sensible heat.
B
If a seawater-cooled shell-and- tube lubricating oil cooler has the seawater inlet and outlet connections on the opposite end water boxes, in terms of the number of passes, what statement is true? The number of fluid passes cannot be determined. The tube-side fluid flow pattern is single-pass. The tube-side fluid flow pattern is four-pass. The tube-side fluid flow pattern is two-pass.
B
The transfer of heat within a solid, caused by the application of thermal energy, is called ___________. radiation conduction convection condo-radiation
B
What is the most common arrangement for a compact heat exchanger such as that used on an air conditioning cooling coil located in a ventilation supply duct? Plate-fin set up as a serpentine plate. Finned-tube set up as a serpentine coil. Finned-tube set up as a spiral coil. Finned-tube set up as a helical coil.
B
What type of lube oil cooler is shown in the illustration?See illustration GS-0122. Self venting Shell-and-tube Bundle and stack Plate type
B
Which of the following provisions for thermal expansion for shell-and-tube heat exchangers only requires a single tube sheet located at one end? A shell-and-tube heat exchanger featuring a floating tube sheet. A shell-and-tube heat exchanger featuring U-tube type tubes. A shell-and-tube heat exchanger featuring a packed tube sheet. A shell-and-tube heat exchanger featuring bayonet type tubes.
B
Which saltwater -cooled heat exchanger arrangement and location would be MOST problematic in terms of keeping the seawater side filled? Vertically arranged cooler located below the water line. Horizontally arranged cooler located above the water line. Horizontally arranged cooler located below the water line. Vertically arranged cooler located above the water line.
B
Zinc anodes are installed in a marine sea water heat exchanger cooling system to ________. inhibit oxidation control electrolysis prevent scaling eliminate corrosion
B
Besides a visual inspection upon disassembly, what method can be used to check for suspected leakage through a heat transfer plate of a plate type heat exchanger? One side of the plate is cleaned and coated with a water-seeking paste, and the other side is sprayed with water. One side of the plate is cleaned and sprayed with a fluorescent dye penetrant, and the other side is viewed with an infra-red heat source. One side of the plate is cleaned and sprayed with a fluorescent dye penetrant, and the other side is viewed with an ultra-violet light. One side of the plate is cleaned and sprayed with a fluorescent dye penetrant, and the other side is viewed with an ordinary flashlight.
C
Which of the following provisions for thermal expansion for shell-and-tube heat exchangers has a tube arrangement featuring a "tube-within-a-tube"? A shell-and tube heat exchanger featuring a packed tube sheet. A shell-and-tube heat exchanger featuring a floating tube sheet. A shell-and-tube heat exchanger featuring bayonet type tubes. A shell-and-tube heat exchanger featuring U-tube type tubes.
C
Concerning the baffles of a shell-and-tube heat exchanger, what statement is true? The baffles are used to support the tubes, guide flow, and decrease the velocity of the fluid flowing through the shell. The baffles are used to support the tubes, guide flow, and increase the velocity of the fluid flowing through the tubes. The baffles are used to support the tubes, guide flow, and increase the velocity of the fluid flowing through the shell. The baffles are used to support the tubes, guide flow, and decrease the velocity of the fluid flowing through the tubes.
C
Erosive tube failure in a heat exchanger can result from __________. high temperature waterside fouling excessive cooling water velocity poor heat transfer
C
For a given shell diameter and tube sizes for a shell-and-tube heat exchanger, which tube pitch pattern would be the most compact design allowing for the most tubes? Rotated triangular tube pitch Rotated square tube pitch Triangular tube pitch Square tube pitch
C
If a heat exchanger is designed to condense refrigerant vapor using central cooling fresh water as a condensing medium, what statement is true? The refrigerant vapor loses latent heat, the central cooling fresh water loses latent heat. The refrigerant vapor loses sensible heat, the central cooling fresh water gains latent heat. The refrigerant vapor loses latent heat, the central cooling fresh water gains sensible heat. The refrigerant vapor gains latent heat, the central cooling fresh water loses sensible heat.
C
If a seawater-cooled shell-and-tube lubricating oil cooler has the seawater inlet and outlet connections on the opposite end water boxes, in terms of the number of passes, what statement is true? The number of fluid passes cannot be determined. The tube-side fluid flow pattern is four-pass. The tube-side fluid flow pattern is single-pass. The tube-side fluid flow pattern is two-pass.
C
In a shell- and-tube heat exchanger, which of the following tube types would be LEAST susceptible to tube-side fouling? Coated-surface tubes Corrugated tubes Plain tubes Finned tubes
C
The general purpose of a heat exchanger is to ______. maintain steady pressure in a system eliminate hot air from the condenser heat, or cool one fluid by means of another fluid reduce the engine room temperature in tropical climates
C
The general purpose of a heat exchanger is to __________. eliminate hot air from the condenser maintain steady pressure in a system heat, or cool one fluid by means of another fluid reduce the engine room temperature in tropical climates
C
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed? Cross Counter Parallel Circular
C
Tube scaling in heat exchangers causes the heat transfer rate to decrease because the ________. surface area of the tube decreases cooling fluid outlet temperature decreases thermal conductivity of the scale is very low flow through the heat exchanger becomes more turbulent
C
When placing a shell-and-tube heat exchanger with a non-removable tube bundle such as a lube oil cooler with fixed tube sheets into service, to avoid thermal shock what statement represents the correct operating procedure? Introduce the cooling water first, then gradually introduce the lube oil until full flow is established to avoid thermal shock. Introduce the lubricating oil first, then gradually introduce the cooling water until full flow is established to avoid thermal shock. Introduce both the cooling water and the lubricating oil simultaneously and gradually to avoid thermal shock. Introduce both the cooling water and the lubricating oil simultaneously establishing full flow of both fluids immediately to avoid thermal shock.
C
When taking a shell-and-tube heat exchanger with a removable tube bundle such as a bayonet-tube heavy fuel oil service heater out of service, to prevent water hammer what statement represents the correct operating procedure? Open wide the condensate drains first. Gradually close down and secure the steam, then close the condensate drains when no longer issuing dry steam. Finally, secure the heavy fuel oil. Secure the heavy fuel oil first, then crack open the condensate drains. Gradually close down and secure the steam, then close the condensate drains when no longer issuing dry steam. Crack open the condensate drains first. Gradually close down and secure the steam, then close the condensate drains when no longer draining condensate. Finally, secure the heavy fuel oil. Secure the heavy fuel oil first, then crack open the condensate drains. Gradually close down and secure the steam, then close the condensate drains when no longer draining condensate.
C
Which of the following statements is true concerning lube oil coolers? The temperature of the oil is less than that of the cooling water. The pressure of the oil is less than that of the cooling water. The pressure of the oil is greater than that of the cooling water. Magnets are installed in the tube sheets to remove metal particles.
C
With regard to the flow patterns associated with plate type heat exchangers, which flow pattern is able to achieve counter-flow on opposite sides of each heat exchange plate? The flow pattern where one fluid makes a single pass and the other makes multiple passes through the heat exchanger. The flow pattern where each fluid makes multiple passes through the heat exchanger. The flow pattern where each fluid makes a single pass through the heat exchanger. It is not possible for each heat exchanger plate to achieve counter flow on opposite sides.
C
If both the shell-and-tube lube oil cooler and shell-and-tube jacket water cooler of a diesel engine are seawater cooled, what statement is true? Seawater flows through the shells of both the lube-oil and jacket-water coolers. Seawater flows through the tubes of the lube-oil cooler and through the shell of the jacket- water cooler. Seawater flows through the tubes of the jacket-water cooler and through the shell of the lube- oil cooler. Seawater flows through the tubes of both the lube-oil and jacket-water coolers.
D
For stubborn, hard scale deposits on the inside of the tubes of a seawater-cooled shell-and-tube heat exchanger, what is typically the preferred method of cleaning? Mechanical cleaning with specially designed brushes. Flushing with hot fresh-water. Mechanical cleaning with specially designed reamers. Chemically cleaning with descaling compounds.
D
Heat exchanger tubes can be protected against erosion and abrasion by the use of __________. metallic packing on the inlet end fiber bushings in the ferrules zinc pencils on the waterside plastic tube end protectors
D
If a heat exchanger is designed to evaporate sea water using diesel engine jacket water as an evaporating medium, what statement is true? The sea water gains latent heat, and the diesel engine jacket water loses latent heat. The sea water loses latent heat, and the diesel engine jacket water gains sensible heat. The sea water gains sensible heat, and the diesel engine jacket water loses latent heat. The sea water gains latent heat, and the diesel engine jacket water loses sensible heat.
D
In a shell-and-tube type heat exchanger, the most common cause of decreased performance is __________. loose tube bundle baffle plates failure of the baffle plate rupture of the tube bundle fouling on the seawater side
D
In a shell-and-tube type hydraulic fluid cooler, the amount of heat transferred from the hydraulic fluid to the cooling water depends upon __________. the temperature of the hydraulic fluid the flow rate of both the cooling water and the hydraulic fluid the temperature of the cooling water all of the above
D
In heat exchangers, seawater pressure should be maintained lower than freshwater pressure to __________. eliminate scaling problems on the saltwater side reduce erosion of heat exchanger surfaces ease the load on the saltwater service pump prevent contamination should leaks develop
D
Sacrificial zinc anodes are used on the saltwater side of heat exchangers to __________. keep heat transfer surfaces shiny and clean prevent rapid accumulation of marine growth provide a protective coating on heat exchanger surfaces reduce electrolytic action on heat exchanger metals
D
Suppose a diesel engine is fitted with seawater-cooled lube oil and jacket water coolers. What statement is true concerning the system operating pressures? The jacket water pressure is maintained lower than the sea water pressure in the jacket water cooler, and the lube oil pressure is maintained higher than the sea water pressure in the lube oil cooler. The jacket water pressure is maintained lower than the sea water pressure in the jacket water cooler, and the lube oil pressure is maintained lower than the sea water pressure in the lube oil cooler. The jacket water pressure is maintained higher than the sea water pressure in the jacket water cooler, and the lube oil pressure is maintained lower than the sea water pressure in the lube oil cooler. The jacket water pressure is maintained higher than the sea water pressure in the jacket water cooler, and the lube oil pressure is maintained higher than the sea water pressure in the lube oil cooler.
D
The interior of some diesel engine saltwater heat exchangers are protected from electrolytic corrosion by the use of __________. aluminum plates lead cathodes copper baffle plates zinc plates
D
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will __________. remain constant along the tube's length be greatest in a single pass counter flow heat exchanger remain constant throughout the heat exchanger vary from section to section throughout the heat exchanger
D
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will __________. remain constant along the tube's length vary according to the fluid pressures remain constant throughout the heat exchanger vary from section to section throughout the heat exchanger
D
What is the primary indication of fouling of a heat exchanger? A decreased pressure drop associated with the side where the fouling exists and a decreased temperature differential between the two fluids exchanging heat. A decreased pressure drop associated with the side where the fouling exists and an increased temperature differential between the two fluids exchanging heat. An increased pressure drop associated with the side where the fouling exists and a decreased temperature differential between the two fluids exchanging heat. An increased pressure drop associated with the side where the fouling exists and an increased temperature differential between the two fluids exchanging heat.
D
What prevents the two fluids in a plate type heat exchanger from coming into direct contact with each other and mixing? The chevrons and corrugations between the individual heat transfer plates. The metal-to-metal seal between the individual heat transfer plates. The metal-to-metal seal between the covers (pressure plates). The pipe to groove seals between the individual heat transfer plates.
D
What statement is true concerning the heat transfer rates through a heat exchanger boundary wall by conduction? Heat transfer rates are inversely proportional to the temperature gradient across the wall, and directly proportional to the area of the wall and the wall thickness. Heat transfer rates are inversely proportional to the temperature gradient across the wall and the area of the wall, and directly proportional to the wall thickness. Heat transfer rates are directly proportional to the temperature gradient across the wall, and inversely proportional to the area of the wall and the wall thickness. Heat transfer rates are directly proportional to the temperature gradient across the wall and the area of the wall, and inversely proportional to the wall thickness.
D
What type of flow pattern would be associated with a forced-convection finned-coil heat exchanger such as an air-cooled hydraulic oil cooler? Counter flow Series flow Parallel flow Cross flow
D
What would be the most likely indication that a plate type jacket water cooler had an internal leak permitting mixing of the two fluids? Rising level and overflowing of the jacket water expansion tank. Drop in concentration of corrosion inhibitor package of jacket water. Excessive scale build-up on the various cylinder jacket surfaces. Dropping level and frequent need to top off jacket water expansion tank.
D
When placing a shell-and-tube heat exchanger with a removable tube bundle such as a bayonet- tube heavy fuel oil service heater into service, to avoid thermal shock what statement represents the correct operating procedure? Introduce the heavy fuel oil and steam simultaneously establishing full flow of both fluids immediately to avoid thermal shock. Introduce both the heavy fuel oil and steam simultaneously and gradually to avoid thermal shock. Introduce the steam first, then gradually introduce the heavy fuel oil until full flow is established to avoid thermal shock. Introduce the heavy fuel oil first, then gradually introduce the steam until full flow is established to avoid thermal shock.
D
When placing a shell-and-tube heat exchanger with a removable tube bundle such as a bayonet- tube heavy fuel oil service heater into service, to prevent water hammer what statement represents the correct operating procedure? Crack open the condensate drains first. Gradually introduce the steam, then close the condensate drains when no longer draining condensate and issuing dry steam. Finally, introduce the heavy fuel oil. Introduce the heavy fuel oil first, then crack open the condensate drains. Gradually introduce the steam, then close the condensate drains when no longer issuing dry steam and draining condensate. Crack open the condensate drains first. Gradually introduce the steam, then close the condensate drains when no longer issuing dry steam and draining condensate. Finally, introduce the heavy fuel oil. Introduce the heavy fuel oil first, then crack open the condensate drains. Gradually introduce the steam, then close the condensate drains when no longer draining condensate and issuing dry steam.
D
When securing a seawater- cooled shell-and-tube heat exchanger for an extended period of time, what statement represents the recommended operating procedure? The seawater side of the heat exchanger should be drained, then flushed with freshwater and left completely filled with freshwater. The seawater side of the heat exchanger should be drained by opening the drain valves, while insuring that the vent valves remain closed while draining. The seawater side of the heat exchanger should be left completely filled with seawater. The seawater side of the heat exchanger should be drained by opening the drain valves, while insuring that the vent valves remain open while draining.
D
When taking a shell-and-tube heat exchanger with a removable tube bundle such as a bayonet-tube type heavy fuel oil service heater out of service, to avoid thermal shock what statement represents the correct operating procedure? Secure both the steam and heavy fuel oil simultaneously and immediately to avoid thermal shock. Secure the heavy fuel oil first, then gradually secure the steam to avoid thermal shock. Secure the steam and heavy fuel oil simultaneously and gradually to avoid thermal shock. Gradually secure the steam first, then secure the heavy fuel oil to avoid thermal shock.
D
Which non-ferrous alloy is most commonly used for heat exchanger tubes and possesses a high resistance to corrosion? Red brass Nautical bronze Aircraft aluminum Copper nickel
D
Which of the following statements is true concerning a radiator type heat exchanger? Raw water is the cooling medium. Water cooled exhaust elbows remove the heat. The surge tank must be located a minimum of 4 feet above the highest finned tube. Air flow provided by a fan is used as the cooling medium.
D
Which of the listed figures represents the configuration and alignment of the inlet/outlet head, as viewed from the tube side?See illustration GS-0122. A B C D
D
With regard to the number of passes through the tubes of shell-and-tube heat exchangers, what statement is true? In two-pass and four-pass heat exchangers, the inlet and outlet tube-side fluid connections are at opposite ends. In single-pass and two-pass heat exchangers, the inlet and outlet tube-side fluid connections are at opposite ends. In single-pass and two-pass heat exchangers, the inlet and outlet tube-side fluid connections are at the same end. In two-pass and four-pass heat exchangers, the inlet and outlet tube-side fluid connections are at the same end.
D