Heat Exchangers Review Flashcards
The heat flow from a tube to the attached fins would be by:
Conduction
Baffles in shell and tube type heat exchangers are used for:
Preventing dead bypass areas
Which baffles are normally used to change the shell side flow from parallel or counter flow into a mixed flow design?
Longitudinal baffles
To ensure that no mixing of shell and tube side fluids can occur as a result of tube sheet leaks, what is used?
Double tube sheets are used
The main function of a heat exchanger is to:
Reduce the temperature of one fluid, while increasing the temperature of the other
Compared to the fixed welded tube sheet type heat exchanger, “U” tube bundles used in heat exchangers help reduce problems related to:
Differential expansion and contraction
Cleaning the inside of the shell
Cleaning the outside of the tubes
Compared to the split backing ring design, the major disadvantage of the pull through floating head design is:
Larger clearances exist between the shell and the tube bundle
In a shell and tube heat exchanger, the most efficient heat exchange takes place with which design:
Counter flow
Floating tube sheets are principally designed to:
Float Axially
The shell side of a fixed tube sheet exchanger would be cleaned by:
Flushing
If the front head (channel head) of a heat exchanger was divided into two by the use of a channel head baffle, the tube side would have #___ passes.
2
Which baffle helps to reduce the eroding effect of the fluid in exchangers with high inlet velocities?
Impingement
When pulling a tube bundle from a multi-pass, shell and tube heat exchanger, what precautions should be observed?
Pull bundle using eye bolts
Support bundles on baffles when lifting
Ensure no toxic vapours are present
When lifting a large tube bundle with baffles, where would you support?
Support the bundle under the baffles or tube sheet
On a heat exchanger that has a floating head with a split-backing ring, what is bolted to the split-backing ring?
Floating head cover
The most common type of tube joint is the:
Expanded
All the fluids represented here are flowing in the same direction. The higher temperature Fluid 2 cannot be cooled:
(picture shows fluid 1 entering the top left, leaving bottom right, fluid 2 entering left leaving right side, parallel flow)
1
2===(=========)==2
1
Cannot be cooled below the highest temperature of Fluid 1
Stress on a fixed tube sheet exchanger is sometimes reduced by the use of:
An expansion joint in the shell
Photo shows;
Fluid entering top of shell/tube on left, longitudinal baffle horizontally, dividing into 2, fluid flows in, goes right, then down, then left and exit at bottom;
How many passes?
One pass
The device used to prevent internal components from corroding due to electrical currents being produced by dissimilar metals is a (an):
Sacrificial zinc anode
Which method is used first on a double tube sheet exchanger to determine which tube sheets are leaking?
Visual inspection of the tube sheet
Routing the fluid through the inside of the tubes would be necessary if the fluid was:
High pressure
A standardized exchanger size designation of 500 mm - 4000 mm would mean:
Shell diameter is 500 mm and tube length is 4000 mm
A heat exchanger operates at 275 psi. What would be the recommended hydro test pressure?
412.5 psi
1.5x operating pressure
As a safety precaution when removing the channel head for tube inspection, which set of studs should be loosened and removed first?
Bottom
let any liquids flow out first if any.
