Bell & Gossett HT 50B SM B&G Series U Heat Exchangers Removable Bundle Design User Manual

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2. Start operation gradually. Do not admit hot fluid to the unit

suddenly when empty or cold. Do not shock unit with cold

fluid when unit is hot.

CAUTION: Fluids must be gradually introduced to

the unit. Failure to do so can cause damage to the

heat exchanger.

3. Do not operate equipment under conditions in excess of

those specified on nameplate.

WARNING: Failure to operate the heat exchanger

within the design pressure and temperature on the

nameplate may result in damage to the heat exchanger

and potential injury to adjacent personnel.

CAUTION: Fluid and/or steam velocities in excess

of design operating conditions on either the shell or

tube side of the heat exchanger can cause damaging

tube erosion and/or vibrations. Result is internal leakage

and mixing of the hot and cold media. Proper setting of

system controls is required.

4. In all installations, there should be no pulsation of fluids

since this causes vibration and strain with resulting leaks.

5. Retighten bolting on all gasketed joints after the heat

exchanger has reached operation temperatures to prevent

leaks and gasket failures. Retightening should be done

uniformally and in a diametrically staggered pattern as

illustrated in “MAINTENANCE”.

6. On high pressure and high temperature applications where

an “HTWU/DHTWU” heat exchanger is used or any appli-

cation where spiral wound gaskets are required, it is rec-

ommended that the gasketed joints of the heat exchanger

be retightened to the required torque (see “MAINTE-

NANCE”) after 24 hours at operating pressures and tem-

peratures to compensate for any relaxation or creep that

may have occurred.

7. In shutting down, flow of hot medium should be shut off

first. If it is necessary to stop circulation of cooling medium

the circulation of hot medium should also be stopped by

by-passing or otherwise.

8. Drain all fluids when shutting down to eliminate the possi-

bility of freezing and corrosion. To guard against water

hammer, condensate should be drained from steam

heaters and similar apparatus both when starting up and

when shutting down.

9. Heat exchangers that are out of service for extended

periods of time should be protected against corrosion as

described in the storage requirements for new heat

exchangers.
Heat exchangers that are out of service for short periods

and use water as the flowing medium should be thoroughly

drained and blown dry with warm air, if possible. If this is

not practical, the water should be circulated through the

heat exchanger on a daily basis to prevent stagnant water

conditions that can ultimately cause corrosion.

8. Set exchangers level and square so that pipe connections

may be made without forcing.

CAUTION: It is up to the installer to provide

adequate support for tank heater units (2) two feet or

longer when installing them in a tank. Failure to provide

adequate support may result in premature tube failure

and/or failure of the tube/tubesheet mechanical roll joint.

9. Inspect all openings in exchanger for foreign material.

Remove all wooden plugs and shipping pads just before

installing. Do not expose units to the elements with pads

or other covers removed from nozzles or other openings

since rain water may enter the unit and cause severe dam-

age due to freezing.

10. Be sure the entire system is clean before starting operation

to prevent plugging of tubes with sand or refuse. The use

of strainers in settling tanks in pipe lines leading to the unit

is recommended.

11. Drain connections should not be piped to a common

closed manifold.

12. Steam hammer can cause serious damage to the tubes

of any heat exchanger. A careful consideration of the fol-

lowing points before an installation is made can prevent

costly repairs which may be caused by steam hammer.
a. A vacuum breaker and/or vent, should be used in

accordance with the type of steam system installed.

b. The proper trap for the steam system installed should

be used.

c. The trap and condensate return line to the trap should

be properly sized for the total capacity of the convertor.

d. The trap should be sized for the pressure at the trap,

not the inlet pressure to the steam controller.

e. Condensate should be piped and pitched to a conden-

sate receiver, condensate return pump or drain at an

elevation below the heat exchanger.

CAUTION: During times of shutdown, volumetric

expansion can occur. We recommend the installa-

tion of a properly sized relief valve on both sides of the

the heat exchanger. Failure to do so can cause damage

to the heat exchanger.

OPERATION

1. When placing a unit in operation, open the vent connec-

tions and start to circulate the cold medium only. Be sure

that the passages in the exchanger are entirely filled with

cold fluids before closing the vents. The hot medium

should then be introduced gradually until all passages are

filled with liquid, close vents and slowly bring the unit up to

temperature.