GENERAL

The Chromalox Horizontal Electric Vaporizer is a thoroughly engineered pre-tested package, designed to give years of service, virtually maintenance free if properly installed. The CHTV series is ASME certified for 150 PSI at 750°F and is available in four models, each with basic features that comply with the National Electrical Code. Model CHTV has general-purpose NEMA I con- struction and can be used where no hazards exist. Model CHTVO is oil and dust tight as specified by NEMA XII standards. Model CHTVW can be used where weather-resistant construction is required and is constructed according to NEMA IV specifications.

Model CHTVX, Class 1, Group D, Division 1 is explosion-resis- tant and is constructed to operate in hazardous or explosive areas. WARNING: Vessel and pipe surfaces could achieve temperatures higher than allowed for Class 1, Group D, Division 1 hazardous areas. Common to all four models: OCE (open coil element) type heating elements installed in 3”, schedule 40 seamless carbon steel pipes; watt density on the outside of the pipe surface is 10 watts per square inch; elements are removable without draining the fluid in the vaporizer; requirements 208, 240, 480 and 550 volt, 3 phase, 60 cycle, 15 to 300kW.

INSTALLATION

CAUTION: This vaporizer is not for use with water or ethylene glycol and water mixtures as the heat transfer media. Check with your local Chromalox Sales and Application Engineer to be sure that you are using an accepted heat transfer media in this vapor- izer or consult PQ301.

Note: When installing the vaporizer, allow a minimum of 3 feet for removing heating element if, and when, necessary.

HYDRAULIC OR MECHANICAL:

Note: The CHTVW vaporizer should be mounted so that the con- trol box does not fall in direct sunlight.

The bed plate should be mounted on solid foundation, prefer- ably level.

The pipe lines from the Chromalox vaporizer to the process should be the same size as the vaporizer’s piping connections. All piping should be arranged so that the vaporizer is not subject to extreme nozzle loading due to thermal expansion and contraction of pipe lines. If these instructions are not followed, cracks could devel- op in the vaporizer where the inlet and outlet nozzles are attached.

1.The piping of the entire system should be arranged to minimize pockets where air may be trapped. Manual air vents or bleeder valves should be provided at all high points in the system and every time the flow of the condensate has to drop.

2.Condensate return systems:

A.Gravity return type: The simplest and most easily operat- ed type of vaporizer is one in which the condensate from the heating equipment is returned to the vaporizer by gravity, thus providing a system without moving parts. Such a sys- tem is possible if there is sufficient difference in elevation between the process and the vaporizer so the static liquid head will counter-balance all frictional losses in the vapor- izer, vapor piping process and condensate return piping without flooding the heated equipment. See Figure 1 for a typical schematic piping diagram.

B.Pumped return type: Where there is insufficient differ- ence in elevation between the vaporizer and the process, the condensate must be returned to the vaporizer by a pump.

Normally, these pumps are of the centrifugal type; howev- er, positive displacement pump may also be used. See Figure 2 for a typical schematic piping diagram.

3.Hartford Loop – In gravity return systems a Hartford Loop should be incorporated where the condensate is returned to any point below the desired liquid level of the vaporizer.

A Hartford Loop consists of a line without valves outside of the vaporizer connecting the vapor outlet and the condensate inlet. The condensate return line is connected to the vapor-con- densate line or loop at the same elevation as the lowest permis- sible level in the vaporizer. Thus, a vacuum in the heated equip- ment can then pull liquid from the vaporizer (or a closed valve in the vapor line can force liquid from the vaporizer) only until the level in the vaporizer falls to the level of this connection. Also, the resultant liquid hammering will give warning that the liquid level in the vaporizer is too low. (See Figure 1 below.)

4.Note: All flange connections should be checked and tightened if necessary. These sometimes loosen during transit.

ELECTRIC:

 

 

Control Box Size

No.

 

Control

kW

Volts

H L D

Circuits

Accomplished By

15

240

 

 

1

Pressure

Thru

or

30 x 24 x 8

1

Control with

30

480

 

 

1

Switch

40

240

 

 

1

Pressure

Thru

or

30 x 30 x 8

2

Control with

60

480

 

 

2

Switches

75

240

 

 

1

Pressure

Thru

or

42 x 30 x 8

3

Control with

100

480

 

 

3

Switches

 

 

 

 

1

Proportional

125

 

 

 

Pressure Control

Thru

480

48 x 36 x 8

4

with 4-step

150

 

 

 

electronic stepper

 

 

 

 

1

Proportional

175

 

 

 

Pressure Control

Thru

480

60 x 36 x 8

6

with 6-step

300

 

 

 

electronic stepper

Jacketed

 

 

 

 

Vapor Outlet

Vessel

 

 

 

 

 

 

 

 

Safety

Jacketed

 

 

 

 

Valve

 

 

 

Vapor

Vessel

 

 

 

 

 

 

 

 

 

 

 

 

Outlet

 

 

 

 

Hartford

 

 

 

 

Liquid

Loop

 

 

 

Heater Terminal

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Enclosure

 

 

 

 

Condensate

Liquid

 

 

 

 

Return

 

 

 

 

Return

 

 

 

 

 

 

 

 

 

Tank

 

 

Liquid Return

 

Heater Terminal

 

 

 

 

Enclosure

Pump

 

 

 

 

 

 

 

 

 

 

 

Figure 1

 

 

Figure 2

 

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Chromalox PQ431 specifications General, Installation, Control Box Size, Accomplished By