Graco 309524N Determining Proper Fluid Temperature, To find your fluid’s Under-Boil temperature

Page 12

Installation

Determining Proper Fluid Temperature

CAUTION

Operating the heater at its highest setting, over 180°F (82°C), for long periods of time decreases the heater life and can cause fluid to dry out; which can clog the heater and result in a poor finish.

Use the lowest temperature setting possible for maxi- mum heater life. Use the chart in FIG. 9 to determine the

Under-Boil®temperature. FIG. 9 also shows the effect of temperature on reducing viscosity. Note that most of the viscosity reduction occurs by 130°F (55°C).

Under-Boil is the Graco method of hot, airless spraying where the fluid is heated to a temperature just under the boiling point of its most volatile solvent.

To find your fluid’s Under-Boil temperature:

1.Pour a small sample into a heat-proof container.

2.Measure and record the fluid temperature and vis- cosity using a No. 2 Zahn cup.

3.Heat water in a large container to 200°F (93°C). Place the sample in the water.

4.At every 10° temperature rise, measure and record the viscosity and temperature. Do this until solvents start boiling off and the viscosity starts to level off, usually 160-170°F (71-77°C).

5.To find the temperature to use in your Under-Boil system:

a.Subtract the lowest viscosity reading from the highest one.

b.Multiply the result by 0.90.

c.Subtract the result from the highest viscosity reading. Find this number on your temperature and viscosity records.

 

100

 

 

 

 

 

 

 

 

 

 

 

 

 

90

 

 

 

 

 

 

 

 

 

 

 

 

cup

80

 

 

 

 

Heavy Lacquer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Zahn

70

 

 

 

 

 

Medium Lacquer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

#2

60

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

with

 

 

 

 

 

 

Enamel

 

 

 

 

 

50

 

 

 

 

 

 

 

 

 

 

 

 

seconds

40

 

 

 

 

 

 

 

 

 

 

 

 

30

 

 

 

 

 

 

 

 

 

 

 

 

Viscosity:

 

 

 

 

 

 

 

 

 

 

 

 

20

 

 

 

 

 

 

 

 

 

 

 

 

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

oC

 

20

 

30

 

40

50

 

60

 

70

 

80

 

(70)

(80)

(90)

(100)

(110)

(120)

(130)

(140)

(150)

(160)

(170)

(180) (oF)

 

 

 

 

 

 

Temperature

 

 

 

 

 

 

FIG. 9: Reducing Viscosity: Under-Boil Method

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309524N

Image 12
Contents Viscon HP Hazardous Location Heater shownModels Hazardous Location HeatersNon-hazardous Location Heaters ApprovalsContents TranslationsManual Conventions Skin Injection Hazard Equipment Misuse Hazard Installation Typical Installation DrawingKey Chart Notes Selecting TubingMounting Heater Wall MountingBracket Fluid Connections Accessories Cart MountingRequirements For All Installations Hazardous Location Installation RequirementsElectrical Connections Wall Mounted Wiring Cart Mounted WiringGrounding Determining Proper Fluid Temperature To find your fluid’s Under-Boil temperatureEffect of Temperature on Viscosity Pressure Relief Procedure OperationInitial Flushing Priming SystemSetting Heater Control Adjusting for SprayingRefer to FIG Maintenance Follow Pressure Relief Procedure,Flushing Unclogging Fluid PassagesTroubleshooting Problem Cause SolutionBackup Thermostat Reassembly NotesRepair Primary Thermostat & ProbeThermostat Repair Hazardous Location Heaters Thermal Limit Sensor Control KnobHeater Block Control Repair Hazardous Location Heaters Parts Hazardous Location HeatersRef. No Heater Block Series Volts / Watts Part No. Description QtyNon-Hazardous Location Heaters Enclosure Accessories Cable Clamp Kit 246303 Installation Cable Clamp Kit KeyTechnical Data Maximum Temperature Rise vs. Flow RateDimensions Graco Standard Warranty For Graco Canada Customers