Graco 3A0868G General Operating Cycle, Dynamic Dosing, Select a Component B Restrictor Size

Page 48

Setup Mode Details

Dynamic Dosing

In typical operation (ratios 1:1 and above), component A dispenses constantly. Component B dispenses intermit- tently in the necessary volume to attain the mix ratio.

General Operating Cycle, Dynamic Dosing

Overview

Dynamic Dosing provides on-demand proportioning, eliminating the need for an integrator and therefore min- imizing undesired material contact. This feature is espe- cially useful with shear-sensitive and waterborne materials.

A restrictor injects component B into a continuous stream of component A. The software controls the dura- tion and frequency of each injection. See FIG. 52 for a schematic diagram of the process.

Dynamic Dosing System Parameters

The following parameters affect dynamic dosing perfor- mance:

•Component A Flow: Ensure that the supply pump is sized to provide sufficient and uninterrupted flow. Note that component A provides majority of system flow at higher mix ratios.

•Component B Flow: Ensure that the supply pump is sized to provide sufficient and uninterrupted flow.

•Component A Pressure: Ensure precise pressure regulation. It is recommended that the component A pressure be 5-15% lower than the component B pressure.

•Component B Pressure: Ensure precise pressure regulation. It is recommended that the component B pressure be 5-15% higher than the component A pressure.

NOTE: When using dynamic dosing it is very important to maintain a constant, well-regulated fluid supply. To obtain proper pressure control and minimize pump pul- sation, install a fluid regulator on the A and B supply lines upstream of the meters.

Select a Component B Restrictor Size

If you cannot maintain the desired flow and spraying ratio, you may need to select a different restrictor. Use the charts on pages 61 to 65 to select an appropriate restrictor size based on the desired flow and mix ratio.

Balancing A/B Pressure

If component B pressure is too high, it will push the com- ponent A stream aside during B injection. The valve will not open long enough, causing a Ratio High error.

If component B pressure is too low, it will not be injected in sufficient volume. The valve will stay open too long, causing a Ratio Low error.

Selecting the correct component B restrictor size and balancing the A/B pressures will keep the system in the proper pressure range, resulting in a consistent mix ratio.

FIG. 50 shows the A to B pressure balance, read at the proportioner inlet. It is recommended that the compo- nent B pressure be 5-15% higher than the component A pressure to keep the system in the control range, hold the proper mix ratio, and obtain properly mixed material. If pressures are not balanced (“B Pressure Too High” or “B Pressure Too Low”), it may not be possible to hold the desired mix ratio. The system will generate an off ratio alarm and stop operation.

NOTE: In multi-flow rate systems, it is recommended that you set up the system to run properly at the highest flow rate, to ensure adequate fluid supply across the flow rate range.

In dynamic dosing, component A dose valve is con- stantly on. Component B dose valve will cycle on and off; one cycle every 0.5 – 1.0 seconds indicates proper balance.

Monitor system performance by watching the pressure readings for each pump on Run Pump Control (Screen 15).

FIG. 49. Monitor Pump Pressures

Warning messages also provide information on system performance. Adjust pressures accordingly. See Table 2 on page 49.

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3A0868G

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Contents ProMix 2KE Contents Models USBSeries Ratio Pumps Psi MPa, bar Port Approvals Related Manuals ModelsManual Description Fire and Explosion Hazard Special Conditions for Safe USEElectric Shock Hazard Intrinsic Safety Skin Injection HazardEquipment Misuse Hazard Moving Parts HazardToxic Fluid or Fumes Hazard Personal Protective EquipmentImportant Two-Component Material Information Glossary of Terms Installation OverviewUsage Component Identification and DefinitionIntrinsically Safe Installation Requirements Hazardous Location InstallationNon-Hazardous Locations Display Module Air SupplyRequirements Air regulator and bleed-type shutoff valveFluid Supply Air ConnectionsFluid Connections SVA DVA KeySVB DVB Tubing Chart and Diagrams Used only on is modelsGFB1-A ATOM-1 ATOM-2 Power Connection non-IS units only ElectricalGrounding Grounding Display Module DisplayIG . Display Module Key FunctionIcon Key Run Mode Setup ModeTroubleshooting Screen SummaryScreen User Input Range/Options Default Ranges for User InputsErrors Pump ControlHome RunSet-Up Home Password Configure RecipeMaintenance Calibration Set-Up HomeSystem Outputs Set-Up Home System Inputs System OutputsMembrane Test Power On Initial System SetupBasic Operation Pre-Operation TasksPrime the System Pump Calibration Calibrate the pumpSpraying PurgingBration 1 and 2 Screens 22 and 23, Purging Mixed Material Purging Fluid Supply SystemPurging Mixed Material Purging Fluid Supply SystemSolenoid Valves in Control Box Pressure Relief Procedure Valve SettingsLock Mode ShutdownError Log Use of Optional USB ModuleUSB Logs Job LogSetup Sample Error LogDownload Procedure Recommended USB Flash DrivesUSB Port Run Mode Details Run Mix Spray ScreenRun Home Screen Run Mix Batch ScreenRun Log Errors Screens Run Mix Totals ScreenRun Job Number Screen Run Pump Control Screen Run Pump Control ScreenSetup Mode Details Password ScreenSetup Home Screen Configure 1-4 Screens Confirm Change of System TypeConfigure 3 Screen 20 and Configure 4 Screen Recipe 1-1 Screen Recipe 1-2 ScreenMaintenance 1-3 Screens Maintenance RecommendationsRecommended Maintenance Component FrequencyTroubleshooting Screens Calibration 1 and 2 Screens 22Troubleshooting System Inputs Screen Troubleshooting System Outputs ScreenMembrane Test Screen Dynamic Dosing General Operating Cycle, Dynamic DosingSelect a Component B Restrictor Size Pressure Too High Pressure Too Low Pressure B Pressure B Control Range with Properly Sized RestrictorSystem Errors System AlarmsTo Clear Error and Restart Air Flow Switch AFS FunctionSystem Idle Warning Idle Error Codes System Alarm/Advisory/Record CodesAlarm Troubleshooting Alarm and Description Cause SolutionCommunication Error USB Communication ErrorEQU2 Alarm and Description Cause Solution SFA1 or SFB1 PreMix ErrorPneumatic Schematic, page 66 or PreFill ErrorRatio Low Error Already about equal, verify that comQDA1 QDB1Alarm and Description Cause Solution QTA1 or QTB1 Dose Time ErrorLeak Error Linear Sensor ErrorAlarm and Description Cause Solution DDA1 or DDB1 Diving/Cavitation ErrorPark Error Stall Up ErrorDynamic Dosing Restrictor Selection Graphs ExampleRestrictor Sizes Size Code Orifice Size Differential Pressure between a and B Flow Rate cc/min Detail View500 1000 1500 2000 2500 3000 3500 4000 200 14 150 10 100 7 50 3.4 500 1000 Psi 40 2.8 30 2.1 20 1.4 10 0.7 500 1000 Schematics System Pneumatic SchematicPneumatic Schematic Non-Hazardous LocationAIR Flow Switch SIG Hazardous Location Electrical Schematic Fluid J4CONTROL ModulePower Supply Non-Hazardous Electrical Schematic Dimensions and Mounting Merkur Merkur BellowsTechnical Data ProMix 2KE MetricOn-ratio accuracy Noise levelGraco Standard Warranty Graco Information
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