POLYUREA SPRAY EQUIPMENT Prerequisite to make your Polyurea job Successful Presenter: Authors: Stephan Rindfleisch C.Royo, S. Rindfleisch, H. Mann
APPLICATION REQUIREMENTS 2 Component System Spray Pressure between 150 and 240 Bar Temperatures between 65 and 80 C Flow Rates between 2 and 10 liter/minute* *for typical coating applications
EQUIPMENT REQUIREMENTS Meter and Mix the chemicals at the right mixing ratio Capability to produce and maintain the required operating pressure Achieve enough Delta T (Temperature Rise) to heat up the chemicals to the application temperature at required pressure and flow rate Deliver the desired flow rate at required pressure
EQUIPMENT OVERVIEW Feed system for 200 liter drums Proportioning and Heating unit Heated hose Spray gun
FEED SYSTEMS Feed pumps are required to bring enough material at the right pressure to the dosing unit Available technologies: Double acting piston pumps Double Diaphragm pumps
FEED SYSTEMS The feed systems is a key component of the system setup to transfer the chemicals from the drums to the machine. Special attention is required to select the proper pump for the application to meet the viscosity and storage temperature of the chemicals. Agitation is required on the Resin side to avoid sedimentation of material (color pigments, fillers) A wrong selected feed pump can cause major issues with the application by not delivering the chemicals at the right pressure or the right flow rate to the machine
PROPORTIONING SYSTEMS There are 3 different technologies for fixed ratio proportining systems available: Air operated systems Direct electrical driven systems Electro-Hydraulic driven systems
PROPORTIONING SYSTEMS Air operated systems: One air motor drives 2 (or more) positive displacement pumps which meter the chemicals and create the necessary spray pressure
PROPORTIONING SYSTEMS
PROPORTIONING SYSTEMS Direct Electric operated systems: One electric motor with drive shafts on either end, drives 2 positive displacement pumps which meter the chemicals and create the necessary spray pressure
PROPORTIONING SYSTEMS
PROPORTIONING SYSTEMS Electro Hydraulic Driven systems: One electric motor drives a hydraulic pump to operate a hydraulic motor with 2 displacement pumps which meter the chemicals and create the necessary spray pressure
PROPORTIONING SYSTEMS Hydraulic pump operation
PROPORTIONING SYSTEMS variable ratio There are different technologies for variable ratio proportining systems available: Mechanical Electronic
PROPORTIONING SYSTEMS variable ratio, mechanical The Air driven and hydraulic driven proportioning systems can be modified to operate at mixing ratios other than 1:1 The dosing pumps on these units can be changed to different sizes to match the desired ratio up to 10:1
PROPORTIONING SYSTEMS variable ratio, electronic An electronically variable ratio system also available: By using two independant hydraulic circuits and a control system, the machine can achieve mixing ratios from 1:1 up to 10:1
Fluid Heaters To achieve the necessary Delta T (Temperature rise) at the desired flow rate, the fluid heaters are key element of the application. There are 3 main versions of heating systems: Mass heater Immersion (Direct contact heating) Hybrid All of these types work fine, as long as the Delta T is achieved
Heater schematics Pressure gauge Heating element Fluid outlet Pressure switch Temperature sensor Mass Block Pressure switch Fluid Inlet
Heated Hoses Heated hoses are needed to maintain the temperature of the chemicals coming from the heater. With the exception of the start up, heated hose are not used to heat up material but to maintain temperature. Hoses are typically low voltage types and are temperature controlled with a sensor inside one of the lines of the 2 components.
Impingement Mix guns Due to the extreme short reaction time of Polyurea, only impingement mix guns can be used There are different Technologies available Air Purge gun Mechanical Purge gun (aka Needle gun)
Impingement Mix guns Air Purge An Air Purge gun uses a metal mixing chamber with 2 orifices for the chemicals and an outlet to exit the mixing chamber. At each of the orifices a valve (side seal) is used to open or close the fluid flow to the mixing chamber. When the gun is triggered, the 2 components will flow through the mixing chamber and Polyurea is sprayed to the surface. When the gun is de-triggered, fluid flow stops and pressurized air will flow through the orifices and clean out the mixing chamber = Air Purge
Impingement Mix guns Air Purge AIR PURGE GUN OPERATION:
Impingement Mix guns Mechanical Purge A Mechanical Purge gun uses a mixing module with 2 orifices for the chemicals and an outlet to exit the mixing module to an atomizing tip. A needle is used to open or close the two orifices of the mixing module. When the gun is triggered, the 2 components will flow through the mixing module and Polyurea is sprayed to the surface. When the gun is de-triggered, fluid flow stops and the needle will push out all mixed material from the module = Mechanical Purge
Impingement Mix guns Mechanical Purge
Impingement Mix guns Air Purge
Impingement Mix guns Mechanical Purge
Conclusion Application of Polyurea requires a complete system setup to match the chemicals specification. Feed System Proportioning and Heating System Heated Hoses Spray gun All components need to be selected properly to fit the needed application requirements on flow, temperature and pressure.
Conclusion Training is another key element for a successful Polyurea application Training on how to use the equipment Provided by the machine manufacturer (or its distributor) Application training See Applicator training from PDA-Europe (www.pda-europe.org)
Disclaimer Credits This presentation contains materials and copyright content from the following companies: GAMA, Spain Graco, Belgium WiWa, Germany
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