Technology Offers

A Novel High-Velocity Suspension Flame Spraying (HVSFS) Injector

Abstract

This novel and patent-pending HVSFS injector helps the operator to spray different solutions or suspensions independently, provides an adjustable spray cone and droplet size and also prevents blockage and coating interruption.

Advantages

  • Removable nozzle head: Quick replacement, residue-free nozzle
  • Nozzle heads with different geometries: Suitable to customised or specific process conditions
  • Significant reduction of the temperature at the injector tip
  • Independently spraying of two different supplied suspension or solution is possible
  • Saving time, costs, rework and significant improved quality of the final product

Fields of application

  • High velocity suspension flame spraying
  • Coating processes.

Background

As new materials and advanced manufacturing processes have been improved during the last decades, surface coating processes are developed as well. A high-quality and durable coated surface requires a strong bond between the coating materials and the target surface. HVSFS process provides a state-of-the-art, very thin, but finely structured coated layer(s), with low porosity and good adhesion on a surface, if an operator can manage this process without any interruption.

Problem

At the moment, the current HVSFS injectors cannot control the melting and evaporation of the suspension components easily, as undesired droplet and/or decay of the suspension or solution appears during the HVSFS spraying process. In scientific words, the liquid jet decays due to random turbulences inside the burner (torch).

In addition, the overheated injectors dry out the suspension solution, which usually ends in blockage of the injector. This blockage interrupts the process frequently and does not allow the operator to finish the work in one go (i.e. rework, wasted time and cost). Cleaning of such deposits that are trapped inside the nozzle head or inside the burner is also difficult and a burden for the operator, due to limited access to the inside of a spray gun.

Solution

Researchers at the Institute for Manufacturing Technology of Ceramic Components (IFKB) at the University of Stuttgart, Germany, have invented and fabricated a patent pending novel design of a HVSFS injector Spacing between " A dual-substance injector with an internal atomizer lance, which also might include separate channels for several fluids and an atomizing gas” This invention makes it possible to feed different types of suspensions/solution and the atomizing gas into the burner independently. Additionally, the improved design of the nozzle head helps the operator to control fluids’ atomization in the burner. Using this new design, the operator can change the shape of the spraying cone by tuning the nozzle contour.  Also, by varying the volume of the supplied atomizing gas, the droplet size could be optimised. As well, in order to support different process conditions, different nozzle heads with specific geometries are designed and realized.

This injector prevents plug formation and process interruptions due to overheating, as thermal decoupling of the nozzle head from the hot gas zone (i.e. the burner) is insured. Moreover, as the injector is connected to the burner via a coupling, the lance and nozzle head could be replaced and cleaned easily.

Figure 1: The patent pending and novel design of the injector (torch) for HVSFS processes   [Fig.: Gadow, Institute for Production Engineering of Ceramic Components, University of Stuttgart].
Figure 1: The patent pending and novel design of the injector (torch) for HVSFS processes [Fig.: Gadow, Institute for Production Engineering of Ceramic Components, University of Stuttgart].
Exposé
Contact
Dr. Hans-Jürgen Eisler
Technologie-Lizenz-Büro (TLB)
Ettlinger Straße 25
76137 Karlsruhe
Phone + 49 721 / 790 040
eisler(at)tlb.de | www.tlb.de
Development Status
TRL6-7 - Prototype developed
Patent Situation
CH 714521A2 pending
DE 102017130744.3 pending
FR 18/73324 pending
Reference ID
17/080TLB
Service
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