Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
  • B24C7/00—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts
  • B24C7/0084—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts the abrasive material being fed in a mixture of liquid and gas
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
  • B24C11/00—Selection of abrasive materials or additives for abrasive blasts
  • B24C11/005—Selection of abrasive materials or additives for abrasive blasts of additives, e.g. anti-corrosive or disinfecting agents in solid, liquid or gaseous form
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
  • B24C7/00—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts
  • B24C7/0046—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts the abrasive material being fed in a gaseous carrier

Definitions

• the invention relates to a method for compressed air blasting, in which a granular abrasive is introduced into a carrier air stream and conveyed by the carrier air stream, accelerated and blown against a surface to be treated, and a supplementary air stream loaded with a liquid additive wetting the grains of the blasting agent, in particular water is added with the air stream loaded with the blasting agent, in particular injected into the air stream loaded with the blasting agent.
• a method for compressed air blasting in which a granular abrasive is introduced into a carrier air stream and conveyed by the carrier air stream, accelerated and blown against a surface to be treated, and a supplementary air stream loaded with a liquid additive wetting the grains of the blasting agent, in particular water is added with the air stream loaded with the blasting agent, in particular injected into the air stream loaded with the blasting agent.
• wet blasting In the known method for compressed air blasting described above, so-called wet blasting is sought; the individual grains of the blasting medium should be coated with the additive in such a way that the dust which develops when it hits the surface to be treated due to bursting grains of the blasting medium is bound.
• the aim of the known process is thus a process formerly known as sandblasting and now often known as free blasting, which is neither dry blasting nor wet blasting due to the coating of the grains of the blasting medium with the additive, but rather is to be found in the intermediate area between the two processes.
• the addition of the additive, in particular water, is carried out in such a way that, on the one hand, the coating of the individual grains of the blasting medium has practically evaporated after impact, so that no additive runs off, but on the other hand the low coating of the grains of the blasting medium is sufficient to prevent dust formation largely suppressed, so that contributes to occupational safety because the risk of the typical occupational disease dust lung is significantly reduced.
• the known method is characterized by a low water consumption and can therefore be used like the known dry blasting - sandblasting with dry sand - because discharge devices for water or the like are not required.
• the object of the invention is therefore to design and further develop the known method in such a way that, with the lowest consumption of liquid additive, the most uniform and uniform moistening of all the grains of the blasting agent in the entire jet is achieved.
• a precisely metered coating of each individual abrasive grain, regardless of its location in the air flow, is aimed for.
• the method according to the invention in which this object is achieved, is initially characterized in that the back pressure of the additional air flow in the injection region is approximately one and a half to two and a half times, preferably twice as high as the back pressure of the carrying air flow.
• the above-mentioned dynamic pressure difference between the additional air flow and the air flow ensures that the liquid additive penetrates deep enough into the air flow on the one hand, but on the other hand does not shoot through the air flow and is not only reflected on the inner wall of the blasting device used.
• a good atomization of the liquid additive is achieved in the specified parameter range; the desired low water consumption is achieved.
• the dust binding proves to be very cheap.
• the total pressure of a flowing medium is made up of the static pressure and the dynamic pressure.
• the back pressure is known to be the measure of the kinetic energy of the flowing medium, i.e. a direct measure of the flow velocity.
• sufficient mixing of the air flow and the additional air flow is achieved, which leads to the desired takeover of the liquid additive by the grains of the blasting medium.
• the focus has been on the dynamic pressures and thus indirectly on the speeds of the air flow and the additional air flow, but not on the actual speeds of the grains of the abrasive or the liquid additive.
• these speeds are always below the speed of the carrying air flow or additional air flow carrying them, so that the desired mixing results.
• the mass of abrasive supplied to the injection area in the time unit is approximately 1.4 to 2.5 times, in particular 1.7 to 2.2 times, the mass supplied to the injection area in the time unit Air corresponds to.
• the mass of additive, in particular water, supplied to the injection area in the time unit corresponds to approximately 2 o to 3 o, preferably d 6, of the mass of carrier air supplied to the injection area in the time unit.
• This mass of additive is sufficient, on the one hand, to be able to moisten the grains of the abrasive sufficiently in the entire cross-section of the air flow, but on the other hand it is not so high that excess, liquid additive is produced, which is either deposited in the blasting device or on the surface to be treated and must be dissipated.
• the consumption of liquid additive for example water, remains limited.
• the moistening of the grains of the blasting agent is improved by an additional relative movement between the grains of the blasting agent and the finely divided additive. This can be done by eccentrically introducing the air flow into the additional air flow; the grains of the blasting medium can be set in rotary movements, in particular in helical movements, or can also undergo their own rotation.
• a device as described in DE-A No. 2724318 is suitable for carrying out the method described above.
• the disclosure content of this document is expressly made the disclosure content of the present patent application.
• the grains of the blasting medium are still slow and therefore only move a short distance during the time required for moistening. This enables even moistening to be achieved.
• the suction effect in the smallest nozzle cross-section is not necessary anyway, because the additional air flow is fed with excess pressure.
• the dynamic pressure of the additional air flow is typically in the range from 10 to 30 bar. Satisfactory results were achieved with these pressure values.
• blasting media can only be introduced into a nozzle area if there is at the same time an additional air stream sufficiently loaded with additive.
• Even in the event of operating errors it is not possible to work without adding the liquid additive, in particular, therefore, to work with dry abrasive.
• the occupational safety achieved by wet blasting is always set and cannot be switched off due to operating errors.
• the forced coupling also ensures that the additional air flow is sufficiently loaded with the liquid additive in order to be able to adequately bind the accumulated dust quantities.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Nozzles (AREA)
• Sorption Type Refrigeration Machines (AREA)
• Jet Pumps And Other Pumps (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=6136450

Family Applications (1)

Country Status (8)

Families Citing this family (27)

Family Cites Families (19)

• 1981
  • 1981-07-09 DE DE19813127035 patent/DE3127035A1/de not_active Withdrawn
• 1982
  • 1982-06-18 AT AT82105335T patent/ATE12196T1/de active
  • 1982-06-18 EP EP82105335A patent/EP0069874B1/de not_active Expired
  • 1982-06-18 DE DE8282105335T patent/DE3262640D1/de not_active Expired
  • 1982-06-23 GR GR68524A patent/GR76183B/el unknown
  • 1982-06-30 KR KR1019820002930A patent/KR840000284A/ko not_active Withdrawn
  • 1982-07-05 PT PT75183A patent/PT75183B/pt not_active IP Right Cessation
  • 1982-07-06 US US06/395,619 patent/US4802312A/en not_active Expired - Fee Related
  • 1982-07-07 JP JP57117046A patent/JPS5871065A/ja active Pending

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