Method and tool for cleaning cavities

• US 8,262,803 B2
• Filed: 06/02/2006
• Issued: 09/11/2012
• Est. Priority Date: 07/25/2005
• Status: Expired due to Fees

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Zorn, Christof, Grimme, Ralf
• Primary Examiner(s): Markoff, Alexander
• Application Number:
  US11/995,643
• Publication Number:
  US 20090107523A1
• Time in Patent Office: 2,293 Days
• Field of Search: 134/19, 134/22.1, 134/22.18, 134/22.12, 134/26, 134/30, 134/31, 134/34, 134/7, 134/6, 134/93, 134/105, 134/108, 134/8, 134/166.R, 134/167.R
• US Class Current: 134/22.18
• CPC Class Codes: B08B 7/0021 by liquid gases or supercritical fluids
• CPC Class Codes: B08B 9/00 Cleaning hollow articles by methods or apparatus specially adapted thereto B08B6/00 takes precedence
• CPC Class Codes: B23Q 11/005 by blowing
• CPC Class Codes: B23Q 11/0075 for removing chips or coolant from the workpiece after machining

Abstract

A method for cleaning cavities in workpieces, a cleaning device for this purpose and a device for the supply of media to a cleaning device of this type. Supercritical carbon dioxide is introduced into the cavity and the cavity is rinsed. The supercritical carbon dioxide located in the cavity is relieved of pressure after rinsing of the cavity, so that carbon dioxide gas and carbon dioxide snow are formed in the cavity and subsequently driven out of the cavity.

Claims

1. A method for cleaning cavities in workpieces, wherein in a first stage supercritical carbon dioxide being introduced into the cavity by means of a cleaning device and the cavity being rinsed with the supercritical carbon dioxide, and in a further stage the supercritical carbon dioxide located in the cavity being relieved of pressure after rinsing of the cavity so that carbon dioxide gas and snow are formed in the cavity and subsequently driven out of the cavity, wherein at least during the first stage a sealing between the cleaning device and the workpiece around the opening of the cavity is effected.

2. The method according to claim 1 wherein a further fluid is introduced into the cavity for blowing out the carbon dioxide snow.

3. The method according to claim 2 wherein at least one of a gas, gaseous, liquid and supercritical carbon dioxide, molecular nitrogen and compressed air is used as the further fluid.

4. The method according to claim 2 wherein at least one of gaseous, liquid and supercritical carbon dioxide is introduced as the further fluid such that further carbon dioxide snow is formed in the cavity.

5. The method according to claim 1 wherein the workpiece to be cleaned is heated.

6. The method according to claim 5 wherein the workpiece to be cleaned is heated with at least one of a furnace, a heating plate, a hot air blower and an IR radiator.

7. A device having a device for the supply of media to a cleaning device with fluid carbon dioxide as a cleaning medium, the device for the supply of media to a cleaning device with fluid carbon dioxide as a cleaning medium having a supply container for carbon dioxide, a fluid outlet which can be connected to the cleaning device and is connected to the supply container via a fluid pipe, a cooling unit which is disposed in the fluid pipe after the supply container, a high pressure pump which is disposed in the fluid pipe for producing a high operating pressure of the cleaning medium in the fluid pipe, a heating unit which is disposed in the fluid pipe after the cooling unit, and also a first controllable valve which is disposed in the fluid pipe, and a fluid bypass pipe around at least one of the pump and the heating device, said bypass pipe having a second controllable valve and said bypass pipe allowing CO₂, to be introduced into the cleaning device without passing the at least one of the pump and the heating device, the device further having the cleaning device for cleaning a cavity in workpieces with an inlet and an outlet for a cleaning medium, the inlet being connected to the device for the supply of media, the cleaning device having a lance having at least one outlet element which is suitable for introducing supercritical, liquid or gaseous CO₂, into the cavity to be cleaned and converting it there into CO₂ snow as a CO₂ jet, the cleaning device further having a seal surrounding the lance.

8. The device according to claim 7 wherein the bypass pipe includes a first end and a second end, and is connected by its first end at a first connection point in front of at least one of the pump and the heating device to the fluid pipe and, is connected by its second end, at a second connection point behind at least one of the pump and the heating device to the fluid pipe.

9. The device according to claim 8 wherein the first valve is disposed in the fluid pipe between the first and the second connection point.

10. The device according to claim 7 further including a seal for sealing between the outlet and the workpiece to be cleaned.

11. The device according to claim 7 wherein the outlet has at least one outlet element for the cleaning medium.

12. The device according to claim 7 wherein the lance has outlet elements in the region of its end in at least one of the axial direction and the lateral direction on its surface which extends along the axis thereof.