Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
  • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
  • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
  • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
  • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
  • F04C29/0092—Removing solid or liquid contaminants from the gas under pumping, e.g. by filtering or deposition; Purging; Scrubbing; Cleaning

Definitions

• the invention relates to a method for cleaning a dry-compression vacuum screw pump with internal compression
• Dry-compressing vacuum screw pumps with internal compression ie with non-isochoric compression, are operated without a lubricating, sealing and cleaning liquid.
• Certain condensate-rich, heavily loaded vacuum processes eg sintering or soldering, can lead to deposits on the pump rotors and / or the pump chamber. This increases the friction between the pump rotors and the pump chamber, so that the screw pump can finally start poor or not at all, significant vibration can occur during operation or a total loss of the screw pump can be caused. Therefore, the dry-compressing screw pump is cleaned regularly.
• the object of the invention is to provide a simple method for cleaning a dry-compressing vacuum screw pump with internal compression.
• the method according to the invention consists of the method steps
• the screw pump is operated for cleaning at its rated speed. A speed reduction for cleaning is not required. In this way, eliminates the technical effort for a speed reduction, which, depending on the nature of the electric drive motor, can be significant.
• the internal compression screw pump can be purged without any speed reduction at rated speed.
• the purge gas in the cleaning fluid ensures that the pressure increase in the pump chamber's pump chambers is moderate.
• the purge gas comes from a source other than the vacuum gas.
• the purge gas is not the gas that is pumped out of a vacuum container to create a vacuum. During the evacuation no evacuation takes place.
• the cleaning fluid is preferably mixed in a volume ratio of flushing liquid / flushing gas of at least 1: 100, preferably of at least 1: 1000.
• the mixing of the cleaning fluid with water as the rinsing liquid can be used, but tap water can also be used depending on the application. In any case, the flushing liquid water is inexpensive and available almost everywhere.
• the mixing of the cleaning fluid with air takes place as a purge gas.
• the ambient air can be used in most cases.
• the purge gas is thus available in a simple manner and inexpensively practically everywhere.
• the Spülga ⁇ has a pressure of at least 500 mbar, and may have approximately atmospheric pressure. The ambient air can therefore be used slightly throttled or unthrottled to mix the cleaning fluid.
• nitrogen and / or argon can be used as purge gas.
• Nitrogen and argon are less aggressive and are therefore suitable as purge gas in particularly sensitive applications or environments.
• a gas ballast valve of the screw pump is opened during the cleaning.
• the vacuum line leading to the gas inlet of the vacuum pump is closed before the introduction of the cleaning fluid, and after the completion of the cleaning fluid inlet, the vacuum line is opened again. In this way, penetration of the cleaning fluid into the Vakuumieitung or the connected vacuum vessel is reliably avoided.
• the figure shows schematically the structure of a system with a vacuum screw pump for operating the cleaning method according to the invention.
• a vacuum arrangement 10 which serves to evacuate a vacuum container 14.
• the vacuum container 14 may be part of a sintering system, a plasma CVD system or another system in which there is the possibility that the pumped by the screw pump 12 gas Contains components that can lead to deposits in the screw pump 12.
• the screw pump 12 has a gas inlet 16, which is connected with the interposition of valves 18,20,22 to the vacuum container 14, to a rinsing liquid container 24 and, if necessary, to a purge gas container 28.
• the screw pump 12 rotates at a speed of, for example, 8000 rpm.
• the vacuum valve 18 is opened while the other two valves 20, 22 are closed.
• the vacuum tank 14 is evacuated in this way.
• the screw pump 12 is regularly cleaned or rinsed after a specified period of operation.
• the vacuum valve 18 is closed so that the evacuation operation is interrupted. Subsequently, the purge gas valve 22 is opened, so that the purge gas, for example ambient air, is sucked by the screw pump 12.
• the purge gas for example ambient air
• a purge gas and nitrogen or argon can be used, which is stored in a corresponding Spülgas- container 28.
• the rinsing liquid valve 20 is opened, so that the rinsing liquid is sucked by the screw pump 12.
• Tap water is used as the rinsing liquid, but other liquids are also suitable.
• the purge gas and the purge liquid mix in front of the gas inlet 16 of the screw pump 12 to a cleaning fluid which is approximately from 0.2 to 3.0 l / min. Rinse fluid and approximately 4000 - 8000 standard liters / min. Purging gas exists. In the present case, approximately 1.0 liter per minute of rinse is mixed with the purge gas.
• the purge gas valve 22 the purge gas passes approximately at atmospheric pressure in the screw pump 12, but at least approximately 500 mbar.
• the total cleaning fluid consumption and the duration of the cleaning depends on the degree of contamination of the screw pump 12.
• the cleaning can be terminated when the color of the flushing fluid leaving the screw pump 12 is clear and no longer discolored. According to experience, between 3.0 and 8.0 liters of rinsing liquid are required for cleaning, so that cleaning takes a few minutes. After the actual cleaning process, the purge gas valve 22 remains open for a few minutes to ensure the fastest possible drying of the interior of the screw pump 12.
• the purge gas valve 22 remains open for 5 to 10 minutes in order to accelerate the drying of the interior of the screw pump 12.
• a gas ballast valve of the screw pump 12 if any, is opened. As a result, the drying is accelerated after the actual cleaning process.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Applications Or Details Of Rotary Compressors (AREA)
• Cleaning By Liquid Or Steam (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=35788773

Family Applications (1)

Country Status (6)

Cited By (4)

Families Citing this family (8)

Citations (5)

Family Cites Families (5)

• 2004
  • 2004-12-22 DE DE102004063058A patent/DE102004063058A1/de not_active Withdrawn
• 2005
  • 2005-12-05 KR KR1020077013187A patent/KR101280493B1/ko not_active Expired - Fee Related
  • 2005-12-05 DE DE502005009881T patent/DE502005009881D1/de not_active Expired - Lifetime
  • 2005-12-05 JP JP2007547437A patent/JP4819828B2/ja not_active Expired - Fee Related
  • 2005-12-05 US US11/793,631 patent/US20080135066A1/en not_active Abandoned
  • 2005-12-05 EP EP05815780.1A patent/EP1833622B2/de not_active Expired - Lifetime
  • 2005-12-05 WO PCT/EP2005/056489 patent/WO2006067032A1/de not_active Ceased

Patent Citations (5)

Non-Patent Citations (1)

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