WO2016112439A1 - Élément de pompe à vide à injection d'huile - Google Patents

Élément de pompe à vide à injection d'huile Download PDF

Info

Publication number
WO2016112439A1
WO2016112439A1 PCT/BE2016/000002 BE2016000002W WO2016112439A1 WO 2016112439 A1 WO2016112439 A1 WO 2016112439A1 BE 2016000002 W BE2016000002 W BE 2016000002W WO 2016112439 A1 WO2016112439 A1 WO 2016112439A1
Authority
WO
WIPO (PCT)
Prior art keywords
compression chamber
lib
oil
vacuum pump
connection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/BE2016/000002
Other languages
English (en)
Other versions
WO2016112439A8 (fr
Inventor
Jens BOECKX
Jozef Maria Segers
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Atlas Copco Airpower NV
Original Assignee
Atlas Copco Airpower NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from BE2015/5137A external-priority patent/BE1022764B1/nl
Priority to CN201680005798.6A priority Critical patent/CN107208640B/zh
Priority to EP16709692.4A priority patent/EP3245405B2/fr
Priority to BR112017014897-8A priority patent/BR112017014897B1/pt
Priority to US15/542,326 priority patent/US10670014B2/en
Priority to CA2972636A priority patent/CA2972636C/fr
Application filed by Atlas Copco Airpower NV filed Critical Atlas Copco Airpower NV
Priority to JP2017537447A priority patent/JP6716576B2/ja
Priority to RU2017128874A priority patent/RU2689224C2/ru
Publication of WO2016112439A1 publication Critical patent/WO2016112439A1/fr
Publication of WO2016112439A8 publication Critical patent/WO2016112439A8/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • F04C25/00—Adaptations of pumps for special use of pumps for elastic fluids
    • F04C25/02—Adaptations of pumps for special use of pumps for elastic fluids for producing high vacuum
    • 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
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/06—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids specially adapted for stopping, starting, idling or no-load operation
    • 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
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/24—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F04C28/26—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels

Definitions

  • the present invention relates to an oil-injected vacuum pump element.
  • the invention is intended for oil- injected vacuum pump elements of the screw type, whereby two cooperating helical rotors are rotatably provided in a housing.
  • Chambers are defined between the lobes of the helical rotors and the walls of the housing, that move from the inlet side to the outlet side as a result of the rotation of the rotors and thereby become increasingly smaller so that the air trapped in these chambers is compressed.
  • This oil originates from an oil separator where the oil is separated from the outlet air.
  • This air content can be in the oil in the form of air bubbles or dissolved therein. As a result there is a risk of cavitation.
  • cavitation In an oil flow there are two types of cavitation:
  • Such cavitation can occur in an oil-injected vacuum pump element of the screw type under the influence of a fall of the static pressure, more specifically at the outlet of the vacuum pump in the last phase of compression.
  • the volume of the compression chamber goes to zero, such that the pressure in this chamber can rise above the outlet pressure.
  • large pressure differences occur between the aforementioned chamber and the inlet, where the pressure can be 0.3 mbar(a) and below.
  • the aforementioned chamber is separated from another compression chamber that connects to the inlet by only one single section of the rotor profiles.
  • a type of channel forms between the profiles of the rotors or between the rotors and the outlet end face that first converges and then diverges to form a 'nozzle' .
  • a leakage flow of gas and oil is possible through this channel from the aforementioned chamber to the inlet due to the large pressure difference between the two, whereby due to the form of the channel and the rotors the speed of this leakage flow becomes so high that the static pressure becomes so low that gas bubbles can form.
  • the purpose of the present invention is to provide a solution to the aforementioned and other disadvantages.
  • the subject of the present invention is an oil-injected vacuum pump element of the screw type, whereby two cooperating helical rotors are rotatably provided in a housing, whereby this housing comprises an inlet port, an inlet end face and an outlet end face with an outlet port, whereby compression chambers are formed between the helical rotors and the housing that proceed from the inlet port to the outlet port due to the rotation of the helical rotors and thereby become increasingly smaller, whereby the oil- injected vacuum pump element is provided with a connection that extends from a first compression chamber to a second smaller compression chamber at the outlet end face, whereby this first compression chamber is at a lower pressure than the second compression chamber and whereby this second compression chamber can make connection with the outlet port upon rotation of the helical rotors, whereby the connection is such that a flow from the second compression chamber to the first compression chamber is possible so that the pressure in the second compression chamber is
  • the first compression chamber Due to the rotation of the helical rotors the first compression chamber will become increasingly smaller and finally becomes the second compression chamber, whereby at this time a new first compression chamber is formed.
  • the second compression chamber is the compression chamber at the end of the compression cycle, in which there is compressed gas that can then leave the vacuum pump element via the outlet port. It goes without saying that this second compression chamber is not connected to the inlet port .
  • An advantage of an oil-injected vacuum pump element according to the invention is that the pressure difference between the inlet and the second compression chamber is reduced because a flow of gas and oil is made possible via the connection from the second compression chamber at a higher pressure to the first compression chamber at a lower pressure .
  • cavitation can be prevented because the flow via the channel between the profiles of the helical rotors or the flow between the rotors and the outlet end face in the section of the rotor profiles that separates the aforementioned second compression chamber from the compression chamber that is connected to the inlet, will have a much lower speed.
  • connection The precise location of the connection and the design thereof will depend on the profile of the helical rotors and the shape and location of the outlet port. Both can differ strongly depending on the vacuum pump element concerned .
  • connection comes into contact with the outlet port, i.e. the connection must not connect directly to the outlet port .
  • figure 1 schematically shows an oil-injected vacuum pump element of the screw type
  • figure 2 schematically shows a cross-section of the oil-injected vacuum pump element of figure 1 along the line II-II of figure 1;
  • figure 3 shows a similar cross-section to figure 2, but of an oil-injected vacuum pump element according to the invention
  • figure 4 shows the cross-section of figure 3, but in a different position of the helical rotors
  • the oil-injected vacuum pump element 1 shown in figure 1 is an element of the screw type.
  • the element 1 essentially comprises a housing 2 in which two cooperating helical rotors 3 are rotatably provided.
  • the housing 2 comprises an inlet end face 4 on the inlet side 5 and an outlet end face 6 on the outlet side 7.
  • An inlet port 8 is affixed in the housing 2. This inlet port 8 is indicated by a dashed line in figure 1.
  • An outlet port 9 is affixed in the housing at the location of the outlet end face 6. This is shown in figure 2. Compression chambers 11a, lib are formed between the lobes 10 of the helical rotors 3 and the housing 2. Due to the rotation of the helical rotors 3 these compression chambers 11a, lib move from the inlet port 8 to the outlet port 9.
  • Air that gets into a compression chamber 11a via the inlet port 8 in the first compression phase is transported to the outlet port 9 by the rotation of the helical rotors 3 and is thereby compressed to a higher pressure.
  • the compression chamber lib will makecontact with the outlet port 9 so that the compressed air in this compression chamber lib can be removed during the last compression phase.
  • the accompanying compression chambers 11a, lib that belong to the two aforementioned compression phases, i.e. a first compression chamber 11a that makes contact with the inlet port 8 and the outlet end face 6 and a second compression chamber lib that only makes contact with the outlet end face 6 but not with the inlet port 8 or the inlet end face 4 , are indicated in figure 2.
  • these two compression chambers 11a, lib are separated from one another by one single section of the helical rotors 3, whereby a channel 12 with a "nozzle" shape is formed between the profiles of the helical rotors 3.
  • a flow of air and/or oil is possible via this channel 12 in the direction from the second compression chamber lib to the first compression chamber 11a, whereby due to the form of the channel 12 the flow speed becomes so high that cavitation can occur.
  • connection is affixed in the outlet end face, in this case in the form of a groove 13.
  • This groove 13 extends from the first compression chamber 11a to the second compression chamber lib.
  • a first end 14a of the groove 13 will at least partially overlap the first compression chamber 11a and a second end 14b of the groove 13 will overlap the second compression chamber lib.
  • the groove 13 makes contact with a first compression chamber 11a that is connected to the inlet port 8, this is not necessarily the case. It is only necessary for the invention that the first compression chamber 11a concerned, to which the groove 13 is connected, is at a lower pressure than the second compression chamber lib. According to the invention the connection is designed such that the groove 13 is not directly connected to the outlet port 9.
  • the groove 13 stops at some distance from the outlet port 9 so that there is no contact with the second end 14b of the groove 13 and the outlet port 9.
  • Figure 4 shows the situation whereby the volume of the second compression chamber lib has gone to practically zero. Hereby the second end 14b of the groove 13 is still connected to the second compression chamber lib.
  • the location of the second end 14b, by which the groove 13 makes contact with the second compression chamber lib, must be suitably chosen such that a connection to the second compression chamber lib is realised without coming into contact with the outlet port 9.
  • the final form and size of the groove 13 and thus the flow rate of gas and/or oil that can flow via the groove 13 will depend on two criteria: the flow rate must be high enough so that the pressure in the second compression chamber lib can fall enough to prevent cavitation;
  • the flow rate may not be too high because in this case the performance or efficiency of the oil-injected vacuum pump element 1 will fall.
  • the flow rate that can flow via the groove 13 will depend on the minimum cross-section of the groove 13.
  • this minimum cross-section of the groove 13 in mm 2 is between 0.01 and 0.04 times the maximum volumetric flow of the element 1 in litres per second.
  • this minimum cross-section in mm 2 is between 0.01 and 0.1 or 0.01 and 0.08 or 0.01 and 0.06 times the maximum volumetric flow of the element 1 in litres per second.
  • a groove 13 with a smaller minimum cross-section will not be able to allow sufficient flow to let the pressure in the second compression chamber lib fall enough to prevent cavitation .
  • a groove 13 with a larger minimum cross-section will allow through the large flows from the second compression chamber lib to the first compression chamber 11a, such that the efficiency of the oil-injected vacuum pump element 1 will fall by too much.
  • the end 14b of the groove 13 that is connected to the second compression chamber lib at the outlet end face 6 is designed such that the maximum contact area between the groove and the aforementioned compression chamber lib has an area in mm 2 between 0.01 and 0.04 times the maximum volumetric flow of the element 1 in litres per second . It is not excluded that the aforementioned maximum contact area is between 0.01 and 0.1 or 0.01 and 0.08 or 0.01 and 0.06 times the maximum volumetric flow of the element 1 in litres per second. As it is possible that the contact area between the groove 13 and the second compression chamber lib is less than the minimum cross-section of the groove 13 itself, preferably it is sufficient for the aforementioned contact area to be at the higher stated condition, in order to obtain the desired effect. Different options are possible with regard to the final design of the groove 13.
  • the groove comprises at least one slot-shaped section 15.
  • Slot-shaped 15 section here means a part of the groove 13 whose cross-section, viewed in the flow direction through the groove 13, does not change or practically does not change.
  • This section 15 can be straight or curved.
  • the groove 13 only comprises a slot- shaped section 15.
  • the slot-shaped groove 13 has different orientations. It is also possible that the groove 13 connecting to this slot-shaped section 15 comprises a broadened section 16, whereby the groove 13 at least partially overlaps the first compression chamber 11a. This is shown in figure 7, where it can be seen that the first end 14a of the groove 13 is formed by a broadened section 16 with a wider cross-section than the second end 14b that is formed by a slot-shaped section 15. The precise shape of this broadened section 16 is of secondary importance. The only condition for the first end 14a is that this end 14a extends far enough so that the groove 13 is always connected to the first compression chamber 11a.
  • the overlap between the groove 13 and the first compression chamber 11a is such that the connection between the first compression chamber 11a and the second compression chamber lib is preserved by means of the groove 13 upon the rotation of the helical rotors 2 until the volume of the second compression chamber lib goes to zero.
  • connection is always made by means of a groove 13 in the outlet end face 6, it is not excluded that the connection is realised by means of a groove part in the outlet end face 6 that at least partially overlaps the second compression chamber lib and a channel or pipe connected thereto that leads to a first compression chamber 11a at a lower pressure than the second compression chamber lib.
  • this compression chamber 11a can be the compression chamber 11a that is connected to the inlet port 8, but this is not the necessary for the invention.
  • This channel or this pipe can be built in housing itself or otherwise, but of course can also be constructed on the housing .
  • this minimum cross-section of the groove part and the channel and the maximum contact area between the groove part and the second compression chamber lib both satisfy the above-mentioned conditions i.e. this minimum cross- section and this maximum contact area in mm 2 is between 0.01 and 0.1 times the maximum volumetric flow of the element 1 in litres per second, and preferably between 0.01 and 0.08 times, even better between 0.01 and 0.06 times, and even more preferably between 0.01 and 0.04 times.
  • the aforementioned groove part can take on the form of the slot-shaped section 15 of the groove 13 for example, as shown in figure 7.
  • the channel or the pipe is such that the connection between the first compression chamber 11a and the channel or the pipe is preserved upon rotation of the helical rotors 3 until the volume of the second compression chamber lib goes to zero.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Rotary Pumps (AREA)

Abstract

L'invention concerne un élément de pompe à vide à injection d'huile. Selon l'invention, deux rotors hélicoïdaux coopérants (3) sont disposés en rotation dans un boîtier (2), ce boîtier (2) comprenant un orifice d'entrée (8) et une face d'extrémité de sortie (6) pourvu d'un orifice de sortie (9). Des chambres de compression (11a, lib) sont formées entre les rotors hélicoïdaux (3) et le boîtier (2). L'invention est caractérisée en ce que l'élément de pompe à vide (1) comporte une liaison qui s'étend à partir d'une première chambre de compression (11a) jusqu'à une seconde chambre de compression plus petite (lib) au niveau de la face d'extrémité de sortie (6), cette première chambre de compression (11a) étant à une pression inférieure à celle de la seconde chambre de compression (lib) et cette deuxième chambre de compression (lib) pouvant établir une liaison avec l'orifice de sortie (9) lors de la rotation des rotors hélicoïdaux (3). La liaison est telle qu'un écoulement à partir de la deuxième chambre de compression (lib) jusqu'à la première chambre de compression (11a) est possible, la liaison n'étant pas directement reliée à l'orifice de sortie (9).
PCT/BE2016/000002 2015-01-15 2016-01-07 Élément de pompe à vide à injection d'huile Ceased WO2016112439A1 (fr)

Priority Applications (7)

Application Number Priority Date Filing Date Title
RU2017128874A RU2689224C2 (ru) 2015-01-15 2016-01-07 Винтовой элемент вакуумного насоса с масляным уплотнением
EP16709692.4A EP3245405B2 (fr) 2015-01-15 2016-01-07 Élément de pompe à vide à injection d'huile
BR112017014897-8A BR112017014897B1 (pt) 2015-01-15 2016-01-07 Elemento de bomba de vácuo injetado com óleo
US15/542,326 US10670014B2 (en) 2015-01-15 2016-01-07 Oil-injected vacuum pump element
CA2972636A CA2972636C (fr) 2015-01-15 2016-01-07 Element de pompe a vide a injection d'huile
CN201680005798.6A CN107208640B (zh) 2015-01-15 2016-01-07 喷油真空泵元件
JP2017537447A JP6716576B2 (ja) 2015-01-15 2016-01-07 オイル噴射式真空ポンプ要素

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201562103772P 2015-01-15 2015-01-15
US62/103,772 2015-01-15
BE2015/5137 2015-03-12
BE2015/5137A BE1022764B1 (nl) 2015-01-15 2015-03-12 Oliegeïnjecteerde vacuümpomp element

Publications (2)

Publication Number Publication Date
WO2016112439A1 true WO2016112439A1 (fr) 2016-07-21
WO2016112439A8 WO2016112439A8 (fr) 2016-09-09

Family

ID=55527181

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/BE2016/000002 Ceased WO2016112439A1 (fr) 2015-01-15 2016-01-07 Élément de pompe à vide à injection d'huile

Country Status (2)

Country Link
RU (1) RU2689224C2 (fr)
WO (1) WO2016112439A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989012752A1 (fr) * 1988-06-17 1989-12-28 Svenska Rotor Maskiner Ab Compresseur de type volumetrique rotatif et installation de refrigeration
WO2006095364A1 (fr) * 2005-02-02 2006-09-14 Elgi Equipmetns Ltd Systeme et procede pour le controle de la capacite dans un comresseur a vis

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1248031A (en) * 1967-09-21 1971-09-29 Edwards High Vacuum Int Ltd Two-stage rotary vacuum pumps
RU97776U1 (ru) * 2008-08-28 2010-09-20 Общество с ограниченной ответственностью "Уральский центр инновационных технологий" Роторная винтовая машина
CN202468326U (zh) * 2012-02-23 2012-10-03 台州市星光真空设备制造有限公司 一种真空泵

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989012752A1 (fr) * 1988-06-17 1989-12-28 Svenska Rotor Maskiner Ab Compresseur de type volumetrique rotatif et installation de refrigeration
WO2006095364A1 (fr) * 2005-02-02 2006-09-14 Elgi Equipmetns Ltd Systeme et procede pour le controle de la capacite dans un comresseur a vis

Also Published As

Publication number Publication date
RU2689224C2 (ru) 2019-05-24
RU2017128874A3 (fr) 2019-02-15
WO2016112439A8 (fr) 2016-09-09
RU2017128874A (ru) 2019-02-15

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