Method for Operating a Vacuum Pump, as well as a Vacuum Pump Designed for this Purpose with Two Inlets and One Outlet, its Use and Vacuum Packaging Machines Equipped Therewith

Abstract

The present invention relates to a method for evacuating at least two external vacuum chambers i and j ( 20, 20′ ) with a vacuum pump ( 10 ), in particular a rotary vane vacuum pump ( 10 ), whereby the vacuum chamber i ( 20 ) is evacuated from the initial pressure p 02(i) to a final pressure p 12(i) via the second inlet ( 2 ) during an evacuation time t p2(i) and at the same time the vacuum chamber j ( 20 ) is evacuated via the first inlet ( 1 ) from the initial pressure p 01(j) to a final pressure p 11(j) during an evacuation time t p1(j) . A rotary vane vacuum pump ( 10 ) designed for this purpose is characterized in that it has two inlets ( 1, 2 ) and one outlet ( 3 ), the two inlets ( 1, 2 ) being arranged offset at an angle to one another, and is also subject matter of the present invention, as is its use in the method according to the invention and a vacuum packaging machine which comprises a rotary vane vacuum pump ( 10 ) designed in this way.

1 . A method for evacuating at least two vacuum chambers i and j with a vacuum pump ( 10 ), comprising:
 a cylinder having an outlet, as well as a first inlet and a second inlet, whereby both inlets are connectable to said vacuum chambers i and j independently from each other, and   a rotor arranged eccentrically to a central axis of the cylinder and within the cylinder, said rotor forming a conveying chamber with an inner wall of the cylinder, and   at least two vanes, received in a movable way in respective slots of the rotor and, with rotation of the rotor, are pressed against the inner wall of the cylinder thereby forming sealing points thus dividing the conveying space into individual conveying chambers, in which gas can be conveyed from the first inlet to the second inlet and from the second inlet to the outlet of the vacuum pump, the second inlet being arranged offset by an angle to the first inlet in a conveying direction,   
       the method having the following steps:
 a) Providing the at least two vacuum chambers i and j with an initial pressure p 02(i)  and an initial pressure p 01(j) , where p 02(i) ≥p 01(j) ; 
 b) Connecting the second inlet to the vacuum chamber i and the first inlet to the vacuum chamber j; 
 c) Evacuating the vacuum chamber i from the initial pressure p 02(i)  to a final pressure p 12(i)  via the second inlet during an evacuation time t p2(i)  and simultaneously evacuating the vacuum chamber j via the first inlet from the initial pressure p 01(j)  to a final pressure p 11(j)  during an evacuation time t p1(j) ; 
 d) Closing and separating the vacuum chamber i from the second inlet and the vacuum chamber j from the first inlet. 
 
     
     
         2 . The method according to  claim 1 , whereby at least three vacuum chambers i, j and k are evacuated cyclically, which has the following steps:
 a) Providing said at least three vacuum chambers i, j, k with the initial pressures p 02(i) =p 02(k)  and p 01(j) , where p 02(i) >p 01(j) ;   b) Connecting the second inlet to the vacuum chamber i and the first inlet to the vacuum chamber j;   c) Evacuating the vacuum chamber i from the initial pressure p 02(i)  to a final pressure p 12(i)  via the second inlet during an evacuation time t p2(i)  and simultaneously evacuating the vacuum chamber j via the first inlet from the initial pressure p 01(j)  to a final pressure p 11(j)  during an evacuation time t p1(j) , whereby p 02(i) >p 12(i)  and p 01(j) >p 11(j) ;   d) Closing and separating the vacuum chamber i from the second inlet and the vacuum chamber j from the first inlet;   e) Connecting the second inlet to the vacuum chamber k and connecting the first inlet to the vacuum chamber i;   f) Evacuating the vacuum chamber k from the initial pressure p 02(k)  to a final pressure p 12(k)  via the second inlet during an evacuation time t p2(k)  and simultaneously evacuating the vacuum chamber i from the initial pressure p 01(i)  to a final pressure p 11(i)  during an evacuation time t p1(i) , whereby p 02(k) >p 12(k)  and p 01(i) >p 11(i) ;   g) Closing and separating the vacuum chamber k from the second inlet and the vacuum chamber i from the first inlet;   h) Optionally repeating steps b) to g).   
     
     
         3 . The method according to  claim 1 , wherein the final pressure p 12(i)  of the vacuum chamber i connected to the second inlet and the initial pressure p 01(j)  of the vacuum chamber j connected to the first inlet in step c) deviate from each other by a maximum of 25%. 
     
     
         4 . The method according to  claim 1 , whereby the initial pressure of the vacuum chamber j is p 02(j) =p 02 (i), whereby the initial pressures p 02(i)  and p 02(j) , in particular both, correspond to atmospheric pressure, comprising the following steps which are carried out before step a):
 a.i) Connecting the second inlet to the vacuum chamber j;   a.ii) Evacuating the vacuum chamber j from the initial pressure p 02(j)  to a final pressure p 12(j)  via the second inlet during an evacuation time t p2(j)  with p 12(j) =p 01(j) ;   a.iii) Closing and separating the vacuum chamber j from the second inlet.   
     
     
         5 . The method according to  claim 1 , wherein the evacuation times t p2(i/j)  via the second inlet and the evacuation times t p1(i/j)  via the first inlet differ from one another by a maximum of 30%. 
     
     
         6 . The method according to  claim 1 , wherein the vacuum chamber i and/or the vacuum chamber j is an external chamber which contains a package for a foodstuff. 
     
     
         7 . A vacuum pump, designed for carrying out the method according to  claim 1  comprising:
 a cylinder having an outlet, as well as a first inlet and a second inlet, both inlets being connectable to a vacuum chamber to be evacuated, and 
 a rotor arranged for rotation in a rotary vane chamber and having at least two vanes which project radially beyond a body of the rotor and define with an inner wall of the rotary vane chamber a conveying volume which, by rotation of the rotor, can be conveyed from the second inlet to the first inlet and from the first inlet to the outlet of the vacuum pump, 
 
       wherein the second inlet is arranged offset by an angle to the first inlet in a conveying direction. 
     
     
         8 . The vacuum pump according to  claim 7 , wherein the angle between the first inlet and the second inlet is designed according to the desired volume flows {dot over (V)} 1  und {dot over (V)} 2 . 
     
     
         9 . The vacuum pump according to  claim 7 , wherein the first inlet and/or the second inlet is a radial inlet. 
     
     
         10 . The vacuum pump according to  claim 7 , wherein the number of vanes is selected such that there is a sealing point between the first inlet and the second inlet. 
     
     
         11 . The vacuum pump according to  claim 7 , wherein the number of vanes is in the range of 3 to 17. 
     
     
         12 . A vacuum packaging machine comprising the vacuum pump according to  claim 7 . 
     
     
         13 . The method according to  claim 1 , wherein the final pressure p 12(i)  of the vacuum chamber i connected to the second inlet and the initial pressure p 01(j)  of the vacuum chamber j connected to the first inlet in step c) deviate from each other by a maximum of 5%. 
     
     
         14 . The method according to  claim 2 , wherein the final pressure p 12(k)  of the vacuum chamber k connected to the second inlet and the initial pressure p 01(j)  of the vacuum chamber j connected to the first inlet in step f) deviate from each other by a maximum of 25%. 
     
     
         15 . The method according to  claim 1 , wherein the evacuation times t p2(i/j)  via the second inlet and the evacuation times t p1(i/j)  via the first inlet differ from one another by a maximum of 5%. 
     
     
         16 . The method according to  claim 2 , wherein the evacuation times t p2(k)  via the second inlet and the evacuation times t p1(k)  via the first inlet differ from one another by a maximum of 30%. 
     
     
         17 . The method according to  claim 2 , wherein the vacuum chamber i and/or the vacuum chamber j and/or the vacuum chamber k is an external chamber which contains a package for a foodstuff. 
     
     
         18 . The method according to  claim 1 , said vacuum pump being a rotary vane vacuum pump. 
     
     
         19 . The method according to  claim 2 , said vacuum pump being a rotary vane vacuum pump. 
     
     
         20 . The vacuum pump according to  claim 7 , said vacuum pump being a rotary vane vacuum pump. 
     
     
         21 . The vacuum packaging machine according to  claim 12 , said vacuum packaging machine being a rotary vacuum packaging machine.