DD118144B1

DD118144B1 - METHOD AND DEVICE FOR FAST EVACUATION OF SMALL BOXES

Info

Publication number: DD118144B1
Application number: DD18587975A
Authority: DD
Inventors: Lothar Reissmueller; Dietrich Huebner
Original assignee: Lothar Reissmueller; Dietrich Huebner
Priority date: 1975-05-07
Filing date: 1975-05-07
Publication date: 1988-11-30
Also published as: DD118144A1

Description

Dazu wird eine Einrichtung verwendet, bei der der zu evakuierende Behälter über zwei Ventile mit einer Evakuierungseinrichtung, die zwei Expansionsvolumina und mindestens eine mechanische Vorvakuumpumpe aufweist, verbunden ist, wobei durch eine mit bekannten Mitteln vorgenommene Zeitsteuerung der Ventile der Einrichtung die Durchführung des Verfahrens realisiert wird.For this purpose, a device is used, in which the container to be evacuated via two valves with an evacuation device having two expansion volumes and at least one mechanical backing pump is connected, which is carried out by a time-controlled by known means timing of the valves of the device, the implementation of the method ,

embodiments

Die Erfindung soll nachstehend an mehreren Ausführungsbeispielen näher erklärt werdenThe invention will be explained in more detail below on several embodiments

In der zugehörigen Zeichnung zeigen: In the accompanying drawing show:

Fig. 1: Schema der EvakuierungseinrichtungFig. 1: Scheme of the evacuation device

Fig. 2: Schema der Evakuierungseinrichtung mit einer zweistufigen VorvakuumpumpeFig. 2: Scheme of the evacuation device with a two-stage backing pump

Gemäß Fig. 1 ist der zu evakuierende Behälter 1 über ein Ventil 2 und eine Leitung 4 mit einer mechanischen Vorpumpe 6, sowie über ein Ventil 3 und die Leitung 5 mit einer mechanischen Vorpumpe 7 verbunden. Die Evakuierung von 1 geschieht nun in der Weise, daß zunächst das Ventil 2 geöffnet wird. Es findet Druckausgleich mit der Leitung 4, der Pumpe 6 und dem angebrachten zusätzlichen Volumen 8 statt, der sehr schnell geht und bis zu einem Druck von 1 bis 10 Torr führt.According to FIG. 1, the container 1 to be evacuated is connected via a valve 2 and a line 4 to a mechanical roughing pump 6, as well as via a valve 3 and the line 5 to a mechanical backing pump 7. The evacuation of 1 is now done in such a way that first the valve 2 is opened. There is pressure equalization with the line 4, the pump 6 and the attached additional volume 8 instead, which goes very fast and leads to a pressure of 1 to 10 Torr.

Danach wird Ventil 2 geschlossen und kurzzeitig Ventil 3 geöffnet. Hier expandiert das restliche in dem Behälter 1 verbliebeneThereafter, valve 2 is closed and valve 3 is opened for a short time. Here, the remaining remaining in the container 1 expands

Gas in die Leitung 5, die Pumpe 7 und den Behälter 9, der so dimensioniert ist, daß durch diese Expansion der gewünschte Druck im Behälter 1 erreicht wird.Gas in the line 5, the pump 7 and the container 9, which is dimensioned so that the desired pressure in the container 1 is achieved by this expansion.

Ventil3 wird wieder geschlossen. In der Zeit bis zur nächsten Evakuierung werden die Evakuierungszweige durch die Vorpumpen wieder auf einen niedrigen Druck evakuiert.Valve3 is closed again. In the time until the next evacuation evacuation branches are evacuated by the forepumps back to a low pressure.

Bei günstiger Gestaltung der beiden Evakuierungszweige können die Pumpen 6 und 7 die erste und die zweite Stufe einerWith a favorable design of the two Evakuierungszweige the pumps 6 and 7, the first and the second stage of a

zweistufigen Vorvakuumpumpe (beispielsweise Drehschieberpumpe) 7 (Figur 2) sein.two-stage backing pump (for example, rotary vane pump) 7 (Figure 2).

Claims

1. A method for repeated rapid evacuation of small containers with a volume less than 0.11 or a plurality of such containers successively from normal pressure to a pressure of liquid nitrogen not ausfrierbaren gases between 5 · 10 ~ ¹ Torr and 1 · 1 (T ³ Torr in a time less than or substantially less than 1 s, characterized in that with the aid of at least two controlled in a known manner valves according to a time program initially 90 to 99.9% of the gas from the container to be evacuated in a first Evakuierungszweig and then the remaining 10th expand to 0.1% to the desired final pressure in a second evacuation branch, wherein the pumping out of the gas from the first evacuation branch at a pressure above the final pressure and from the second Evakuiecungszweig at a pressure below the final pressure of the container to be evacuated mainly in the after Termination of expansion and shut-off of the container until the next evacuation g takes place.

2. Device for carrying out the method according to claim 1, characterized in that the container to be evacuated (1) via a valve (2) and a line (4) with a mechanical backing pump (6) and via a valve (3) and the Line (5) connected to a mechanical backing pump (7) and to the line (4) an auxiliary volume container (8) and to the line (5) an auxiliary volume container (9) is connected.

3. Device according to claim 2, characterized in that the pumps (6) and (7) are replaced by a two-stage backing pump (7), wherein the conduit (5) at the second stage and the conduit (4) between the first and second stage is connected.

For this 1 page drawings

The invention relates to a method and a device for repeated rapid evacuation of small containers, wherein after the rapid evacuation of the container, the entire time until the next evacuation is used for pumping out the gas from the evacuation device.

Characteristic of the known state of the art

It is known to evacuate containers to a predetermined pressure with a mechanical backing pump, e.g. As a rotary vane pump to perform a valve and a pipe. After opening the valve, the gas (usually air) flows from the tank into the pipe and the pump until pressure equalization. The pump then delivers this gas from the total volume until the desired pressure is reached.

Significantly shorter times can be achieved if an additional container with such a large internal volume is installed in the line, that already the pressure equalization with the small container to be evacuated leads to the desired pressure. The former method has the disadvantage that the pressure decrease per unit time with decreasing pressure is always lower because the guide values of Abpumpweges and the suction power of the pump with the pressure are smaller. If the total volume is a multiple of the container volume, the time required for the evacuation will be many times that calculated from the volume of the container and the pumping speed. After pumping off the container, the connected pump works useless against the shut-off valve until further evacuation. In the second method, the total amount of gas must be pumped out at a pressure that is less than the desired pressure. As a result, an inappropriately large pump must be used. In addition, the cost of the considerable volume of the additional container is significant.

Object of the invention

It is the purpose of the invention to develop a method and a device with which it becomes possible to repeatedly evacuate one or more containers within a short time. The invention is based on the object, one or more containers with a volume less than 0.1 liter in a time less than 1 s from atmospheric pressure to in the range of 5 · 10 ~ ¹ to 1 · 1S ³ Torr without expensive auxiliary equipment with small mechanical backing pump to evacuate.

Explanation of the essence of the invention

According to the invention the object is achieved in that the removal of 90 to 99.9% of the gas from the container by an expansion into a volume of the evacuation takes place, in which case the gas from this volume at a higher than the final desired in the system pressure is pumped in the time until the next evacuation of the container and then the remainder expands into a volume of the evacuation device, which is also used to evacuate this volume, the time until the next evacuation of the container.