WO1989008196A1

WO1989008196A1 - Pressure alternator

Info

Publication number: WO1989008196A1
Application number: PCT/FI1989/000038
Authority: WO
Inventors: Viljo Juhana JÄRVENPÄÄ
Original assignee: Wiser Oy
Current assignee: Wiser Oy
Priority date: 1988-03-04
Filing date: 1989-03-03
Publication date: 1989-09-08
Anticipated expiration: 1990-09-04
Also published as: EP0362330A1; FI881011L; FI881011A0; FI881011A7

Abstract

The invention concerns a pressure alternator by means of which it is possible to generate both a desired negative pressure and a desired positive pressure, as required, in the same suction duct (2) without separate duct valves. The positive and negative pressures can be regulated readily. The pressure alternator has a construction of an ejector, and the positive pressure is obtained by closing the out-blow opening of the ejector by means of a separate spring/pressure-regulated (9) closing cover (8 and 8a). The same closing cover (8 and 8a) also operates as a safety valve and prevents access of positive pressure into the duct (2). The operation of the closing cover (8 and 8a) to close the medium flow that is being discharged out of the ejector may take place either as a component flow of the flow (3) produced by the ejector effect or as a separate flow controlled by the valve (4).

Description

Pressure alternator

The invention concerns a pressure alternator which comprises an ejector, provided with a feed, a suction duct, and with outlet openings, for the generation of negative pressure and in which said ejector the out-blow opening can be closed for the generation of positive pressure.

The invention relates to an ejector solution by means of which, when desired, suction or pressure can be produced for further use by the intermediate of a pipe connection. By means of the device in accord¬ ance with the invention, it is possible to produce pulsating states of negative pressure or positive pressure, e.g., in a closed space and, at the same time, to produce an adjustable positive pressure. A device in accordance with the invention is of use, and it is needed in particular in situations in which a material to be pumped is filled, i.e. sucked, into a pump or vessel by means of negative pressure and, alternatingly, pressed out by means of pressure.

It is known in prior art to produce the operations described above by means of solutions that comprise separate ducts for negative pressure and for positive pressure. This is why their construction is complicated and, consequently, also expensive and, moreover, the size of these prior-art solutions is remarkably large. Moreover, the use of two separate ducts is often a very difficult solution, because in such a case consideration must be given to properties and provisions related both to corrosion and to strength. The generation of negative pressure and positive pressure through the same opening requires at least a three-way valve of special construction, whose durability in operation under corroding conditions is difficult to achieve, which may prevent constant operation. If attempts are made to produce a situation of negative and positive pressure by means of other mechanically controlled methods, this requires the use of so- called back-stop valves, which causes leakages and requires special servicing in the long run. One prior-art solution for an equipment intended for the transfer of liquids is described in the FI Pat. Appl. 833313. In this prior-art equipment for the evacuation of air present in a container, an e ector pump is mounted in one opening of the container, the necessary negative pressure being produced by means of said ejector pump.

Moreover, in this prior- rt solution, the container can be subjected to pressure by closing the out-blow opening of the ejector, i.e. positive pressure is generated.

The object of the present invention is to provide a device that does not involve the drawbacks of the prior-art solutions. It is a partic¬ ular object of the invention to provide a device by whose means neg¬ ative pressure is generated and by whose means the negative pressure can be converted to a controlled, adjustable positive pressure.

In view of achieving the objectives stated above and those that will come out later, the device in accordance with the invention is mainly characterized in that at the outlet end of the ejector a cover is fitted, by means of which the out-blow opening can be closed by means of a tap at the ejector feed and of regulation of the cover, whereby it is possible to provide conversion of the negative pressure of the ejector to a controlled, adjustable positive pressure.

Further advantageous characteristic features of the device in accord- ance with the invention are disclosed in claims 2 to 6.

The device in accordance with the invention is based on an applied ejector suction, which is connected directly, by means of a connecting suction duct, to the space to be subjected to negative/positive pressure, without any special connections whatsoever, whereat the negative pressure is accomplished as normal ejector suction, and the positive pressure is accomplished by closing the out-blow opening of the ejector with a suitable closing force. The device in accordance with the invention corresponds to an ejector-eductor in whose suction opening positive pressure or negative pressure can be generated by to the out-blow opening of the ejector-eductor connecting a closing unit operating with an opening or adjustable force. The outlet opening can be opened by passing a component flow from the medium flow that generates the ejector suction to open the out-blow opening of the ejector.

In the following, the device in accordance with the invention will be described in detail with reference to an embodiment of the device in accordance with the invention illustrated in the attached figure.

In the embodiment of the device in accordance with the invention shown in the figure, compressed air is used as the medium in the ejector 1 through the feed 3. From the feed 3 there is a tap via a three-way valve 4. The ejector 1 produces a negative pressure in the suction duct 2 when the feed 3 is in operation and when the outlet end of the ejector 1 is open. The opening of the outlet end of the ejector 1 is produced thereby that pressure is passed through the valve 4 into the annular space 5a, which is a space closed by a seal ring 5 in the intermediate space formed by the tubular rings 11 and 12. The pressurized annular space 5a produces a displacement of the seal ring 5 by the permitted distance, whereby the closing member, which is pushed by the support arms 13 and pressed by a spring 9 from the other side, advantageously a cover 8, i.e. a closing cover

8 and its seal ring 8a, is detached from the end of the inner tubular ring 11 by the desired distance. Thereby the air discharged out of the ejector 1 can be discharged through the openings 6, which are placed between the support arms 13 and which are hereby uncovered, through the corresponding openings 7 in the outer tubular ring 12. In such a case the ejector 1 operates as a whole and produces a negative pressure in the suction duct 2.

When the three-way valve 4 is closed, the pressure in the annular space 5a can be discharged out of the space, being pushed by the adjustable spring 9. Thereby the cover 8 can be displaced so that the seal ring 8a of the cover 8 is pressed against the open end of the inner tubular ring 11 and closes the medium flow out of the ejector 11. The consequence is a positive pressure generated by the flow 3 in the suction duct 2, i.e. the negative pressure has been replaced by a positive pressure. The level of the positive pressure depends on the regulated force of the spring 9. Thus, by regulating the force of the spring 9 it is possible to adjust the positive pressure in the suction duct 2.

Thus, by means of the device in accordance with the invention, both negative pressure and positive pressure can be produced in the same suction duct 2 without altering the connections of the suction duct 2 in any way whatsoever. On the other hand, it should be noticed that the spring-loaded cover 8 is opened by means of an external annular seal 5, which can be considered as a so-called ring piston. The annular seal 5 does not reach contact with the medium 3 that flows in the ejector 1 or with the flow mixture that may possibly come out of the suction duct 2. By means of the regulating member 10 shown in the figure, the compression force of the spring 9 and, moreover, the distance of displacement of the cover 8 when the annular space 5a is pressurized can be regulated.

By means of the solution in accordance with the invention, as is described above, a simple and operative pressure variation device, i.e. a pressure alternator, is achieved. It is obvious for a person skilled in the art that a number of different alternative solutions can be developed from the embodiment of the device in accordance with the invention described above. For example, the spring 9 can be substituted for by an adjustable pressure cylinder, to which the cover 8 is connected, whereby the movement of the cover 8 can be carried into effect at the same time. Moreover, the out-blow opening of the ejector 1, the tubular ring 11, must be closed by means of the cover 8 and the seal rings 8a.

When the solution in accordance with the invention is used, problems caused by corrosion as well as possible blockings in the suction duct 2 or in its closing and opening means are avoided. The ejector device 1 in accordance with the invention and its components can be manufactured of corrosion-proof materials.

The feed 3 can be accomplished in the way described above, or also as completely separate via the three-way valve 4. As the valve 4, it is also possible to use a two-way valve if its outlet (flow quantity) exceeds the air quantity that comes into the component flow from the feed 3. By means of the component flow it is possible to regulate the desired positive pressure for the suction duct 2 differently from the spring force 9 by regulating the pressure and the amount of the component flow by means of the valve 4.

The closing cover 8 and the sealing ring 8a which produce the nega¬ tive/positive pressure can be detached, raised and/or pressed against the spring 9 also by means of a separate power unit, which said power unit, in such a case, replaces the annular cylinder 5 and 5a, but its function of operation continues to be to open/close the mixture of gas/medium discharged out of the ejector. At the same time, by means of the power unit, the positive pressure that is produced in the suction duct 2 is regulated.

The device in accordance with the invention includes a unit that regulates both negative pressure and positive pressure, whereby the device may also be used as a safety valve.

Above, the invention has been described with reference to some of its advantageous exemplifying embodiments only. This is, however, in no way supposed to confine the invention to these examples alone, but many variations are possible within the scope of the inventive idea defined in the following patent claims.

Claims

WHAT IS CLAIMED IS:

1. Pressure alternator which comprises an ejector (1), provided with a feed (3), a suction duct (2), and with outlet openings (6,7), for the generation of negative pressure and in which said ejector (l)-the out-blow opening (11) can be closed for the generation of positive pressure, c h a r a c t e r i z e d in that at the outlet end (11) of the ejector (1) a closing member (8) is fitted, by means of which the out-blow opening (11) can be closed by means of a tap at the ejec- tor (1) feed (3) and of regulation (9,10) of the closing member (8), whereby it is possible to provide conversion of the negative pressure of the ejector (1) to a controlled, adjustable positive pressure.

2. Pressure alternator as claimed in claim 1, c h a r a c t e r - i z e d in that the suction duct (2) of the ejector (1) can be connected directly to the vessel to be emptied and/or filled.

3. Pressure alternator as claimed in claim 1 or 2, c h a r a c ¬ t e r i z e d in that the closing of the out-blow opening (11) of the ejector (1) is provided by means of an annular cylinder operating by the intermediate of a tap of the feed (3) and consisting of a seal ring (5) fitted between tubular rings (11,12) and of support arms (13) attached to said seal ring.

4. Pressure alternator as claimed in any of the claims 1 to 3, c h a r a c t e r i z e d in that the closing member of the out- blow opening (11) of the ejector (1), favourably a cover (8), is fitted to form outlet openings (6) between the seal ring (8a) of the cover (8) and the support arms (13) .

5. Pressure alternator as claimed in any of the claims 1 to 4, c h a r a c t e r i z e d in that the regulation (9,10) of the cover (8) of the out-blow opening (11) of the ejector (1) is fitted to consist of a spring (9) and of regulation (10) of its loading.

6. Pressure alternator as claimed in any of the claims 1 to 5, c h a r a c t e r i z e d in that the pressure alternator can be used as a safety valve by setting the regulation (10) of the loading of the spring (9) at the desired level.