DE102010043168A1 - Method for filling pressure reservoir with e.g. oil, in fluid system of fibrous material web manufacturing machine e.g. paper manufacturing machine, involves controlling moving velocity of piston by selection of pressure chambers - Google Patents

Abstract

The method involves connecting multiple pressure chambers (11-14) with a pressure reservoir (4) by a digital steered pressure regulator (3) during movement of a piston (10) against a load to convey fluid from the pressure chambers to the pressure reservoir. Moving velocity of the piston is controlled by appropriate selection of the pressure chambers to be connected with the pressure reservoir such that pressure-effective total effective area is smaller than total effective area during a preceding movement of the piston against the load with pressure.

Description

The invention relates to a pressure accumulator filling method for a fluid system, and more particularly relates to an accumulator filling method for a fluid system of a machine for producing a fibrous web, such as a paper, board or tissue machine.

In paper machines, working fluid (for example hydraulic oil, air, water, different gases or emulsions or mixtures of these fluids) is widely used as actuation and control means; In particular, actuators are hydraulically driven, with which large forces can be set and exercised with high accuracy.

In general, a working fluid is used, which is pressurized by a pump and stored in a pressure accumulator. The introduction of the pressurized working fluid into a fluid operated actuator, such as a fluid cylinder or fluid motor, is more recently controlled by digitally controlled valves that form a pressure regulator.

The operation of a digital pressure regulator is for example in the magazine "Fluid", No. 7-8, 2008, pages 12-13 is described in more detail and is briefly summarized below:
A digitally controlled pressure regulator consists in the simple case of a series of parallel-connected, digitally controlled valves, which have only an open / close function, and in the idle state (close-to-off state) are sealed. So there are simple on-off switching valves that allow or interrupt a flow and can be consistently referred to as valves in this application. The valves themselves may be conventional solenoid valves, ie valves with electromagnetic drive. Of course, other forms of drive can be chosen.

By opening and closing individual valves or valve combinations, which are determined and selected on the basis of mathematical models by a computer, a very rapid and precise pressure adjustment in the output line or in the actuator connected thereto can now be achieved. This is achieved by replacing the analogue control curve of a conventional proportional control valve with a digitally generated (approximate) control curve. Due to the omission of non-linearities and / or hysteresis of the analogue proportional valve, this curve can be a step-like approximated straight line which allows a control point to approach a control point quickly and (virtually) free of overshoot. A use of such pressure regulators is for example in the WO 2009/077650 A1 described.

An advantage of using a digitally controlled pressure regulator is that the digitally controlled valves are either open or closed; d. H. to maintain a desired pressure in a closed (and unchanged) system, the valves are only closed and there are no internal leakage currents. This is a significant difference from the conventional proportional valve, which is always traversed by a fluid flow. This constantly costs energy for the fluid pumps, for example in the paper machine.

Thus, it can be seen that the use of a digitally controlled pressure regulator allows energy to be saved.

However, there is still a need to further reduce the energy consumption in a fluid system, in particular from a machine for producing a fibrous web.

This object is achieved with a Druckspeicherfüllverfahren with the features of the independent claims.

Advantageous developments of the invention are the subject of the dependent claims.

The accumulator filling method according to a first aspect of the present invention is an accumulator filling method for a fluid system, in particular a fibrous web making machine, comprising a digitally controlled pressure regulator comprising at least one digitally controlled on / off valve which is sealed at rest the pressure regulator connected pressure accumulator, and at least one fluid pressure driven piston-cylinder device whose piston, acts on a load, a plurality of active surfaces for moving the piston against the load, each associated with a pressure regulator connected and separately switchable pressure chamber. The process has the following step:
Connecting, following a movement of the piston of the load, one or more of the pressure chambers by means of the pressure regulator with the pressure accumulator to promote fluid from the pressure chambers to the pressure accumulator,
wherein the pressure chambers to be connected are selected so that the pressure-effective total effective area is smaller than that in a preceding movement of the piston against the load with pressure applied total effective area.

With this method, it is possible to use a portion of the fluid that is in the previous movement of the piston against the load in the pressure chambers has been promoted, following a movement of the piston of the load following from the pressure chambers to promote the pressure accumulator; that is, a portion of the energy consumed to move the piston against the load is recovered (and fluid is not simply discharged, for example, into a fluid tank).

A movement speed of the piston following a movement of the piston of the load is preferably controlled by suitable selection of the pressure chambers to be connected (and thus the pressure-effective surface). If the pressure regulator is formed of several digitally controlled open / close valves, which preferably have different flow rates (for example, in a 1: 2: 4: 8 ... series ratio, depending on the number of valves), there is an additional or alternative possibility to control the movement speed of the piston following its movement of the load is to open suitably selected open / close valves, i. H. Valves with suitable flow rates, so that there is a desired total flow rate and thus a desired speed of movement of the piston.

Preferably, the piston-cylinder device is designed double-acting, in such a way that the piston one or more active surfaces, which is associated with each of which one connected to the pressure regulator and separately switchable back pressure chamber, for the load following movement or having.

It is preferred in such a construction, following a movement of the piston of the load following, fluid from the chamber or chambers, which is not connected to the pressure accumulator /, to the back pressure chamber or the back pressure chambers tracked. Alternatively or additionally, it is also possible to track fluid from the accumulator to the back pressure chamber or the back pressure chambers.

Preferably, the accumulator is a high pressure accumulator and the fluid system further includes a low pressure accumulator connected to the pressure regulator. That is, according to this embodiment, upon movement of the piston following the load, fluid is returned from the pressure chambers to the high-pressure accumulator. This achieves a particularly high degree of recovery, and the recovered fluid in the high-pressure accumulator can be reused or reused for a large number of applications.

In this embodiment, it is preferred, following a movement of the piston of the load, fluid from the low pressure accumulator to a chamber or chambers for the load following movement of the piston tracked.

Preferably, in the two embodiments described above, the total effective area pressurized with the preceding movement of the piston against the load is acted upon by pressure from the low-pressure accumulator. That is, for the method of the piston against the load fluid from the low-pressure accumulator is used, while in a method of the piston of the load following a part of the supplied fluid is conveyed from the pressure chambers in the high-pressure accumulator. This ensures a particularly favorable energy balance.

Preferably, the accumulator filling method is a method for a fluid system in which the load on the piston is the weight of a roller, particularly a machine for making a fibrous web, and the piston is moved following the load to open a nip, and / or the piston is moved against the load to close a nip.

A second aspect of the invention relates to a pressure accumulator filling method for a fluid system, in particular a machine for making a fibrous web, comprising a digitally controlled pressure regulator comprising at least one digitally controlled on / off valve which is sealed at rest and connected to the pressure regulator Accumulator, a fluid pump for pressurizing and conveying fluid to the accumulator, and a fluid-operated device, preferably in the form of a fluid tube for actuating a doctor blade, wherein the fluid-operated device is actuated by withdrawn from the pressure accumulator fluid whose pressure is adjusted by means of the pressure regulator , In this case, the Druckspeicherfüllverfahren the step of intermittently operating the fluid pump in order to replenish a pressure accumulator removed by actuation of the fluid-operated device amount of fluid.

By employing digitally controlled open / close valves in the fluid system which are sealed at rest, pressure of the fluid operated device can be maintained without the need to continuously remove pressure from the accumulator. Furthermore, considerable energy savings are possible throughout the system by only intermittently operating the fluid pump.

Another advantage of the above embodiment is that it is sufficient to use a very small fluid pump or a fluid pump with low power. Preferably, the fluid pump is an electrically operated pump, such as a mini or Micropump (eg a diaphragm pump). The fluid pump can also be manually operated.

Preferably, the fluid system to which the accumulator filling method according to the second aspect is applied has a plurality of fluid-operated devices, and each of the fluid-operated devices has its own accumulator and its own fluid pump. This allows a functional and spatial breakdown of the pressure supply can be achieved, d. H. individual local pumping stations and accumulators are provided, which are independent of each other, so that long strands of wire omitted.

This brings particular advantages in a fibrous web machine (eg in a paper machine) in which the expense for the provision, installation and maintenance of pipelines for the supply of fluid-operated devices is considerable. Because the materials used must be corrosion-resistant for the moist hot environment, there are enormous distances to cope with, because a conventional paper machine is simply large (several tens of meters long), so that here the material consumption of high-quality raw material is a real cost factor. In addition, there are flow losses in the management of fluid flows in the lines, either by larger pipe cross-sections, d. H. more material consumption, or by higher pumping power, d. H. higher energy consumption, must be balanced.

Preferably, according to the accumulator charging method of the first and second aspects, a fluid used in the fluid system is oil, water, gas or a mixture thereof (for example, water-oil, water-gas, two intermixed gases, etc.).

The invention will be explained below with reference to various aspects by means of exemplary embodiments with reference to the accompanying drawings.

1 schematically shows a fluid system to which the accumulator filling method according to the first aspect of the invention is applied.

2 schematically shows a fluid system to which the accumulator filling method according to the second aspect of the invention is applied.

This in 1 The fluid system shown is a fluid system of a paper machine and has a fluid-driven piston-cylinder device 1 with a piston 10 and four associated pressure chambers 11 . 12 . 13 . 14 , a variety of digitally controlled switching valves 2 for selectively connecting the pressure chambers to a high-pressure line HP or a low-pressure line LP, and a pressure regulator connected to the high-pressure line HP and the low-pressure line LP 3 consisting of a plurality of parallel and digitally controlled valves to a pressure in the pressure chambers of the piston-cylinder device 1 set individually. The system further includes a high pressure accumulator 4 that's about the pressure regulator 3 is connected to the high pressure line HP, and connected to the low pressure line LP low pressure accumulator 5 , Further, a fluid pump 6 for pressurizing and conveying Fuid from a tank 7 to the high-pressure accumulator 4 and a drain valve 8th for draining fluid from the low-pressure line or via the pressure regulator 3 from the high pressure line into the tank 7 intended.

In this system acts on the piston 10 the load of a roller in the paper machine, in the direction down in 1 , Therefore, the pressure chambers 11 and 12 or the corresponding to these pressure chambers active surfaces of the piston 10 Pressure chambers or active surfaces for moving the piston 10 against the load. The pressure chambers 13 and 14 are separate switchable back pressure chambers for the load following movement of the piston 10 , It should be noted that the piston-cylinder device 1 can be configured arbitrarily and, for example, may be formed from a plurality of pistons, as long as it has a plurality of active surfaces for moving the piston / piston against the load, which is associated with a separately switchable pressure chamber. (A detailed example of a structure and a control of a piston-cylinder device by means of a digital pressure regulator is, for example, in the German Patent Application No. 10 2010 001 337.4 described).

According to one possible embodiment of the accumulator filling method according to the first aspect of the invention, the pressure chambers become 11 and 12 via the corresponding switching valves 2 connected to the low pressure line LP, so that the piston 10 moved against the load, for example, to close a nip in the paper machine. If the nip is then reopened, one of the pressure chambers becomes 11 . 12 , which were previously used to move the piston against the load, via the switching valves 2 and the pressure regulator 3 with the high-pressure accumulator 4 connected. That is, a pressure-effective total effective area of the piston corresponding to the pressure chamber communicating with the high pressure accumulator (ie, the one to the pressure chambers 11 or 12 associated pressure-effective effective area of the piston) is compared to the total effective area (the two pressure chambers 11 and 12 associated pressure-effective effective areas of the piston), which in the previous movement of the piston has been acted upon against the load with pressure from the low pressure line.

In other words, to close the nip, a large pressure-effective total effective area of the piston is selected, whereby the nip can be closed with a low pressure, ie the piston can be moved with a low pressure against the load. On the other hand, in order to open the nip, a small pressure-effective total effective area is selected, which, in conjunction with the load acting on the roll, creates a pressure which is higher than the pressure in the high-pressure accumulator 4 is so that fluid from the high-pressure accumulator 4 connected pressure chamber to the high-pressure accumulator 4 can be promoted.

The speed of the piston following its movement of the load can be determined by appropriate selection of the pressure chambers 11 or 12 done with the high-pressure accumulator 4 is connected, ie to the pressure chambers 11 . 12 associated pressure-sensitive surfaces, which are different in this example.

The digitally controlled valves that control the pressure 3 In this example, they have different flow rates, which are in a fixed relationship to each other, in this example 1: 2: 4: 8: 16, so that the speed of movement of the piston 10 alternatively or additionally can be controlled by selecting appropriate valves; that is, the valve or valve combination that sets the flow rate that matches the desired velocity of movement of the piston is selected 10 leads.

Furthermore, it is possible in this system, during a movement of the piston 10 Following the load, fluid from the chamber 11 . 12 not with the accumulator 4 is connected via the switching valves 2 to one or both back pressure chambers 13 . 14 to track. Alternatively or additionally, it is possible in this case, fluid from the low-pressure accumulator 5 to the back pressure chambers 13 . 14 nachzuführen or, in particular, if the low-pressure accumulator 5 empties, fluid from the high-pressure accumulator 4 over the pressure regulator 3 and the low pressure line LP to the back pressure chambers 13 . 14 to track. The last two options are in the 1 indicated by bold arrows. It is also possible to pressureless fluid from the tank 7 to the back pressure chambers 13 and 14 to track.

The fluid used in this example is hydraulic oil; but it can also be used any other fluid.

In 2 For example, an example of a fluid system of a paper machine to which the accumulator filling method according to the second aspect of the invention is applied is shown. The fluid system has a fluid tube 1 Example of a fluid-operated device for actuating a doctor blade in the paper machine, a pressure regulator 2 , which in this example consists of two digitally controlled on / off valves, which are at rest, a pressure accumulator 3 that's about the pressure regulator 2 with the fluid hose 1 connected, and an electrically operated mini-pump 4 on, which pressurizes fluid and to the accumulator 3 promotes. Furthermore, there is a pressure sensor 5 for detecting the pressure in the fluid tube 1 intended.

To increase the pressure in the fluid hose 1 Will that be with the accumulator 3 connected valve of the pressure regulator 2 opened, allowing pressure from the accumulator 3 in the fluid hose 1 flows. To reduce the pressure, the other valve of the pressure regulator 2 opened, which derives the pressure. Since the valves are sealed at rest, a pressure remains when the pressure regulator is not actuated 2 in the fluid tube 1 almost constant. Therefore, a promotion of fluid from the accumulator 3 only in the case of a desired pressure increase in the fluid hose 1 required. This in turn makes a refilling of the accumulator 3 taken fluid quantity only at the time of removal or after removal of a certain amount of fluid necessary. The minipump is therefore operated only when fluid is removed from the accumulator or after the amount of fluid in the accumulator, for example, due to a plurality of time-spaced withdrawals, has fallen below a predetermined amount of fluid. If the system is used in common paper machines, this is often only a few times a day or a week. Therefore, the pump can be made very small, which is favorable in terms of energy consumption. Alternatively, it is also possible to use a hand-operated pump instead of the electrically operated minipump.

In a paper machine are generally a plurality of such fluid hoses 1 intended to operate associated doctor blades. With regard to lines to be saved, it is particularly advantageous in such a system if each fluid hose 1 with its own accumulator 3 and a private mini pump 4 Is provided. As a result, the line overhead is considerably reduced, in contrast to a central supply.

For example, if six meters of wire per blade were saved, the savings would be significant in terms of power supply; in the range of 50 to 200 euros per installed meter. These savings are especially there possible where the pressure regulator can be positioned with the pump in the immediate vicinity of the fluid tube (taking into account the ambient temperature and ambient climate in the engine room).

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2009/077650 A1 [0005]
• DE 102010001337 [0030]

Cited non-patent literature

• "Fluid", No. 7-8, 2008, pages 12-13 [0004]

Claims (12)

Druckspeicherfüllverfahren for a fluid system, in particular of a machine for producing a fibrous web, with a digitally controlled pressure regulator comprising at least one digitally controlled on / off valve, which is sealed at rest, a pressure accumulator connected to the pressure regulator, and at least one fluid pressure-driven piston-cylinder device whose piston, on which a load acts, has a plurality of active surfaces for moving the piston against the load, to each of which a pressure chamber connected to the pressure regulator and separately switchable pressure chamber is assigned, the method comprising the following step: Connecting, following a movement of the piston of the load, one or more of the pressure chambers by means of the pressure regulator with the pressure accumulator to promote fluid from the pressure chambers to the pressure accumulator, wherein the pressure chambers to be connected are selected so that the pressure-effective total effective area is smaller than that in a preceding movement of the piston against the load with pressure applied total effective area. Druckspeicherfüllverfahren according to claim 1, characterized in that a movement speed of the piston is controlled following its movement of the load by appropriate selection of the pressure chambers to be connected, and / or the pressure regulator has a plurality of digitally controlled open / close valves, preferably with different flow rates, and the speed of movement of the piston is controlled by opening suitably selected open / close valves. Druckspeicherfüllverfahren according to claim 1 or 2, characterized in that the piston-cylinder device is configured double-acting, such that the piston one or more active surfaces, each of which is associated with the pressure regulator connected and separately switchable back pressure chamber, for the Load following movement or having. Druckspeicherfüllverfahren according to claim 3, characterized in that, following a movement of the piston of the load, fluid from the chamber or chambers, which is not connected to the pressure accumulator /, and / or fluid from the pressure accumulator via the pressure regulator to the / the counter-pressure chamber (s) is tracked. Druckspeicherfüllverfahren according to one of claims 1 to 4, characterized in that the pressure accumulator is a high pressure accumulator and the fluid system further comprises a low pressure accumulator connected to the pressure regulator. Druckspeicherfüllverfahren according to claim 5, characterized in that, following a movement of the piston of the load, fluid from the low pressure accumulator to a chamber or chambers for the load following movement of the piston is tracked. Druckspeicherfüllverfahren according to claim 5 or 6, characterized in that the in the previous movement of the piston against the load pressurized total effective area is acted upon by pressure from the low-pressure accumulator. Druckspeicherfüllverfahren according to one of claims 1 to 7, characterized in that the load acting on the piston is the weight of a roller, in particular of a machine for producing a fibrous web, and the piston is moved following the load to open a nip, and / or the piston is moved against the load to close a nip. Druckspeicherfüllverfahren for a fluid system, in particular of a machine for producing a fibrous web, with a digitally controlled pressure regulator comprising at least one digitally controlled on / off valve, which is sealed at rest, a pressure accumulator connected to the pressure regulator, a fluid pump for pressurizing and delivering fluid to the accumulator, and a fluid-operated device, preferably in the form of a fluid tube for actuating a doctor blade, which is actuated by fluid withdrawn from the pressure reservoir, the pressure of which is adjusted by means of the pressure regulator, the method comprising the following step: Intermittently operating the fluid pump to replenish an amount of fluid withdrawn from the accumulator by actuation of the fluid-actuated device. Druckspeicherfüllverfahren according to claim 9, characterized in that the fluid pump is electrically operated or manually operated. Pressure accumulator filling method according to claim 9 or 10, characterized in that the fluid system comprises a plurality of fluid operated devices, and Each of the fluid-operated devices is assigned its own pressure accumulator and its own fluid pump. An accumulator filling method according to any one of claims 1 to 11, characterized in that a fluid used in the fluid system is oil, water, gas or a mixture thereof.

Images