FI106975B - Regulation system for a pump and a method for regulating a pump - Google Patents

Description

106975 PUMP CONTROL SYSTEM AND METHOD FOR PUMP CONTROL

The present invention relates to a pump control system and a method for controlling the pump 5. In particular, the invention relates to a high-speed centrifugal pump used as a suction pump and its use in connection with various filtration materials.

One of the prior art is U.S. Patent No. 4,108,574, in which the disclosed solution has become known as a pump which determines two variables affecting the flow of the pump, for example power, rotational speed and / or differential pressure across the pump. When this information is combined with the measured flow rate data in a test run situation, the pump has a characteristic curve that no longer requires the pump flow rate to be measured in actual operation, but utilizes the two flow variables mentioned above, in this case pump power and rotational speed. Going a little further, the publication has made it possible to use the pump as a "consistency meter" for the pulp industry, for example, because consistency is one of the flow variables that can be determined from other flow variables on the basis of test runs. This publication explains the further processing of the information obtained from the pump in great detail and in many respects suitable for use in our present invention, naturally having in mind the objectives and starting points of our invention which are clearly different from the said US patent. For example, in paper machine technology, suction pump solutions have more than «· 4« heads based on technology that adjusts the vacuum generated by the pump to • · · · 25 empirically. This is a disadvantage.

US 4,329,201 deals with dewatering from a web on a wire. According to the publication, • · can be used for water mailing. keskipakoistyhjöpumppua. The idea described in the publication is characterized by seeking to use a constant vacuum for dewatering. Here. ···. 30 is achieved by the fact that dewatering equipment includes two drainage • • ·. ···. over which the wire passes. In the case of a new fabric, only one of the different • water is used. but, as the vacuum increases, another pipe is opened in the pipe and the suction of the suction device is also directed to the wire through the other pipe. According to the publication • ·. the solution also uses a control valve which, together with the vacuum control, maintains a constant vacuum pressure on the suction units «« • <I 1 · · • «•« 2 106975. The publication also mentions how the wire dwell time at each suction tube can be increased, if necessary, either by increasing the width of the suction slot in the suction tube in the direction of movement of the wire or by slowing the speed of the wire.

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In other words, the publication seeks to account for changes in the permeability of the wire during its lifetime, either by increasing the suction device, by changing their suction width, or by changing the suction time.

10 US 4,466,873 deals with dewatering of the flat wire section of a papermaking machine, as in the previous publication. The apparatus of this patent employs a variable speed vacuum pump, which may also be a centrifugal vacuum pump. The apparatus aims to control the dewatering in two cycles so that during the first cycle the pump rotation speed is set at a constant value, whereby the pump generates a sufficient vacuum for the drainage of the web. As the wire 15 gradually becomes clogged, the vacuum in the suction boxes increases. When the vacuum in the last suction box has increased to a predetermined value, the control unit orders the vacuum pump to reduce the rotational speed so that the vacuum still remains at the aforementioned mäc-simi value.

Although the solution of the publication takes into account the effects of wire clogging, it does not teach the supply of two resistance curves to the control unit, and of course their use so that the wire life can be optimized if desired.

I 4 4 («U.S. Patent 4,518,318 discloses control of electric motor and attached central fire pumps ··« «25 in various operating situations. Most of the publication refers to, for example, central heating system pumps whose operation, mainly rotational speed, is controlled with respect to radiators). The publication describes how the pump head has been supplied with a lift height - volume flow co-ordinate of both pump constant speed and so-called modulation curves. The MocLi-30 draw curve is a curve by which the lift height and volume flow are changed. when changing speed.

Ao. the problem addressed in the publication is power losses when the flow conditions in the network are changed. As a solution to this, the pump rotation speed P1479; Horo et al.

, 106975 from which according to flow conditions. The publication teaches in detail, starting from line 4 of column 4, how the pumping system is dimensioned for flow rate Qx and lift height Hx, thus corresponding to a situation where all thermostatic valves in the central heating piping are open. In partial load cases, where the valves are throttled or closed, the pump 5 should operate according to the curve Hr (Q). This is programmed in the pump control unit so that, for example, when several valves are closed, the pressure (= lifting height) in the pipeline increases and correspondingly the flow rate decreases if the pump rotation speed remains constant. In other words, in figure two, the constant speed curve is to the left. Switching points are provided to the Pim-Pun control system for each constant speed curve 10 so that, for example, as the system pressure rises to 57, the system drives the pump drive motor to reduce its speed. Similarly, the control system is able to control the pump to increase its speed if one or more valves are opened at the partial load position.

In other words, U.S. Patents 4,329,201 and 4,466,853 discussed above address issues related to paper web dewatering and wire change, but do not address them by utilizing pump characteristic diagrams. In the latter of these two publications, only the relationship between pump suction and rotational speed is known and exploited. US Patent 4,518,318 and DE 196 18 462, on the other hand, deal with the utilization of 20 characteristic diagrams, but in a different way and for a different purpose than in the following more detailed invention.

The new system according to the invention consists of a speed-controlled suction pump, an I I t • · ·: suction box and a measuring and control system.

e • · · 25 • · · • · 1; · 1 The system is characterized by the fact that, in operation, a pump characteristic diagram is stored in the central processing unit of the pump, which is used to calculate the flow of pumped * 1 1 pumping air from the measurement results. Based on the airflow and the measured vacuum level, · · · * · '1 calculates the total permeability of the tissue over the suction box or between the tissue and the web. This allows you to track changes in the density of • · - '···' over time as a function of the fabric or paper path, and to make any necessary changes in the process or condition of the fabric.

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• “1 automatically when lifting.

«· ♦« «« · · «· ♦>» »· • • • • • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·“ Horoetal.

4, 106975

A sufficiently large change in tissue permeability, possibly in combination with other, e.g., track and / or tissue moisture measurements, indicates the need for tissue replacement. In addition, trend tracking (lifetime tracking of tissue) allows you to compare different tissues, helping you find the best type of tissue.

Based on the measured data and the characteristic diagram of the new pump, the system is able to monitor the operating condition of the pump, for example, contamination, and may give an alarm.

According to the invention, a resistor function, or so-called resistor diagram, is stored in the memory of the pump central unit. The resistor function is stored in two different situations. A resistor function is stored in the machine's memory, which comprises an initial situation in which the felt fabric or filter material through which the medium is aspirated by the pump is new and non-clogged. According to the invention, a resistivity curve or resistor function which otherwise contains the same resistor components is also stored in the memory of the central unit, but now the material to be sucked in, such as tissue or filter material, is one which has been used and clogged. During operation of the pump, the operating point of the pum-20 pun is monitored (rotation speed, as achieved vacuum level at the pump suction side and achieved flow rate of pumped material, e.g. m3 / time unit). The pump is thus controlled so that its operating point remains within the permissible range (in the vacuum level-flow rate field) and the pump can also be controlled

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• "; such that the operating point is adjusted, for example, for the tissue

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25 rotation and / or control of pump speed and tissue obstruction * «»; · [Increase pump speed. However, it is essential that the pump operating point * * be kept within the allowable range determined by the pump resistor function f1 for new material, such as paper machine fabric and resistor function f2 for clogged and used material • · «* · * * , such as paper machine tissue. The operating point of the pump must be within the area delimited by the above-mentioned resistor functions.

According to the invention, the resistor functions f1, f2, f3 of the different felt types can be stored in the memory of the pump central unit 100 and the stored functions f1, f2 in the memory of the pump central unit. , f3 is always enabled when changing the felt type. These can • • • ·

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• · ·· P1479; Horo et al.

106975 and based on that trend tracking, the most appropriate felt for each paper / board mass can be selected.

The suction pump control system according to the invention and the method for adjusting the suction pump 5 are characterized by what is claimed.

The invention will now be described with reference to some preferred embodiments of the invention shown in the figures of the accompanying drawings, but which are not intended to be limited thereto.

10

Figure 1A shows the yield curve of a centrifugal vacuum pump. The horizontal coordinate system shows the flow rate / time unit and the negative pressure level achieved in the vertical coordinate system at the suction side of the pump. The graphs G1, G2, G3 are the torque curves and the graphs D1, D2, D3 are the rotation speed curves. At a given torque and at a certain speed 15, a certain flow rate and a certain vacuum level are achieved.

Figure 1B illustrates the determination of the pump output point. The functions f1, f2 represent resistance curves. The function f1 is the resistance curve for the new permeable material and f2 is the resistance curve for the old blocked material such as felt. D1, D2, 20 D3 are different speed curves. The figure illustrates the change in the yield point as the material ages. To achieve the same flow rate, the pump speed is increased. The change in the pump return point is plotted. E1. The graph in the horizontal coordinate shows the flow rate of the suction pump and the vertical I «<«,:. in the coordinate system the vacuum level at the suction side of the suction pump.

»· · · 25 • · • ·

Fig. 1C illustrates a suction pump according to the invention and associated control / measurement devices.

• · • · · t ·

Fig. 2A illustrates a system according to the invention in conjunction with a suction box of a papermaking machine. 30 tees.

··· • · · * · •. Figure 2B shows a resistor formed jointly by a wire and a pulp web, which is illustrated in Figs. the system of the invention is monitored.

«·« · «I« I I «I« • «I« «P1479; Horoet et al.

6 106975

Figure 2C shows a suction pump system according to the invention in connection with a filter material.

Figure 2D is a block diagram representation of operation in a pump system.

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Figure 1A shows the suction pump output curve. The suction pump 10 is preferably a centrifugal vacuum pump. The graph of Fig. 1A shows a so-called centrifugal vacuum pump 10. tur-bokompressor yield graphs. The figure shows the constant speed curves D1, D2, D3 ... that the constant torque curves G1, G2, G3 .... As shown in the figure, there is almost always a unique intersection point for a given torque and rotation speed. The output point (volume flow and vacuum level) of the pump 10 can then be determined by measuring the torque and rotational speed of the pump 10, i.e. its rotational speed.

In addition, by measuring the actual vacuum level, the output point can be checked to see if the pump 15 has changed in function, for example, due to wear or contamination.

By measuring the temperature and humidity of the medium to be sucked, the yield curves can be corrected because they affect yields in a known manner.

Figure 1B shows the determination of the output point of the pump 10. The vacuum pump 10 yield points are determined by the so-called. the system resistance curve f 1, f 2 ... together with the pump 10 rotation speed. The yield point settles on the resistance function of the speed graph. |. the so-called graph. and the intersection of the resistance curve.

i «t» · ♦ ·· 25 The shape of the resistance curve f1, f2 ... depends on how much air is absorbed by the suction system at different vacuum levels. The shape of the resistance curve, i.e. the flow resistance, is influenced by e.g. flow resistance of paper web φ and fabric, pipeline losses, valve positioning, etc. in the pipeline, etc.

·· .1. 30 For example, the resistance curve f1 of a new (clean and fluffy) blanket is a slightly rising ·· »curve. A slight increase in the vacuum level increases the volume flow considerably. The resistance curve f2 of the old blanket (clogged and • · · *. Compressed) is steeper, with a slight increase in the vacuum level. weather volume flow is low.

«« «« P1479; Horo et al.

«1 106975

As the felt ages, the centrifugal vacuum pump volume flow will be reduced if its speed is kept constant. If the flow rate is to be kept constant or increased, the rotational speed of the pump 10 must be increased. The pump's 10 output points can be adjusted during the life of the felt. Such adjustment can be carried out according to the invention on the basis of measuring doors (e.g., amount of water leaving the felt, moisture of the web).

The tissue resistance curve can be measured by varying the rotational speed of the pump and measuring its output point at different rotational speeds. The measurement can be made on a new tissue to determine its properties and compare with other tissues. By measuring the resistance curve of the old tissue, its condition and possible replacement need can be determined.

Fig. 1C shows the construction and instrumentation of the pump 10. The rotationally adjustable suction pump 10 is, for example, structured as a central centrifugal vacuum pump, the main parts of which are an engine 11, an impeller 13 mounted on a motor shaft 12, a spiral housing 14 and a bearing 15.

The rotational speed of the pump 10 is controlled by the frequency converter 16, from which it is possible to measure e.g. pump rotation speed and torque. The measurements of the pump 10 can be arranged, for example, as shown in the figure. The measurements marked on the picture are 20

Pl Suction vacuum pressure measurement

Tl Measurement of inlet air temperature

Ml Measurement of humidity in the intake air NO (S) Measurement of pump speed «25 NO (X) Measurement of pump torque • · · · · · · ·

Fig. 2A illustrates a pump system according to the invention, comprising a variable speed pump 10, preferably a suction pump and most preferably a central pump. 30 siphon vacuum pumps connected to suction duct 17, which suction duct is further connected to a water separator 18. Pump 10 sucks in vacuum into tank 18 into its internal space 19, •> and further supplies water / air to tank 18 via suction duct 20 suction 21, which is against tissue H1 of a paper machine / board machine.

• · • · • «•» »1 P1479; Horo et al.

«• · s 106975

Water from a fabric, such as felt H1 of a paper machine or board machine, is drawn into the interior space of the suction box 21 through the gaps between the slots 21 a1, 21a2 ... of the suction box 21. The water is further conveyed under reduced pressure to the water separator 18 in its internal space 19, from which the water can be discharged through the outlet conduit 18a. Suction box 21 can also be used to remove water M from the pulp web. In this case, the pulp web M is made of paper machine fabric, such as against wire H1, and dewatering takes place from the pulp web through wire H1 into the space inside the suction box 21 and further to the abovementioned water separator 18. The dewatering can be controlled

The system of Fig. 2A comprises the measuring sensors shown in the representation of Fig. 1C, by means of which the pump speed is further controlled by the measured data. The resistance curve f1 of the felt H1 of Fig. 2A, i.e. the resistance function when the felt is new and unused, is stored in the memory of the pump central unit 100. The resistance curve f1 is stored in the memory of the central unit 100 so that the pump is driven at different speeds 15 and the achieved vacuum under the pump inlet side between pump and felt for each speed and the vacuum pumped m3 / min associated with vacuum.

According to the invention, in addition, the resistance curve of the used blank H1, the vacuum level measured at different rotational speeds and the associated flow rate are stored in the memory of the central unit 100, respectively. The resistance function graph f2 thus represents the characteristic resistance curve of the felt H1 used.

f

When running a paper machine / carton machine, the pump rotation speed, or • • 25 rpm, and the vacuum and flow rate achieved with it are continuously measured. According to the invention, the rotation speed can be increased when the flow rate decreases or vice versa, whereby the pump is controlled by the central unit 100 on the basis of measurement data and, for example, when the felt becomes blocked, the central unit increases the pump rotation speed. so that the papermaking process itself does not- ···. 30 The disadvantages of blanket clogging. The quality of the paper remains good, as • the amount of water removal from the felt is kept constant, for example, throughout the papermaking process.

• · 1 P1479; Horoetal.

· · »106975

When measuring the resistance function of a new fabric of a paper machine / board machine such as felt H1 or wire, the resistance curve of that function can also be measured during pump operation, e.g., paper machine / board machine operation, where the resist function includes not only felt resistance but or the resistance caused by another felt. It is essential that when performing the comparison, the comparison should also be performed on a blocked blanket H1 which in its connection comprises corresponding resistance components, such as a pulp web, valves in certain control sections, piping etc. It is essential for the invention to monitor the paper machine fabric condition based on said monitoring and / or adjusting the speed of rotation of the pump 10 based on said monitoring.

Figure 2B illustrates a preferred embodiment of the invention. In the embodiment of Figure 2B, the resistor functions f1 and f2 are measured and recorded in the running condition of the paper machine / board machine 15, where the pulp track M is against the paper machine tissue H1.

Figure 2C shows a rotary adjustable pump 10 according to the invention in connection with filter material H100. The filter material may be, for example, a wire surface or perforated drum or disc of various scrubbers or precipitators. Other types of filters used in various industrial processes are also contemplated by the invention, such as vacuum filters for causticization of a pulp mill and e.g. in the fertilizer and base metals industries. The figure schematically illustrates a suction drum filter 30 whose filtrate compartments 32 located below a perforated or wire surface H100 are subjected to a suction suction.

···; pump 10. The procedure for controlling pump 10 is similar to that of Figures 2A and 2B

»·· ·· 1! 25 of the present invention.

2C, as shown in Figure 2C, the pump draws liquid through material H100, which is preferably · · · *; [· 1 filter material and the material to be filtered is located on one side of the filter material

• »I

in state F. Also in this embodiment, the resistance curve of the filter H100 can be measured during the use of the filter 30 first when the filter is new. The under pressure · · - 1 ;; · 1 pressure on the suction side of the pump and its associated flow rate and pump speed ··· 'depend on the H100 resistance curve and the corresponding data of the blocked filter ·' .1 ·. Also, in this embodiment, the pump, its speed, can be:: '': controlled by the operating point information obtained by measurements and when «« »* P1479; Horo et al.

10 106975 a certain unauthorized operating point is triggered, the CPU alarms this to stop the pump and replace the filter. The permissible operating range of the pump is between the resistance curve of the new material H100 and the resistance curve of the blocked material HIOO. The material absorbed by the pump may be air, gas, liquid. Thus, in the most general embodiment of the invention, the material absorbed by the pump is not limited to, for example, air.

Figure 2D illustrates the use of a pump system according to the invention. Block diagram of the step a) is measured and stored in the pump 10 at 1 to 10 in the memory unit 100 on the suction side of the pump 10 ominaisvastusfunktio f1 ie. resistance curve at different pump speeds during suction through new material introduced H1, H100. Thus, at a given speed, the achieved vacuum level at the suction side of the pump and the achieved flow rate corresponding to the vacuum level are recorded, for example, in m3 / min. In step b), the resistivity curve f2 of the blocked material H1, H100 is stored in the memory 15 of the central unit 100 of the pump 10. In step c), the CPU 100 microprocessor determines the operating ranges in general; the vacuum level and the corresponding flow rate at which the equipment is allowed to operate. In step d), the alarm limits are defined, i.e. the value ranges, i.e. the operating ranges, in which the system and the pump should not operate, whereby the alarm can be used to directly control the pump rotation speed and increase the rotation speed.

,;, The pump torque and the pump speed are measured while the pump is running, and the characteristic curve of the pump, J, pun is stored in the pump 10 and the data of these measured ··. ·. Based on these values, the pump 100 microprocessor directly calculates the flow rate associated with each torque • · and the vacuum level corresponding to the pump rpm and the associated vacuum level. From the intersection of the pump torque curves and rotation speeds it is possible to calculate • · · the vacuum level at the pump 10 operating points and the corresponding flow rate.

30 • ·, * ··, This allows you to compare the current operating point of the pump with the allowed operating points and to perform the alarm and / or pump control based on said operating point information and subsequent comparison.

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«· ♦ • · * P1479; Horo et al.

Claims (12)

A control system for a pump, which control system comprises a suction pump (10) with speed control and which system comprises a material (H1, H100) on the suction side of the pump, through which a medium, such as air or liquid, is sucked with the pump (10) and said system further comprising a sensor or equivalent which measures the rotational speed of the suction pump (10), characterized in that the central unit (100) of the pump (10) comprises a memory where the resistance function (f1) of the suction side of the pump is stored, whereby the suction resistance of the resistance function (f1) is formed. of at least the material connected to the suction side (H1, H100), whereby air or liquid is sucked, and that the memory of the central unit (100) stored the resistance function (f1) refers to an unused new material (H1, H100), and that the memory of the central unit (100) is also stored the second resistance function (f2) of the suction side of the pump, which function refers to a material used as a suction resistant material (H100, H1), the permeability of which t is changed during operation, and each resistive function (f1, f2) indicates the vacuum on the suction side of the pump reached at a determined rotational speed of the pump and the flow of medium (material volume / time unit) thus obtained through the material (H1, H100), is operated so that the operating location is within an allowable operating range which is limited to the resistance functions (f1 and f2) stored in the memory of the central unit ···: 25 (100). • · · • · · • · • ·: 1 Control system according to claim 1, characterized in that the material (H1), whereby the pump (10) sucks the medium, is a tissue at a paper · ··· • · · * · 1 1 / carton machine. 30 ··· '··· 1 Control system according to claim 1, characterized in that the material (H100), * 1 »··· 1 whereby the pump sucks the medium, is a filter material, such as, for example, a *: '': filter surface in a suction chamber or suction disc filter. ♦ 1 1 »· ♦ · * ··· * P1479; Horo et ai. · · »106975 Control system according to any of the preceding claims, characterized in that the pump (10) is connected to a vacuum chamber (18) or is further connected to a suction cup (21) or the like, where the tissue, such as a felt or wire, is against the paper machine. the suction box's surface area, and water is drawn through the strips (21 a1, 21 a2 ...) out of the wire 5 into the inner space of the suction tube (21) and further into the vacuum chamber (18), from which the water is withdrawn through an outlet (18a1). Control system according to any of the preceding claims, characterized in that in the process the resistance function of the suction side of the pump (the air volume and vacuum level associated therewith and the rotational speed of the pump associated therewith) is stored in the memory of the pump central unit which has a suction function as a suction function. the tissue at the paper machine, including the pulp web in conjunction with it, whereby the value pair is stored in the memory of the central unit during machine thread when the pulp web is in contact with the tissue of the paper machine. 15 Control system according to any of the preceding claims, characterized in that the resistance function of the suction side of the pump (10) is stored in the memory of the central unit (100) of the pump (10), which function relates to the filter material and the substance to be filtered, from which substance liquid or that air or gas is sucked through the filter material, the filter acting as an air filter or a gas filter. Method of operating a suction pump (10) with speed control, characterized in that a central unit (100) and a memory therein are arranged in conjunction with the <<· · · <·: the suction pump, in which memory the resistance function of the suction side of the pump can be stored. and that in the method the resistance function (f1) of the suction side of the pump (10) is stored in the memory of the central unit of the pump, in which function the resistance is formed by an unused new material '* (H1, H100), whereby air or liquid is sucked, and also a resistance function (f2) is stored as comparative data in the memory of the pump central unit in which function a material used (H1) , H100), whose permeability has changed, has been used as a suction resistor, through which material air or liquid is sucked, whereby in use it clogged ··· • · 1 · ··. * P1479; Horoetal. the material's data constitutes comparative data when controlling the pump's operation, when the pump's «« ··· 'operating location is within the operating range determined by •: ·: the graphic representatives of the resistance functions (f1 and f2). «.6 106975 Method according to claim 7, characterized in that the material (H1), whereby the medium is sucked, is constituted by a tissue at a paper / cardboard machine, such as a blanket or a wire. 5 Method according to any of the preceding claims, characterized in that the material (H100), whereby liquid or air is sucked, is constituted by a filter material, the resistive function relating to the material in question, ie. vacuum level on the suction side of the pump which has been reached with a determined rotational speed of the pump and the flow volume (m3 / min) associated with it, is stored in the memory of the central unit of the pump (10). Method according to any of the preceding claims, characterized in that the speed of rotation of the pump is controlled within the range of operation between the graphic representatives of the resistance functions (f1 and f2). 15 Method according to any of the preceding claims, characterized in that the suction side of the pump is connected to a vacuum chamber, which vacuum chamber is further joined to a suction cup or the like, through which moldings the tissue of the paper machine, such as a felt or wire, is arranged to run, and the method comprises measuring the vacuum level on the suction side of the pump, the speed of rotation of the pump and the temperature of the medium sucked with the pump. Method according to any of the preceding claims, characterized in that the "·· resistance functions of several different tissues of the paper machine (vacuum - • · ···! Flow volume) are stored by the method in the memory of the pump unit (10) and it is selected. 1, upon insertion of the pump (10), out of the stored functions, the specific «: 'tissue-type resistance function which is current in the present use of the paper machine, · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · the pump operating point is compared when operated with the resistance function (f2) of the · · · * · 1 1 used tissue, whose permeability has changed, which function serves as an alarm limit. • »• 1 '···' P1479; Horoetal. · • · • · ·