DE202013101969U1 - Press for the production of biomass material panels - Google Patents

Abstract

Press for the production of biomass material panels, comprising the following components:
- At least one heating plate (4), which has heating channels (5) for passing thermal oil;
A secondary pump (20) in the secondary circuit (19) for conveying thermal oil to the heating channels (5),
- At least one measuring device (7, 8) for measuring the flow temperature (T _V ) and the return temperature (T _R );
- means for forming the value of the differential temperature (ΔT) from flow temperature (T _V ) and return temperature (T _R );
- A control unit (14) for controlling the rotational speed of the secondary pump (20) in dependence on the differential temperature (.DELTA.T) as a reference variable.

Description

The invention relates to a press for producing material plates from biomass according to the preamble of claim 51

In the production of material plates, a starting mixture of biomass such as chips, fibers and / or chips of wood, optionally with the addition of binder and / or plastic, is used, which is scattered by means of a scattering station to a pressed material mat and in a press using Pressure and heat is pressed into a material plate and cured. Of particular importance for the quality of the material plate is the heating plate temperature T _H , which should be kept almost constant in the press. The heating plates are brought to the heating plate temperature T _H by means of a circulating fluid flow which flows through the heating plates, wherein a thermal oil or another suitable heat transport medium can be used as the fluid. The thermal oil is thereby provided with a starting temperature T _P of a primary circuit and fed by means of a secondary pump in a secondary circuit via a control valve of the heating plate.

From the DE 10 2004 019 429 A1 It is already known that, in addition to the heating plate temperature T _H , the flow temperature T _V at which the thermal oil enters the heating plate is also measured. The flow temperature T _V , which is always well below the starting temperature T _P , is usually dependent on many parameters, but also basically due to the material to be pressed, the binder used, the press thickness, the heating plate and its thickness and the type of press. In one possible example for the production of a chipboard, a value of 290 ° C. results for the starting temperature T _P and a value of 260 ° C. for the flow temperature T _V.

The heat flowing through the plates thermal oil is extracted during the pressing process heat, so that the thermal oil after leaving the heating plates a low temperature, the return temperature T _R , which, however, is not determined in the prior art. The differential temperature between the flow temperature T _V and the return temperature T _R adjusts according to the heat loss, but there is also no determination of the differential temperature.

At a mixing point, a large part of the thermal oil, which has the return temperature T _R , mixed with the thermal oil having the output temperature T _{P of} the primary circuit. The control valve is opened until the temperature setpoint, that is, the desired flow temperature T _V , is reached. To convey the thermal oil while a secondary pump is used, which rotates at a constant speed.

• • Bei konstantem Produktionsbetrieb stellt sich ein quasi stationärer Zustand ein.
• • Bei verringerter Wärmeabnahme steigt die Rücklauftemperatur T_R an. Es muss daher weniger Thermoöl aus dem Primärkreis hinzugemischt werden, wodurch sich das Regelventil dem Schließ-Zustand nähert. Die Sekundärpumpe läuft dabei weiterhin mit konstanter Drehzahl und somit unter Volllast, was mit einem hohen Energieverbrauch verbunden ist. Der Thermoölvolumenstrom bleibt somit im Sekundärkreis konstant.
• • Bei gesteigerter Wärmeabnahme sinkt die Rücklauftemperatur T_R und das Regelventil wird entsprechend geöffnet, da mehr Thermoöl aus dem Primärkreis, welches die höhere Ausgangstemperatur T_P besitzt, hinzugefügt werden muss, damit die gewünschte Vorlauftemperatur T_V erreicht wird. Die Sekundärpumpe läuft aber immer noch mit konstanter Drehzahl und fördert somit stets den gleichen Thermoölvolumenstrom.

During operation of the press, the following operating states can be distinguished:

• • In constant production mode, a quasi-steady state is established.
• • If the heat consumption decreases, the return temperature T _{R increases} . It must therefore be mixed with less thermal oil from the primary circuit, whereby the control valve approaches the closing state. The secondary pump continues to run at a constant speed and thus under full load, which is associated with high energy consumption. The thermal oil volume flow thus remains constant in the secondary circuit.
• • With increased heat loss, the return temperature T _R decreases and the control valve is opened accordingly, as more thermal oil from the primary circuit, which has the higher outlet temperature T _P , must be added in order to reach the desired flow temperature T _V. However, the secondary pump is still running at constant speed and thus always promotes the same thermal oil volume flow.

When heating the press, the heating plates and the thermal oil in the secondary circuit are initially cold. The thermal oil may therefore have a relatively high density and viscosity. However, this means that the secondary pump for circulating the thermal oil requires more energy than when the operating temperature of the thermal oil is reached. Thus, the performance of the secondary pump in the secondary circuit must always be designed for the circulation of cold thermal oil, since then the power consumption is highest.

The invention is therefore based on the object to design a press for the production of material plates such that the secondary pump can be designed for lower power and that the energy consumption is reduced during operation.

These and other objects of the invention are achieved with a press according to claim 1. Further preferred embodiments are set forth in the corresponding dependent claims.

• – mindestens eine Heizplatte, welche Heizkanäle zum Hindurchführen von Thermoöl aufweist;
• – eine Sekundärpumpe im Sekundärkreis zum Fördern von Thermoöl zu den Heizkanälen;
• – mindestens eine Messeinrichtung zum Messen der Vorlauftemperatur T_V und der Rücklauftemperatur T_R;
• – eine Einrichtung zum Bilden des Wertes der Differenztemperatur ΔT aus Vorlauftemperatur T_V und Rücklauftemperatur T_R;
• – ein Steuergerät zum Regeln der Drehzahl der Sekundärpumpe in Abhängigkeit von der Differenztemperatur ΔT als Führungsgröße.

As a solution, a press for the production of biomass material plates is specified, wherein the press comprises the following components:

• - At least one heating plate, which has heating channels for passing thermal oil;
• - A secondary pump in the secondary circuit for conveying thermal oil to the heating channels;
• - At least one measuring device for measuring the flow temperature T _V and the return temperature T _R ;
• - Means for forming the value of the differential temperature .DELTA.T from flow temperature T _V and return temperature T _R ;
• - A control device for controlling the speed of the secondary pump in dependence on the differential temperature .DELTA.T as a reference variable.

Furthermore, it is preferred that the press comprises an upper and / or a lower heating plate, which are heated via the same secondary circuit.

As a further solution, a press is provided which comprises an upper and / or a lower heating plate, which are heated via separate secondary circuits.

Preferably, a frequency converter is further provided for controlling the speed of the secondary pump.

The advantages of the press according to the invention are considerable: In production mode, the rotational speed of the secondary pump can be significantly reduced while maintaining the differential temperature .DELTA.T, which is associated with a significant reduction in energy consumption and thus energy costs.

If, for example, the press absorbs only half the power with reduced heat consumption, then, with constant thermal oil volume flow according to the prior art, half the differential temperature would result. However, with a control according to the invention, the thermal oil volume flow can be halved. As a result, significant power savings and thus energy savings can be achieved. The energy savings can be up to 85% of the energy required by the prior art.

Further advantageous measures and embodiments of the subject matter of the invention will become apparent from the following description with the drawing.

The invention is explained in more detail with reference to the drawings. The following is shown in detail:

1 schematically shows a part of a continuous press in a side view.

2 illustrates the state of the art for the interconnection of fluid flows to a hotplate of a press.

3 shows a block diagram for controlling the fluid flows according to the present invention.

In the 1 partially illustrated press comprises a steel band 1 , carried by roll bars 2 , a hot plate 4 with heating channels arranged therein 5 for tempered fluid streams, such as a thermal oil, and a penetration probe 6 for directly measuring the temperature of the heating plate on the roller bars 2 facing side. On the heating plate can also have a hardened rolling plate 3 be arranged on the the rolling rods 2 roll.

Out 2 you can see the interconnection of the fluid flows 15 According to the state of the art. From the flow 10 Thermal oil is the output temperature T _P in only partially illustrated primary circuit 18 provided, which may be 290 ° C by way of example. The thermal oil of the primary circuit 18 is via a control valve 23 the secondary circuit 19 fed. The primary circuit is supplied with energy, for example from a combined heat and power plant, whereas the secondary circuit 19 the one or more hotplates 4 supplied to the press. Before the thermal oil enters the heating plate 4 is its flow temperature T _V at the measuring point 7 determines which example should be 260 ° C. The constant thermal oil volume flow is from a secondary pump 16 driven at a constant speed. By the heat loss in the heating plate 4 the thermal oil has a lower return temperature T _R after its exit from the hot plate. A large part of the thermal oil of the return temperature T _R is in turn the secondary circuit 19 at a mixing point 21 fed. But it can also be a part of the thermal oil via a valve when needed 12 the return 9 be supplied. So that the flow temperature T _V remains constant, is via the opening of the control valve 23 the supply of thermal oil from the primary circuit 18 in the secondary circuit 19 at the mixing point 21 controlled.

For cases where a rapid cooling down of the heating plate 4 necessary is a valve 13 provided that the inlet from a cooling storage 11 einsteuert that includes cool thermal oil. Thus, the heating plates can be brought to a temperature below 100 ° C within a short time.

3 shows a block diagram for controlling the fluid flows according to the present invention. About the lead 10 gets out of the primary circuit 18 Thermal oil to the secondary circuit 19 fed. The primary circuit 18 also includes a measuring station 22 for measuring the volume flow of the thermal oil from the primary circuit 18 in the secondary circuit 19 followed by a control valve 23 , The thermal oil leaves the control valve 23 by way of example with an initial temperature of T _P = 290 ° C.

At a mixing point 21 meets the thermal oil from the primary circuit 18 to a return flow from the secondary circuit 19 , The return flow has a Return temperature T _R of exemplary T _R = 255 ° C, which at the measuring point 8th is determined and sent to a control unit 14 is transmitted (dashed line). It is understood that all temperature data provided are only examples of which it is possible to deviate from.

After the mixing point 21 should that be in the secondary circuit 19 inflowing mixture have a flow temperature of T _V = 260 ° C, which at the measuring point 7 before the thermal oil enters the heating plate 4 is measured and also to the control unit 14 is transmitted (dashed line).

Decisive is a secondary pump 20 with variable speed. The speed of the secondary pump 20 is made using the differential temperature .DELTA.T from flow temperature T _V and return temperature T _R via the control unit 14 controlled (dashed line) so that the differential temperature .DELTA.T remains constant.

Again, the possibility of a quick cooling can be given. Should it come to idling the press, with little or no energy from the hot plate 4 is removed, the speed of the secondary pump 20 by means of the control unit 14 be reduced to a minimum in order to save energy.

In addition to the flow temperature T _V , the heating plate temperature T _H can also be measured. Only when the press has reached a predetermined heating plate temperature T _H , for example, the flow temperature T _V , a Pressgutmatte can be introduced into the press for pressing.

When starting the press, the heating plate takes 4 initially a lot of heat from the thermal oil. Therefore, it is particularly advantageous when starting the press, the secondary pump 20 initially run at maximum speed until a predetermined hotplate temperature T _{H is} reached.

LIST OF REFERENCE NUMBERS

1

 steel strip

2

 roll bars

3

 rolling plate

4

 heating plate

5

 heating channels

6

 penetration

7

 Measuring point flow temperature

8th

 Measuring point return temperature

9

 returns

10

 leader

11

 cool storage

12

 Valve

13

Valve in front 11

14

 control unit

15

 Fluid flow direction

16

 Secondary pump

18

 primary circuit

19

 secondary circuit

20

 Secondary pump (variable speed)

21

 mixing point

22

 Flow-measuring station

23

 control valve

T _P

 outlet temperature

T _V

 flow temperature

T _R

 Return temperature

T _H

 heating plate

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

• DE 102004019429 A1 [0003]

Claims (4)

Press for the production of biomass material panels, comprising the following components: - at least one heating plate ( 4 ), which heating channels ( 5 ) for passing thermal oil; A secondary pump ( 20 ) in the secondary circuit ( 19 ) for conveying thermal oil to the heating channels ( 5 ), - at least one measuring device ( 7 . 8th ) for measuring the flow temperature (T _V ) and the return temperature (T _R ); - means for forming the value of the differential temperature (ΔT) from flow temperature (T _V ) and return temperature (T _R ); A control device ( 14 ) for controlling the speed of the secondary pump ( 20 ) as a function of the differential temperature (.DELTA.T) as a reference variable. Press according to claim 5, characterized in that it comprises an upper and / or a lower heating plate ( 4 ), which via the same secondary circuit ( 19 ) are heated. Press according to claim 5, characterized in that it comprises an upper and / or a lower heating plate ( 4 ), which are separated by separate secondary circuits ( 19 ) are heated. Press according to one of claims 5 to 7, characterized in that for controlling the rotational speed of the secondary pump ( 20 ) A frequency converter is provided.

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