METHOD FOR MONITORING THE MANUFACTURE OF WOOD-BASED PRODUCTS WITH REGARD TO THE EMISSION OF VOLATILE ORGANIC COMPOUNDS, AND DEVICES FOR MONITORING THE EMISSION OF VOLATILE ORGANIC COMPOUNDS IN THE MANUFACTURE OF WOOD-BASED PRODUCTS

Abstract

A method for monitoring a manufacture of wood-based products includes at least one pressing process with regard to the emission of volatile organic compounds from the wood-based products, in which the concentration of the volatile organic compounds is detected during the manufacture. The concentration of the volatile organic compounds is detected during an extraction of product parts or of a product surface using a measurement method from the field of TDLS (Tunable Diode Laser Spectroscopy), FTIR, NIR, IMS or photoacoustics, that the detected concentration of the volatile organic compounds is fed to a mathematical model, and that parameters such as product thickness, areal density, production feed rate, flow rate in an extraction of product parts or of the product surface and the moisture content of the raw materials for the wood-based products are determined before the pressing process and are also fed to the mathematical model.

Claims

1. A method for monitoring the manufacture of wood-based products, including at least one pressing process, with regard to the emission of volatile organic compounds from the wood-based products, in which the concentration of the volatile organic compounds is detected during manufacture, wherein the concentration of volatile organic compounds is measured during an extraction of product parts or of a product surface using a measurement method from the field of TDLS (Tunable Diode Laser Spectroscopy), FTIR, NIR, IMS or photoacoustics, the detected concentration of volatile organic compounds is fed into a mathematical model, and parameters such as product thickness, areal density, production feed rate, flow rate in an extraction of product parts or of the product surface and the moisture content of the raw materials for the wood-based products are determined before the pressing process and are also fed into the mathematical model.

2. The method according to claim 1, wherein the parameter of temperature of existing heating circuits of a pressing device is additionally fed to the mathematical model.

3. The method according to claim 1, wherein the parameter of the degree of gluing of existing product layers is additionally fed to the mathematical model.

4. The method according to claim 3, wherein the molar ratio of the glue used in the product layers is fed to the mathematical model.

5. The method according to claim 3, wherein the proportion of cover layers or of middle layers in relation to the total product is fed to the mathematical model.

6. The method according to claim 3, wherein the amount of urea added to the product layers is fed to the mathematical model.

7. The method according to claim 1, wherein an emission of the product parts corrected by the mathematical model or an emission from the product surface is referenced against a standardised laboratory emission test method.

8. The method according to claim 7, wherein a concentration of the volatile organic compounds corrected by the mathematical model is used for open-loop and closed-loop control of the manufacture of wood-based products, including at least one pressing process.

9. The method according to claim 1, wherein it is carried out in situ when a suitable measurement method is selected.

10. A device for monitoring a manufacture of wood-based products with respect to the emission of volatile organic compounds from the wood-based products, preferably for carrying out the method according to claim 1, wherein the device has components, a transmitting unit and a receiving unit, arranged on opposite sides of an extraction line carrying product parts, in that these components are connected to the extraction line via pipe sections, and in that at least one flushing device is associated with the pipe sections.

11. The device according to claim 10, wherein the transmitter unit comprises at least one laser source for the TDLS (Tunable Diode Laser Spectroscopy) measurement method.

12. The device according to claim 10, wherein the flushing device has flushing pipes which can be supplied with compressed air.

13. The device according to claim 12, wherein the pressurisation with compressed air is alternating.

14. The device according to claim 12, wherein the flushing pipes are inserted into the pipe sections for connecting the transmitter unit and receiver unit to the extraction line.

15. The device according to claim 12, wherein each flushing pipe has a free end with a conical design that protrudes into the extraction line.

16. A device for monitoring a manufacture of wood-based products with regard to the emission of volatile organic compounds from the wood-based products, in particular for carrying out the method according to claim 1, wherein the device has at least one protective housing for receiving the wood-based products, in that transmitter unit and receiver unit are arranged on opposite sides of the protective housing, and in that at least one air guiding device is associated with the protective housing.

17. The device according to claim 16, wherein the transmitter unit and the receiver unit are arranged in a plane above the wood-based products.

18. The device according to claim 16, wherein at least one fan inserted into the housing wall is provided as the air guiding device.

19. The device according to claim 18, wherein the fan is arranged above the transmitter unit and receiver unit.

20. The device according to claim 18, wherein the transmitter unit comprises at least one laser source for the TDLS (Tunable Diode Laser Spectroscopy) measurement method.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Exemplary embodiments of the device according to the invention are shown in the drawing, in which:

[0040] FIG. 1: shows a schematic side view of a continuous-strand production line for wood-based products, to which a device according to the invention is assigned for surface monitoring;

[0041] FIG. 2: shows a schematic side view of the monitoring device according to the invention according to FIG. 1; and

[0042] FIG. 3: shows an alternative design of a monitoring device for monitoring the continuous-strand production line in FIG. 1.

DETAILED DESCRIPTION

[0043] Manufacture of the continuous strand 2 begins in a forming line 1 with spreaders 1a. The continuous strand 2 emerges from the forming line 1 in the form of a chip cake and is fed to a press system 3 using suitable conveyors. After leaving this press system 3, the continuous strand 2 is in compressed form. It is fed along arrow 9 to a trimming saw 4 and a diagonal saw 5.

[0044] The monitoring device according to the invention is assigned to the saws 4 and 5. Specifically, it is assigned to an extraction system 6 of the saws 4 and 5. Each saw 4 and 5 initially has its own extraction channel 6, 6, which then open out into the common extraction line 6, designed as a pipe. The monitoring device according to the invention has components 7, which are arranged on both sides of the extraction line 6 (FIG. 2). The components 7 are connected to a control cabinet 8 for their control.

[0045] FIG. 2 shows the extraction line 6 in portions. The components 7 are arranged on both sides of this extraction line 6; these components 7 are a transmitter unit 10 and a receiver unit 11.

[0046] The transmitter unit 10 and the receiver unit 11 are connected to the extraction line 6 via pipe sections 12. Each pipe section 12 runs from the transmitter unit 10 or from the receiver unit 11 to the surface of the extraction line 6, wherein an opening is arranged in the wall of the extraction line 6 in the attachment region of the pipe section 12 at the surface. The transmitter unit 10 and receiver unit 11 are thus connected to the inside of the extraction line 6.

[0047] Flushing pipes 13 are inserted into the pipe sections 12. The flushing pipes 13 have a slightly smaller diameter than the pipe sections 12 so that the flushing pipes 13 can be arranged inside the pipe sections 12. The free ends of the flushing pipes 13 protrude into the interior of the extraction line 6, and their free ends are conical.

[0048] A volume flow sensor 14 is also assigned to the extraction line 6. Said sensor is attached, below the pipe section 12 for the transmitter unit 10, to the extraction line 6, protruding into the interior of the extraction line 6.

[0049] In the exemplary embodiment according to FIG. 3, no extraction line 6 is provided for the monitoring device. A protective housing 15 is used here, through which the continuous strand 2 is guided. A transmitter unit 10 and a receiver unit 11 are again arranged on the outside of the protective housing 15. The arrangement is provided at a height above the continuous strand 2, which rests on a substrate 16. For example, a laser source is used as the transmitter unit 10 and the laser beam emitted by the transmitter unit 10 is illustrated by the dashed line 17. It runs through the inside of the protective housing 15 to the receiver unit 11.

[0050] Another volume flow sensor 14 is arranged in the protective housing 15. It is arranged above the plane of the transmitter unit 10 and receiver unit 11 on a wall of the protective housing (15). Fans 18 are also arranged above this plane, in the ceiling of the protective housing 15.