A method for reducing the energy consumption of paper machine flushing water pumps

Abstract

This invention discloses a method for reducing the energy consumption of a paper machine flushing water pump. The method interlocks the paper breakage sensor signal with the flushing water pump's operating signal. Here, 'c' is the paper breakage sensor located before winding, below the paper sheet during normal operation; 'a' is the pump pressure during normal operation; 'b' is the pump pressure during a paper break; and 'o' is the pump's set pressure value. When 'c' = 0 (i.e., the paper machine is operating normally without a paper break), the feedback signal 'o' = 'a', indicating the flushing water pump is in standby mode with a 50% load and a pressure of 2 bar. When 'c' = 1 (i.e., a paper break occurs), the feedback signal 'o' = 'b', indicating the flushing water pump enters its working pressure at 100% load and a pressure of 7 bar. This invention achieves both energy saving and consumption reduction, on-site error prevention, and ensures sufficient water pressure to meet the immediate flushing needs of the paper machine during paper breaks.

Description

Technical Field

[0001] This invention relates to the field of papermaking machines, and more particularly to a method for reducing the energy consumption of papermaking machine flushing water pumps. Background Technology

[0002] Paper machines, such as the Valmet paper machine from Finland, dewater and form wood pulp fibers of a certain concentration during the tissue paper production process. In this process, the felt and forming wire are dewatered under the pressure of the forming rolls. A large amount of water mist is generated at the wet end of the paper machine, which is mixed with fibers and splashes onto the paper machine rolls or frame. Over time, this will accumulate pulp, which will fall off and cause paper breakage, resulting in energy loss and paper holes. Therefore, cleaning water pumps and cleaning water pipes are installed around the paper machine to flush out the accumulated pulp in a timely manner and prevent paper breakage.

[0003] The cleaning water pump has a power of 37KW and an operating pressure of 7bar. In existing technology, the motor runs at full speed and 100% load after starting. Because flushing during normal paper machine operation can cause paper breaks or paper sheet formation problems, flushing is generally only performed during roll changes or when a paper break occurs. Roll changes typically take 30 seconds to 1 minute, so the cleaning water pump spends most of its time doing useless work, resulting in energy waste. The industry's conventional energy-saving method is to manually turn off the cleaning water pump during normal paper machine operation and then manually turn it back on 2-3 minutes before roll changes. The drawback is that frequent manual switching can lead to forgetting to turn it on or failing to turn it on in time to quickly reach the water pressure of 7bar due to a paper break, resulting in either insufficient or prolonged flushing of the paper machine. During paper breaks, even more energy is wasted, and frequent starting and stopping of the motor results in a large current, which accelerates motor aging.

[0004] Therefore, it is necessary to develop targeted methods to reduce the energy consumption of paper machine flushing pumps, and to design more reasonable and scientific control methods for flushing pumps to address the drawbacks of conventional manual start-stop flushing pumps. Summary of the Invention

[0005] Purpose of the invention: In view of the shortcomings and defects of the existing technology, the present invention provides a method for reducing the energy consumption of paper machine flushing water pumps, which can not only save energy and reduce consumption, but also prevent mistakes on site, and ensure that a certain water pressure can be achieved during paper breakage to meet the needs of immediate flushing of paper machines.

[0006] Technical Solution: The present invention provides a method for reducing the energy consumption of a paper machine flushing water pump, characterized in that: the paper breakage photodetector signal and the flushing water pump operation signal are interlocked and controlled, where c is the paper breakage photodetector, located before winding and below the paper sheet during normal operation, a is the pump pressure during normal operation, b is the pump pressure when a paper breakage occurs, and o is the set pressure value of the pump. When c = 0, i.e., the paper machine is operating normally without a paper breakage, the feedback signal o = a, i.e., the flushing water pump is in standby mode with a load of 50% and a pressure of 2 bar; when c = 1, i.e., a paper breakage occurs in the paper machine, the feedback signal o = b, i.e., the flushing water pump enters the working pressure with a load of 100% and a pressure of 7 bar.

[0007] The flushing water pump is installed on the flushing water pipe connected to the clean water tower, and the flushing water pipe is connected to two net flushing water pipes and two blanket flushing water pipes.

[0008] The washing water pipes for the mesh section face the formed mesh on several guide rollers, and the washing water pipes for the blanket section face the blanket on several guide rollers.

[0009] The connection between the forming net and the blanket is provided with a breast roller and a headbox.

[0010] The blanket is attached to the drying cylinder, and the paper sheets of the drying cylinder are connected to the paper roll via a winding cylinder.

[0011] The paper sheet is attached to the crease scraper; the paper cutter eye faces the paper sheet.

[0012] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: Addressing the drawbacks of conventional manual start / stop flushing pumps, this invention designs a more rational and scientific control method for the flushing pump, achieving energy saving and consumption reduction, on-site error prevention, and ensuring sufficient water pressure to meet the immediate flushing needs of the paper machine during paper outages. After improvement using the new interlocking control method, the pump load is reduced from 100% to 50%, and the power is reduced from 37kW to 18.5kW, with 60 minutes of pressure reduction operation every 65 minutes. Annual benefit: 18.5kW * (24h * 60 / 65) * 350 days * 0.69 yuan / kWh = 98977.8 yuan, resulting in energy cost reduction. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the paper machine of the present invention;

[0014] Figure 2 This is a schematic diagram of the structure of the present invention;

[0015] Figure 3 This is a control diagram of the present invention. Detailed Implementation

[0016] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] The present invention provides a method for reducing the energy consumption of the paper machine flushing water pump by interlocking the paper breakage sensor signal with the flushing water pump's operating signal. Here, 'c' is the paper breakage sensor, located before winding and below the paper sheet during normal operation; 'a' is the pump pressure during normal operation; 'b' is the pump pressure when a paper break occurs; and 'o' is the pump's set pressure value. When 'c' = 0 (i.e., the paper machine is operating normally without a paper break), the feedback signal 'o' = 'a', indicating the flushing water pump is in standby mode with a 50% load and a pressure of 2 bar. When 'c' = 1 (i.e., a paper break occurs), the feedback signal 'o' = 'b', indicating the flushing water pump enters its operating pressure at 100% load and a pressure of 7 bar. This method satisfies the need for flushing the paper machine during paper breaks while achieving energy savings and protecting the pump's lifespan.

[0018] The rinsing water pump is installed on the rinsing water pipe connected to the cleaning water tower. This rinsing water pipe connects to two wire section rinsing water pipes and two blanket section rinsing water pipes. The wire section rinsing water pipes face the forming wire on several guide rollers, and the blanket section rinsing water pipes face the blanket on several guide rollers. A breast roller and headbox are located at the connection between the forming wire and the blanket. The blanket is bonded to the drying cylinder, and the paper sheet in the drying cylinder is connected to the paper roll via a winding cylinder. The paper sheet is bonded to the creping doctor blade; the paper cutter faces the paper sheet.

[0019] This invention addresses the drawbacks of conventional manual start / stop flushing pumps by designing a more rational and scientific control method. This method achieves energy savings, prevents mistaken starts, and ensures sufficient water pressure to meet the immediate flushing needs of the paper machine during paper outages. After the improvement using the new interlocking control method, the pump load is reduced from 100% to 50%, and the power is reduced from 37kW to 18.5kW. The pump operates at reduced pressure for 60 minutes every 65 minutes. Annual savings: 18.5kW * (24h * 60 / 65) * 350 days * 0.69 yuan / kWh = 98977.8 yuan, resulting in significant energy cost reductions.

Claims

1. A method for reducing the energy consumption of a paper machine flushing water pump, characterized in that: The paper breakage photodetector signal and the flushing water pump's operating signal are interlocked. 'c' is the paper breakage photodetector, located before winding and below the paper sheet during normal operation. 'a' is the pump pressure during normal operation, 'b' is the pump pressure when a paper break occurs, and 'o' is the pump's set pressure value. When c=0 (the paper machine is operating normally without a paper break), the feedback signal 'o'=a, meaning the flushing water pump is in standby mode with a 50% load and a pressure of 2 bar. When c=1 (the paper machine experiences a paper break), the feedback signal 'o'=b, meaning the flushing water pump enters its working pressure, with a 100% load and a pressure of... The force is 7 bar; the rinsing water pump is installed on the rinsing water pipe connected to the purifying water tower, and the rinsing water pipe is connected to two wire section rinsing water pipes and two blanket section rinsing water pipes; the wire section rinsing water pipes face the forming wire on several guide rollers, and the blanket section rinsing water pipes face the blanket on several guide rollers; a breast roller and a headbox are provided at the connection between the forming wire and the blanket; the blanket is attached to the drying cylinder, and the paper sheet of the drying cylinder is connected to the paper roll through the winding cylinder; the paper sheet is attached to the creping doctor blade; the paper cut-off eye faces the paper sheet.

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