JPS5997485A - Controller for exhaust of building with dust generating source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Does the present invention include dust sources? Buildings such as metal smelting furnaces, melting furnaces, foundry facilities, etc.? The present invention relates to an exhaust gas control device that can maintain a good working environment in a factory building, etc., while saving power.

Equipment that generates large amounts of fume, dust, etc.? Factories that own large-sized cicada air (ventilation) equipment for dust removal are necessary for the health management of workers and product management. Conventionally, on the factory exhaust installation side, a hood was attached to the dust source, and the dust-containing air taken in from each hood was sent to the dust collector through the exhaust collection duct. In this case, the exhaust fan is installed with a capacity that can satisfy the air volume 1 required by each hood. In other words, the capacity of the exhaust fan is designed to match the maximum air volume, which is the total air volume of each hood, so that the necessary exhaust air can be generated even when several dust generating devices are in operation. However, since there are not always thorns in equipment that generate dust, if a blower designed for this maximum air volume is in constant operation,
Even if a measure was taken to individually adjust the amount of suction and exhaust to each hood, the power required to operate the exhaust fan would be extremely large.

The purpose of the present invention is to reduce the power of the exhaust fan in such a dust-generating factory. The objective is to maintain and achieve the desired working environment without making major changes to existing equipment. For this purpose, the present invention includes an exhaust collection duct leading to a dust collector, a plurality of exhaust hoods connected to the exhaust collection duct, and means for adjusting the amount of exhaust air sucked into each exhaust hood according to the dust generation situation. , an exhaust fan for creating negative pressure in the exhaust collection duct, an exhaust capacity control device for this exhaust fan, and a microcontroller that monitors the dust generation status and the pressure drop of the dust collector and calculates the required air volume based on this. A computer device and an exhaust control device for a building having a dust generation source, which converts the calculation results of the computer into a chemical flow value and automatically controls the ventilation capacity control device. be.

The details of the present invention are as follows: 4 electric furnaces for metal melting and 4 heat retention furnaces for mold injection. An embodiment of a foundry will be explained one by one in comparison with a conventional method.

Fig. 1 is a system diagram of the conventional method, and 1 indicates the exhaust hood metal, and these are the electric furnaces EF1 to KF4 and the heat retention furnace H.
They are installed locally so that all of the generated dust from Fi to HF4 can be individually sucked. Each exhaust hood 1 is connected to an exhaust collection duct 3 via an electric damper 2, and this exhaust collection duct 3 is connected to a ticket collection device 4.
The air is exhausted from the entire system by a large exhaust fan 5, and is discharged outside the system through six silancers. As mentioned above, this boat ejection machine 5 has a capacity that can satisfy the required exhaust air volume even when the electric furnaces and heat-retaining furnaces are operated simultaneously. An example of the conventional exhaust operation mode in this foundry is as follows.

First, the operation of the four electric furnaces involves the raw material input process,
It is divided into six stages: a melting process and a stopping process (however, one of the seven is a preliminary furnace, so the operation is normally stopped). Then, the air volume to be discharged from the valley exhaust hood 1 of each electric furnace is determined as raw material input process = 9000MM, melting process = RO [JOCMM, stop process - 400MMF leakage consideration), and electric dampers are installed in each process to match this. ／ゝ2 Centralized control is performed using a central control panel, or control is performed using a local control panel. Two actual electric furnaces are operated at the same time during the raw material input process, and an operation schedule is set so that the time for each melting furnace 8 is postponed so that they do not operate at the same time.

Similarly [the operation of each of the four Hofu furnaces is divided into a receiving process, a tapping process, and a stopping process, and the air volume discharged from each exhaust hood 1 is 10,000 MM for each process.
500 CMM and 40 CMM, and the opening degree of each electric damper 2 is adjusted using the central control panel or hand panel on the air volume side.

This design air volume can be summarized as shown in Table 1 (the circled area indicates the operating volume). Assuming that the following operating conditions are adopted, υ1. wind machine 5
The design air volume is 514.00 MM, and an IM capacity of, for example, 52,000 MM is installed to meet this requirement.

However, according to this conventional equipment, there are always situations that require a design air volume of 51,400 MM '5 as circled in Table 1.
Since the constant air flow operation of 1400 MM continues, the constant air flow operation continues without taking into account the change in pressure loss due to clogging in the frozen dust collector 4, so most of the operating power of the exhaust fan 5 is wasted. The reality is that 1ζ
. Figure 2 shows the change in the actual required air volume over time during the operation time in the above-mentioned foundry process.
Continue operating at 00MM.1. On the other hand, the actual hourly average required air volume is about 20,000 MM, which shows how large a difference exists between the actual required air volume and the capacity of the installed exhaust fan. However, with conventional equipment, as shown in Figure 2, there are times when the entire air volume near the maximum design air volume is required (at 20 minutes, 90 minutes, 165 minutes, etc.), so this 52,000 MM Fig. 3 is a system diagram when the present invention is applied to the above-mentioned foundry. Surprisingly, according to the invention, compared to the conventional equipment shown in Figure 1, the calculation results will be described in detail later,
Power costs are reduced by 76.9%, and similar dust removal can be achieved with only 10 to 30% of the power required to drive conventional equipment, achieving an extremely large energy-saving effect.

In Figure 6, the same reference numbers and symbols as in Figure 1 are the same as in Figure 1, 7 is the wind speed detector, 8 is the differential pressure detector of the dust collector, 9 is the dust concentration detector, and 10H control. Microcomputer for N, 11i11fflJlz - board, 1
2 represents the exhaust capacity control panel (thyristor inverter panel in this embodiment) of the exhaust fan, and the 13 electric motors of the exhaust fan; most simply, a, the current type thyristor inverter for controlling the rotation speed of the electric motor 16; It is practical to adopt a frequency control method using the panel 12 and thereby modify the existing exhaust fan to a variable air volume fan. If the electric damper 2 has already been installed, it can be used in its entirety, and if a system has already been installed in which information is managed in the central control room for operations within the factory, this can be used. It can be used to incorporate into the source of the control system of the present invention.

For example, electric dampers 2 for adjusting the air volume installed in each local exhaust hood 1 at this prayer factory operate in accordance with the processes shown in Table 2 below in the electric furnace system and the heat retention furnace system. Assuming that each process in both systems is identified, the operation switch of each device must be turned on.
= OFFFF state quantity detection can be summed up, and the exhaust I required for each exhaust hood 1! can be easily identified.

Each detected octopus is sent to a relay board 11, converted into a non-voltage contact signal 14, and then written to a control microcomputer 10 to sum up the detected ON-FF signals and identify them. At the same time, the opening degree of each electric damper 2 for adjusting air volume is determined from the relay board 11.

The control microcomputer used in the present invention has the following functions.

(11) Each process of each system is constantly monitored and identified using a non-voltage contact signal 14 (scanning function).

Electric furnace system raw material input process Σ(a+ + a2+a3 ], =3
' q =9000MM melting process Σ(a+ +
a2+as), =1 q=3000MM.

Stop process Σ(al+a2+a3)i=o q”
400MM heating furnace system receiving process Σ(b,-)-b21. =2 r=1
0000MM tapping process Σ(bl+b2)1=1
r= soo 0MM stop process Σ(b, +b2
), =Or=400MMHere, i indicates the furnace number, and the required air volume is stored in advance in the control microcomputer for each furnace number.

(2) Calculate the required exhaust air volume of the exhaust fan.

Required air exhaust from the exhaust fan iQ=Σ(q+r・)1 1 (3) Static pressure when the exhaust fan has a constant air volume.

As shown in Figure 3, from the exhaust hood 1 population to the static pressure △P1 at point A 1 of the exhaust collection duct B on the upstream side of the dust collector 4 and on the downstream side of the final hood. do.

1, the pressure loss before and after the dust collector t4 is assumed to be ΔP2.

In addition, the remaining static pressure is set to P3.

This △P, △P2, △P3 E, constant air volume Q. Since this shows the required pressure loss when operating at

Quiet pressure △Po−△P1+△P2+△P at constant air volume of exhaust fan 5
3 (4) Required static pressure in the air passage system when the required amount of exhaust is Q (△P
) is calculated using the total order equation.

ΔP - ΔP, + △"2 '(Q/Q, ) + △P3(Q
/Qo)2(5) Calculate the required rotation speed N of the electric motor 3 for the exhaust fan. In addition to this N, the rotation drN of constant air volume operation is
.

Then, it is calculated using the following formula.

N=kXNo
This output signal is 15? It is transmitted to the thyristor inverter board 12.

(6) - 10,000, the signal from the wind speed detector 7 installed at point B of the exhaust collection duct 3? , During the control period, we sampled 10 times, removed the highest value and the lowest value, and calculated the average wind speed from the remaining 8 data. This is detected and multiplied by the hydrodynamic equivalent diameter (DJ') of the duct 6 to convert it into an air volume.

Wind ffi CLM” measured during control time
2~=-xpxv (7) Calculate the deviation between the measured air volume QM and the required air volume Q.

Deviation e=Q-Q'' (8) Is there a dead zone around the required air volume Q? Set.

Upper limit band kLH, lower limit band? Measured as LL. When M gets between the duck and LL, consider Q=QMJ.

When Flies < Q (LH < e), make corrections using integral and proportional system 1 wholesale. Constant of proportionality k K+, integral constant? :y, wK2,
As the number of convergence calculations n, N: N -K, e, -K2Σetn=l Q -Q l/10 When QL>Q (Lt<e), correction is added by injection and proportional control.

N=N-, et+2Σet,.

et= l Q Q l/10 As a result of this correction operation, the secondary microcomputer 1
The output signal is outputted as a current value of 01''t4 to 20 mA, and this output signal is sent to the iris inverter board 12 to control the number of rotations of the electric motor 16.

(9) Arrow, air volume, analog data of detector 7? Enter, return to (6) above, and measure the wind Fff Q
is repeated at 1, which hits the dead zone around the predetermined wind sensitivity Q trench.

More functions? The control microcomputer 10 controls the variable speed of the exhaust fan 5 to adjust the required air volume according to the operating conditions of the electric furnace system and the heat retention furnace system, taking into account the reduction in air volume due to clogging of the dust collector. This is automatically ensured by operation, and it is effectively avoided that the exhaust fan is driven to flow more air than necessary.

In order to make this control even more effective in terms of environmental protection, a dust concentration detector 9 (for example, a 180° backscatterometer consisting of a light emitter and a light receiver can be used) is installed in the workplace. It is also possible to install a full control system that suddenly increases the number of rotations of the exhaust fan by 50 degrees regardless of the operating pattern. That is, 00) For example, during the correction calculation in (8) above, the turbidity C8 is calculated from the air dust concentration detector number sent from the dust concentration detector 9 using the optical turbidity filter. , if the allowable value is C6-u
, i y exceeds the full capacity of the exhaust fan 5 (design air volume)
Or perform cascade control to operate at the set air volume.

Furthermore, when the clogging of the dust collector 4 reaches a dangerous level, it is also possible to issue an alarm using all the measured values from the differential pressure detector 8 mentioned above. This can be done by setting an alarm level in the control microcomputer 10, comparing it with the measured value from the differential pressure detector 8, and issuing an alarm. If the alarm level is directly set on the differential pressure detector 8, the fixed value level will be ineffective during variable air flow control, so this must be avoided.

The dust generation source of the present invention with the above configuration? According to the exhaust gas control system for a building, the above-mentioned objectives are effectively achieved, and, for example, in the case of the factory of the above embodiment, the power saving rate reaches 76.9%. The calculation criteria is described below: Capacity of exhaust fan 5: 5140 CMM x 500 Aq
Maximum pressure loss of 2 x 400 KW machines installed in parallel 4: 150m1! Aq at
20000MM constant pressure point (A) static pressure 200 +g
x Aq at 4000 CMM-, in conventional constant air flow operation (equipment shown in Figure 1), 5140
500 6120
△P1+△P2+ΔP3=200+150+150=5
00mmAq △P=△P, 10△P2 (Q/QO) + △Ps (Q/Q
, o) 2-= 200 + 1 so (200015
140) -4-1so (2000/514o)2=
281.1 mm Aq However, based on the simultaneous usage rate, hourly average air volume = 20000 MM
Inverter efficiency = 0.95 Motor efficiency = 0.9'fx. In other words, the shaft power 1d is reduced from 717.8 KW to 165.8 KW. Electricity fee = 20 yen
/KWH is operated for 4000 hours a year, conventional equipment 20'V/KWHX 717.8KW
X 4000 Hr/If:= 57,424.00
0 yen/year Equipment of the present invention 20 yen/KWHX 165.8. K.W.
X 4000 Hr/year = 13,264,000 yen/
In 2015, the power saving cost was 44,160,000 yen/year, and the power saving rate was 76.9 cm, which shows that an extremely large amount of cost and energy savings can be achieved.

[Brief explanation of the drawing]

Figure 1 is an equipment layout system diagram showing an example of exhaust equipment in a conventional foundry, Figure 2 is a diagram of the required air quality over time for the equipment in Figure 1, and Figure 3 is the equipment of the present invention. f: An example of the case where it is applied to the foundry shown in Figure 1 is of course shown. 1... Exhaust hood, 2... Electric guava, 6... Exhaust collection device, 4... Dust collector, 5... Exhaust fan,
6... Xilencer, 7... Air volume detector, 8...
Differential pressure detector of dust collector, 9... Dust concentration detector, 10
... Microcomputer for control@1, 11... Relay board, 12... Exhaust capacity control device (Sirisk inverter board), 16... Electric motor procedure amendment (voluntary) May 1981 4th Patent Office Commissioner Kazuo Wakasugi 1. Indication of the case 1989 Patent Application No. 209076 2. Title of the invention Exhaust control device for a building with a dust generation source 3. Relationship with the amended person's case Patent applicant Name: Representative of Takasago Thermal Engineering Co., Ltd.
Landscape Section 4, Agent 〒162 (2) Column for brief explanation of drawings in the specification (3) Drawing 6, contents of amendment (1) The detailed description of the invention is amended as follows. (A) Formula % Formula % on page 15, line 4 of the specification "Correct to e=1Q-Q1/Qo, j. ← N Formula % Formula % () on page 13, line 7 of the specification Correct the formula [et=IQ-Q 1/10J to F et=IQ Q 1/QoJl on page 15, line 8 of the specification. (b) Insert the following phrase between lines 8 and 9 on page 15 of the specification. Insert: "Example of calculation performed by microcomputer 70-f: Shown in Figures 4 to 6." (2) The brief description of the drawing is corrected as follows. (b) On page 17, line 11 of the specification, replace “This is a system diagram.” with “
The system diagram and FIGS. 4 to 6 are a series of flowcharts showing examples of operations performed by a microcomputer when controlling the equipment of the present invention. (3) Figure 6 of the drawing is deleted and attached Figures 6-6 are added.

Claims (1)

[Claims] An exhaust collection duct leading to the dust collector, a plurality of exhaust hoods connected to this exhaust collection duct, a means for adjusting the amount of exhaust air sucked into each exhaust hood according to the dust generation situation, and An exhaust fan for creating negative pressure, an air exhaust capacity control device for the exhaust fan, and a microcomputer device that monitors all pressure losses in dust generating factories and dust collectors and calculates the required air volume based on this. An exhaust gas control device for a building that is connected to a dust generation source, wherein the calculation result of the computer is converted into a current value to automatically control the ventilation capacity control device.