Valve Stand with Multi Orifice Mixer. Zone Control Malfunction. 3 Way Valve Malfunction. Mixing Degree Wave. Toyo-Sun Machinery Co., Ltd.

Transcription

1 Valve Stand with Multi Orifice Mixer Zone Control Malfunction 3 Way Valve Malfunction Mixing Degree Wave Toyo-Sun Machinery Co., Ltd.

2 On this occasion, our company has developed the Online Digital Hot Rolling Oil System with NEVI system. This system secures the oil s maximum plate-out to the roll by using multi orifice mixers, and optical technology for each mixing degree according to the density. features 1. Mixing degree digitalization 2. Most suitable plate out 3. Early warning of suffocation factor 4. Oil consumption cut 1.Summary The effectiveness of the hot rolling oil is greatly affected by the density and the mixing degree (the degree of water and oil mixing condition). To obtain an optimum mixing degree, first, it is necessary to adjust the mixing degree with the multi orifice mixer. Then, the relationship between the oil s plate-out to the roll and the transparency number by density have to be obtained by using optical technology that expresses numerically the transparency number of the solution. According to the results of this, the mixing degree appropriate to obtain the maximum plate-out to the roll can be regulated online. Our company s system is a hybrid system comprised of a multi orifice mixer and a digital sensor. 90 / Stroke 2.Oil and Water Mixing (Injection Mixer) As shown in FIG.1, the Injection Mixer is comprised of an orifice and a diffusion chamber, and it is one of the most important devices in the rolling oil system to get the oil and water mixed. If the orifice s diameter is small, the solution will be well mixed. If the orifice s diameter is big, the water and oil will run into the nozzle headers in a separated state. According to the plate s width the nozzles of both sides will change to [wide], [middle], and [narrow]. If the spray is stopped, the quantity of water will change and as a consequence, the water and oil mixing condition will change and thus alter the oil s plate-out to the roll. The Online Digital System developed by our company, combined with the multi orifice mixer, is able to secure the maximum plate-out efficiency of the oil. FIG.1 Orifice Diffusion Room room Emulsion Exit 0.5 Orifice 1

3 3. Characteristics and FIG.2 Operating Principles In FIG.2, the basic principles of the optical-technology-using Online Digital System are shown. First, the water and oil mixing degree is numerically represented by the transparency number. If its density is high and it is well-mixed, the light will not pass through the solution easily; but, if its density is low and it is not well-mixed the transparency number will increase. The density is numerically represented by using the light reflected in the oil s particles. The density and mixing degree can be measured at the same time by taking a sample of the emulsion in the square-shaped cells. From the nozzle headers shown in FIG. 1, extract a sample of emulsion with the square-shaped cells. Then, obtain its numerical value using the portable kit D DKIT II and create a list of transparency number by density (as shown in Table 1). At the same time, prepare a test plate (square of 100 mm ) for each nozzle spray, and measure the oil s plate-out in each nozzle. If there is too much plate-out variation between each test plate it is because of bad mixing, in that case reduce the size of the multi orifices. If the size of the orifices is too small, plate-out variation will disappear in each nozzle, but the plate-out will also decrease. An appropriate range shows TABLE 1 which is permissible between ±5%. This value varies depending on each the density and type of each oil. If the water temperature is high, it might mix too much causing a decrease in the transparency number and in the plate-out. The values shown in TABLE 1 represent the maximum plate-out possible. A maximum plate-out can be obtained with minimum oil consumption and keeping variations limited. Transparency number 濃度別透過線数表 according to density TABLE % 0.3 % 濃度 :(0.1%) 濃度 :(0.3%) 0.5 % 濃度 :(0.5%) 0.8 % 濃度 :(0.8%) 1.0 % 濃度 :(1.0%) 4.Objective Until now, hot rolling oil systems efficiency has been judged by their draft decrease rate of the rolling force. The decrease rate s amount has been controlled only by high/low densities for many years. However, recently many researches and experiments have found that the mixing degree has a great influence not only on the draft decrease rate, but also on the plate shape and its quality, proving this way the importance of the measurement of the mixing degree. The mixing degree may vary even though the density is the same because of other factors such as the water temperature and hardness. Also, after the sample is taken, the oil and water separate as time passes making the measurement of mixing degree impossible. The objective of our Online Digital System is to measure the mixing degree online and quantify it numerically. In addition, by detecting with the online sensor small infiltrations of oil in the carrier water when off-loading, accidents such as slips of the strip and biting failures can be avoided. 2

4 Air pilot FIG.3 Super thin combined header Water wrapping 3 Online direct sensor Air solenoid unit S.V unit Auto multi orifice mixer Rack & pinion type air cylinder 4 Reducing valve Check valve 3way valve 1 Valve stand Relief valve Flow meter Water pump Oil pump 2NEVI SYSTEM OHRO 回路図 Heater 5 Oil metering and water pump unit ONLINE DIGITAL SYSTEM CIRCUIT DIAGRAM Composition The Online Digital System can be divided broadly in 5 parts: 1 Valve stand with built-in multi orifice mixer 2 NEVI system, 3 Online Direct sensor, 4 D D KIT II, 5 Oil metering and water pump unit Hindrance causes with related information Part Ⅰ The following items all lead up to strip quality deter 10 ration or a big trouble Toyo-Sun online digital system with NEVI system can grip visually suffocation factors to proper hot rolling oil system. By digital or the board of pictures in the operator room. 1.Nozzle clogging 6.Water flow rate change by caused by pressure change 2 Nozzle deterioration 7.Change of density and mixing degree 3.Unbalance of density between 8.Change of density actuating Top & Bottom rolls sprayed defect of valve 4.Unbalance of mixing degree 9. Intermix of oil into spray between Top & Bottom rolls sprayed line caused by defect of 3way valve when off rolling 5. Metering pump deterioration 10.Pipe constriction 11.Defective water seal 12.Change of amount of plate out caused by water temperature 13.Defective zone control b dividing valves Toyo-Sun Machinery Co., Ltd , Matsugashima-nishi, Ichihara-shi, Chiba, Japan TEL FAX URL Distributor:

5 Blind spots to conventional hot rolling oil system 1.Heavy reliance on density control 2.Excessive dependence on rolling force 3.Disregard of water quality & quantity control 4.Excessive expectation on the oil type 5.Desregard of zone control 6. Poor interest in oil consumption 7.Disregard of the importance of water seals NEVII Syysstteem Deessccrri ipptti ioon & Feeaatturreess A. The NEVI system helps us identify the cause that hinders proper rolling oil. As shown in FIG. 1, the waves of each type of parameter and the optimum standard degree of mixing with some allowance are displayed on the screen. We take the degree of mixing wave as a standard, and in case there are protruding actual waves, the system s computerized process shows abnormal signals through images that tell us which factor is causing the problem. Normal Condition Rolling force reduction wave FIG. 1 Actual degree of mixing wave Optimum standard degree of mixing wave Plate temperature Water pressure Water temperature Water quantity Oil quantity Density 3-way valve B. FIG2 shows us an actual wave protruding from the standard wave. In part (A) of the image the continuous line protrudes left from the optimum standard degree of mixing; this shows us that for some reason, the water and oil are over-mixing, the light s transparency number is small, and the plate-out is going down. Contrariwise, in wave (B) we can see that the water quantity is diminishing due to nozzle clogging and this is increasing the water temperature affecting the water-oil mixing. Thus, oil s plate-out variations become a matter of concern. Part (C) shows us oil infiltration in the water spray during off-rolling. There s a possibility that the next plate entering will slip. Abnormal Condition1 FIG. 2 Nozzle deterioration high water temperature water/oil pump malfunction Nozzle clogging low water temperature water/oil pump malfunction Oil infiltration in the water Transparency Number (Degree of Mixing) C. FIG.3 is an example of a poor zone control and 3-way valve malfunctioning. The valve in charge of the zone control leaks, increasing the water flow rate, and thus changing the degree of mixing. The water and oil over-mix and make the actual wave to protrude left from the standard wave as shown in (A). In (B) we see that even though a normal electric given to 3-way valve, in case the wave is corrupted, an alarm signal that indicates that the 3-way valve is not working properly is produced. Zone control malfunction Abnormal Condition2 3-way valve malfunction FIG 3 Transparency Number (Degree of Mixing)

6 D. FIG.4 is an example where water seal malfunction is suspected. Due to a continuous leak of coolant water, the rolling force reduction rate becomes lower everything but the rolling force reduction wave is normal, and a wave similar to the one in FIG.4 is formed. In other words, the line that was supposed to be reduced until the original wave becomes the actual line. Abnormal Condition3 Rolling force reduction wave FIG 4 Actual degree of mixing wave Optimum standard degree of mixing wave Plate temperature Water pressure Water temperature Water quantity Oil quantity Density 3-way valve Attention: The NEVI system stands for, Navigator, Evaluate, Visual, Indicator. Our system uses a degree of mixing wave with a certain range as a navigator; it permit us visualize the degree of mixing in the form of a continuous line, and in case it protrudes from the determined range it helps us evaluate the degree of mixing. E. Example of Part Ⅱ: Factors that hinder an optimum rolling oil a.nozzle Clogging A total flow rate reduction of 0.8% in the header, and a change of 200 units in degree of mixing can be detected. FIG 5 Degree of mixing value: 4000 (Flow rate of nozzle #2:4.3l/min) The throttle valve closes gradually Degree of mixing value : 4200 ( Flow rate of nozzle #2:4.0l/min ) B.Nozzle Deterioration A total flow rate increase of 1.6% in the header, and a change of 200 units in degree of mixing can be detected. Degree of mixing value : 4000 ( Flow rate of nozzle #2:4.3l/min) The throttle valve opens gradually Degree of mixing value : 3800 ( Flow rate of nozzle #2:4.9l/min)