JP6454838B1 - Water level detection device and water level control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable water level detection device that operates without contact. A water level detection apparatus includes a flat reflection type water level meter 6 and optical sensors 1, 2, and 3. The flat reflection type water level gauge 6 is made of glass having prism-shaped irregularities on the back surface in contact with water. The optical sensors 1, 2, and 3 detect the water level by irradiating the flat reflective water level gauge 6 with light from the surface and detecting the reflected light. [Selection] Figure 5

Description

  The present invention relates to a water level detection device and water level control suitable for a boiler.

There are two types of boilers: steam boilers and hot water boilers for hot water supply. The boiler is in operation 24 hours a day, and is only stopped during inspections. In order to drive, it is necessary to memorize complicated operation procedures and to operate correctly, so the qualification and proficiency level of a boiler engineer is indispensable. Inspection and management of the water level gauge is to be performed every day. The water level in the boiler body tank must not be too high or too low, and it must always maintain a certain level. If it is too high, water will be mixed in the steam and a water hammer will occur. If it is too low, there is a danger of airing, so a low water level alarm is sounded and combustion is automatically stopped. Therefore, the water level is always controlled using a float type water level sensor and an electrode type sensor.

The boiler engineer has a rule that always monitors the water level meter and conducts daily inspection and maintenance in case of sudden failure. Because there are many fuel and burner combustion, ventilation, steam pressure, and inspection items, the only way to prevent boiler accidents is to rely on human monitoring at this time. In particular, management of the water level is particularly important, and there is a problem whether there is no method for monitoring instead of a person who monitors 24 hours a day, or whether there is a method for notifying a person of the occurrence of an abnormality without delay.

To solve the problems of water level management, automation is necessary, but the hurdles are very high. It is desirable not to be a limit switch type having a mechanical contact but to be an electrode type, that is, an electric contactless one. If there is no contact, there is no deterioration over time, so the service life is much better.

To realize this, it is necessary to consider using today's advanced electro technology and physical phenomena such as sound waves and light waves. Therefore, we decided to consider a combination of a water level gauge that reads using the optical action of a flat reflective water level gauge 6 that has been installed in the boiler, and an optical sensor.

An experimental device was made by attaching an optical sensor that discriminates black and white using a combination of the flat reflection type water level meter 6 and the electro technology, and the result was as expected in the experiment.

Management of boilers often depends on human hands. Steam pressure and combustion gas management These are integrated with water level management. If the water level is abnormally lowered and left unattended, the boiler may become empty. The flat reflection type water level meter 6 installed in the past is an important part that can be seen with eyes when something goes wrong with the boiler. Yes. If an optical sensor is attached to the flat reflection type water level meter 6 and the water level is detected without contact, it can be used as a highly reliable device, so that inspection and maintenance are not required frequently.

Is a conventional float type water level detector Is a conventional electrode-type water level detector (A) shows the whole schematic diagram of a furnace flue tube boiler. (B) shows a cross-sectional view (A) is a front view of a flat reflection type water level gauge, (b) is a side view. (A) is a sectional view of a water level meter prism, (b) is a diagram of the reflection optical action of an optical sensor attached to the water level meter. Is the specifications and data chart of the optical sensor Is 5 optical sensors attached to the reflective water level gauge Is a control unit for water level control

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows that a conventional water level control device always manages the water level using a float type water level detector. The float type has a limit switch on the opposite side through a fulcrum, and the limit switch is mechanically turned on and off depending on the water level. The structure is simple, and it is a mechanism that receives this signal and issues a water supply command from the control panel to the solenoid valve.

FIG. 2 shows a conventional electrode type water level detector. The electrode type has four electrodes and a mechanism for turning a relay ON and OFF by passing a weak current in water. It must be periodically disassembled and replaced. If there is an abnormality in the water supply route, a low water level alarm will notify you, but this is also electrode type. The electrode type has the disadvantage that if the water in the water column tube does not circulate, the condensed water gradually approaches pure water and does not conduct electricity.

FIG. 3A is an overall schematic view of the furnace tube smoke boiler body 12. (B) is sectional drawing, the upper piping of the flat reflection type water level gauge 6 is connected to the main steam pipe 8, and the lower part is connected to the water storage part 11 of the boiler body tank. The water level of the boiler body tank 12 and the water level of the water level gauge are always at the same level. FIG. 3 (b) shows the water level difference between the safety low water surface 17 and the smoke pipe (flame) 18. The furnace smoke tube boiler has a water level difference of 75 mm so that the smoke tube is not exposed on the water surface. Depending on the type of boiler, it may be 100 mm. This is the safe low water surface setting position. The boiler engineer determines whether the float-type or electrode-type water level detector is operating correctly while looking at the water level gauge, but it takes time to determine whether it is abnormal. In the present invention, since the optical sensor monitors the water level meter in place of human visual observation, information is transmitted to the control panel in real time if there is a problem.

4A is a front view of the flat reflection type water level gauge 6, and FIG. 4B is a side view thereof. FIG. 5A is a cross-sectional perspective view of the prism glass 19 which is a component constituting a flat reflection type water level gauge. FIG.5 (b) is side surface sectional drawing of a water level meter, and the optical sensor is attached. FIG. 6 shows a product name, specification and data of an example of a suitable optical sensor.

The prism glass 19 shown in FIG. 5A is a transparent glass, and has a structure in which V-shaped grooves 20 are formed in four rows in the vertical direction. This portion is in contact with water on the back surface of the glass, that is, the surface on which the V-shaped groove 20 is formed, and is fixed in pressure contact with the water tank with screws using an iron plate and a gasket. The front surface is smooth with respect to the back surface V shape so that it can be seen by humans.

FIG. 5B shows a state where the optical sensor of the water level meter emits light and is reflected. If there is water, the light is refracted by the prism, passes through the water and becomes non-reflective. The flat reflection type water level meter 6 uses the optical action to diffusely shine white when light enters when there is no water, and to refract the light by the prism when light enters when there is water. It is a thing. An optical sensor was attached here to emit light, and reflected light was received. Using this physical optical action, the electrical circuit was opened and closed without contact, and signals were taken out. The optical sensor reacts only with a special color, and preferably a color mark sensor. As an example, the manufacturer is manufactured by Keyence, and the product number and data are shown in FIG. This product emits green light, and the sensitivity for each color is shown in the band graph. As shown in the graph, since the light receiving sensitivity of the green reflected light is high, it is easy to distinguish between the case where the emitted light is reflected by the prism and the case where it passes through the prism, and the presence or absence of water can be detected with high sensitivity.

Returning to FIG. 5, a contactless optical sensor having a high water level 1, a normal water level 2, and a safe low water level 3 is attached to the flat reflection type water level gauge 6. Since there is no contact, there is little mechanical wear and deterioration over time. When the water level of the boiler main body tank 12 (see FIG. 3) is lowered, the water level of the flat reflection type water level gauge 6 connected by piping is also lowered. Then, the service level sensor 2 attached to the flat reflection type water level gauge 6 is turned on. In response to the signal sent to the control panel, the water supply solenoid valve 9 is turned ON, water is supplied to the boiler body tank 12, and the water level of the boiler body tank 12 rises. Then, the water level of the flat reflection type water level gauge 6 also rises. When the water level reaches the high water level sensor 1, the water supply solenoid valve is closed by the signal sent to the control panel and the water supply stops. Thus, the water level is kept constant.

For example, assume that an abnormality has occurred in a part of the water supply circuit due to a mechanical failure. Assume that the solenoid valve is broken and cannot supply water. The water level continues to fall and finally the water level drops to the safe low water level sensor 3. Since there is a safe low water level sensor 3 for this time, an abnormality is detected. The abnormality signal is immediately sent to the control panel, and the burner oil supply valve is closed by a command from the control panel. At the same time, an alarm is notified to the operator. After that, the operation of the boiler is programmed to stop safely by the control sequence.

Here, let's consider the worst case of what happens if the safety low water level sensor 3 is out of order. In this case, no warning is given and the burner refueling valve is not closed, so the water level will continue to drop unless the operator notices it. In order to prevent this, an abnormally low water level sensor 5 is installed as a double safety device as shown in FIG. Thus, the safety low water level sensor 3 is backed up. The same is true for high water level sensors. Therefore, an abnormally high water level sensor 4 was installed as a backup for the high water level sensor. In either case, an alarm is notified to the operator and an abnormal signal is transmitted to the control panel. The boiler control panel receives the signal and safely stops the operation of the boiler by the control sequence.

FIG. 8 shows a control unit 7 that performs water level control. All five sensors 1 to 5 are wired to the control unit 7. The control unit 7 is provided with a control circuit (not shown), and performs feedback control based on the detection signals of the sensors 1 to 5. The control signals are, for example, a water supply valve opening / closing signal and an alarm signal, and are sent to a boiler control panel (not shown).

DESCRIPTION OF SYMBOLS 1 High water level sensor 2 Common water level sensor 3 Safety low water level sensor 4 Abnormal high water level sensor 5 Abnormal low water level sensor 6 Flat reflection type water level gauge 7 Control part 8 Water level control device Boiler main steam pipe 9 Water supply solenoid valve 10 In boiler tank Steam chamber 11 Reservoir in boiler tank 12 Furnace flue tube boiler body shell 13 Furnace flue boiler body flue 14 Burner 15 Limit switch 16 Float 17 Boiler safety low water surface 18 Boiler flue surface 19 Water surface level prism forming glass 20 Prism formation Longitudinal groove 21 of shape Water level gauge steam chamber part 22 Water level gauge water chamber part

Claims (5)

A water level detection device for detecting the water level of a boiler main body tank used in a boiler, a flat reflective water level meter made of glass having a prism-shaped unevenness on the back surface in contact with water, and the flat reflective water surface And an optical sensor that detects the water level by irradiating light from the front side and detecting the reflected light . Is a water level detection device. 2. The water level detection device according to claim 1, wherein the optical sensor is a color mark optical sensor that emits light of a specific color and has different sensitivity to reflected light depending on the color of the reflected light. The said optical sensor is a water level detection apparatus of Claim 1 or 2 which detects the upper and lower limits of the range which should maintain a water level, and three water levels of a safe low water level. The water level detection device according to claim 3, wherein the optical sensor detects a water level higher than the upper limit and a water level lower than the safe low water level. A water level control apparatus comprising: the water level detection apparatus according to claim 1; and a control circuit that controls a water level based on a result detected by the optical sensor.

Images