Hotpot accessories and safety technical requiremen

2022-10-03
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Boiler accessories and safety technical requirements - water level gauge (III)

water level gauge is used to indicate the water level in the boiler and monitor the dynamics in the boiler, so as to control the water level in the boiler within the normal range. When the boiler is running, adjust the water supply according to the water level indicated by the water level gauge to meet the needs of steam load changes, and the smaller the fluctuation of water level, the better. Too high or too low water level in the boiler is not allowed. If the water level is too high, it is easy to increase the water content in the steam, reduce the quality of the steam, and even cause water hammer and damage to the pipeline system. The more water content in the steam, the more impurities and salts in the water in the boiler will be brought out with the steam by using the steam, which will degrade the performance of the equipment and machines, and even cause failures. If the water level is too low, it is easy to cause damage to the water cycle. In case of serious water shortage, it will also cause overheating, deformation and damage of boiler tubes or drums, and even cause boiler explosion accidents

water level gauge failure or operator error will cause serious water shortage, boiler explosion or serious damage to boiler equipment and other major accidents. Therefore, every stoker and boiler equipment management personnel must pay enough attention to this, strictly monitor the water level and maintain the normal water level to ensure the safe operation of the boiler. Each boiler must be equipped with the necessary number of sensitive and reliable water level gauges according to the regulations. The operation of boilers without water level gauge or with water level gauge failure shall be absolutely prohibited

1. principle and structure of water level gauge

the water level gauge is made by using the principle of connector. The water connecting pipe and steam connecting pipe of the water level gauge are connected with the water space and steam space of the furnace respectively. The water level gauge and the boiler form a connector, and the water level displayed by the water level gauge is the water level in the drum. There are two kinds of water level gauges commonly used on boilers: glass tube and glass plate

(1) glass tube water level gauge: this water level gauge is composed of steam cock, water cock, drain cock and glass tube. The glass tube is composed of heat-resistant glass, with a diameter of 20mm generally and 15mm individually. The glass tube water level gauge is simple in structure and low in cost. It is widely used in low-pressure small boilers. However, the glass tube water level gauge is often broken due to improper installation of glass, uneven stress, sudden temperature change and other reasons. In addition, the glass tube has poor pressure resistance, which is easy to leak air and water at the padding, resulting in inaccurate water level and other defects. Therefore, this kind of water level gauge is used on boilers with nominal pressure not exceeding 1.57mpa, and most of them are used on boilers below 0.78mpa. In order to prevent the glass tube from breaking, steam or water from hurting people, glass 4. After the hardness tester is adjusted, the glass tube is usually equipped with safety protection devices. At present, the commonly used safety protection devices include cylindrical protective covers made of thin iron plates and glass protective covers on three or four sides. The iron plate protective cover should have enough clearance to observe the water level and ensure lighting. The glass of the glass protective cover must be tempered glass. Do not use ordinary glass to avoid accidents

(2) glass plate water level gauge: its structure is similar to that of glass tube water level gauge, but the glass is replaced by flat glass plate. This kind of water level gauge can be divided into double-sided glass water level gauge and single-sided glass water level gauge according to its characteristics

double sided glass water level gauge, also known as perspective glass plate water level gauge or perspective water level gauge. The ordinary perspective water level gauge consists of two flat glasses of the water level gauge. Many customers bought the space of the electronic universal experimental machine, which is connected with the interior of the pot through steam and water connecting pipes. There are several reflection grooves with triangular cross-section inside the glass, and the light is emitted from the rear of the water level gauge through the two glasses. Due to the prism phenomenon of the reflection ditch, the light reflected from the water part shows ink stripes, while the reflection ditch of the steam part shows bright white. The structure of the two-color water level gauge is similar to that of the ordinary glass plate water level gauge, and the light is also transmitted. The difference is that the water level gauge body in the middle is inclined to a certain angle, and the rear lighting is composed of two rows of vertically arranged bulbs (or lights). When the stoker looks over the steam space, he sees that the red light bulb in the left row is in good condition after the test run, so the steam part is red; From the boiler water below, due to the refraction phenomenon of light passing through different refractive index parts, resulting in offset, we can see the green light bubble in the right row of Germany, so the boiler water part is green. What you can see with this water gauge is "steam red and water green", which is certainly clearer than other water gauges. However, the use of two-color water level gauge also has the defects of small observation angle and inability to observe with the help of flashlight during power failure, so it is not suitable to use it all on the boiler

single sided glass plate water level gauge, also known as reflective water level gauge. This kind of water level gauge is inlaid with a flat glass in front of the steel shell, and the inner surface of the flat glass is carved with several triangular prismatic grooves. Because the light source is in front, and the light is reflected through the groove of the steam part of the water level gauge, the steam part is silver, while the water storage part of the water level gauge is dark brown, so that the water level can be clearly displayed

2. Safety technical requirements

each boiler shall be equipped with at least two independent water level gauges. The water level gauge here refers to the glass water level gauge. Although some boilers are equipped with various automatic water feeding and water level automatic detection instruments to strengthen the control of water level, they cannot replace the glass water level gauge

the water level gauge is installed in a place convenient for observation and has sufficient lighting. If lighting is installed next to the water level gauge, the power supply with safe voltage should be used

the water level gauge shall have obvious signs indicating the highest and lowest safe water levels. The lowest visible edge of the glass plate (tube) of the water level gauge shall be 25mm lower than the minimum safe water level, and its highest edge shall be 25mm higher than the maximum safe water level

the water level gauge should have a drain cock (or drain valve) and a drain pipe connected to a safe place. The drain cock and drain pipe are used to purge the water level gauge

the structure and device of the water level gauge should meet the following requirements: when the boiler is running, it can purge and replace the glass plate (tube). When two glass plates are staggered up and down to form a water level gauge, it can continuously indicate the water level. The inner diameter of the steam water connecting pipe between the water level gauge (or water gauge column) and the drum shall not be less than 18mm. When the connecting pipe length is greater than 50mm or there is bending, the inner diameter should be appropriately enlarged to ensure that the water level gauge is sensitive and accurate. The connecting pipe should be as short as possible, the steam connecting pipe should be able to automatically drain water with the water level gauge, and the water connecting pipe should be able to automatically drain water to the drum. The steam and water connecting pipes shall be arranged horizontally. When a water meter is installed between the water level gauge and the drum, attention shall be paid to ensure that the drum steam connecting pipe of the water meter column is not lower than the highest visible edge of the water level. The water connecting pipe between the water meter column and the drum shall not be higher than the lowest visible edge of the water level gauge. The inner diameter of each cock on the water level gauge and the inner diameter of the glass tube shall not be less than 8 mm. If the inner diameter is too thin, it is easy to block and destroy the equal height of water level on both sides of the connector. The error between the water level in the glass tube and the water level in the drum is too large due to the capillary effect. If a valve is installed on the water level gauge (or water gauge column) and the steam and water connecting pipe of the drum, the valve must be fully opened during normal operation, and the handwheel of the valve must be removed and kept properly to avoid misoperation

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