Zhengzhou Gou's medium frequency induction furnace manufacturer explains the knowledge about heating tubes

For many customers and even many of our salesmen who work on heating tubes, sometimes they often cannot distinguish between the working voltage and the rated voltage of the heating tube. Customers who cannot distinguish between the working voltage and the rated voltage will often encounter the following problems when they return to use: the heating tube does not generate heat, or the heating temperature of the heating tube is too high, and the heating tube is broken. These two extreme problems are caused by incorrect voltage connection.

Working voltage of electric heating tube: Regarding the working voltage of electric heating tube, we will introduce it to you in two ways.

1. A single branch is connected to the power supply. For a single electric heating pipe connected to the power supply, the working voltage of the electric heating pipe refers to the voltage connected to the component specified at the time of design, that is, the rated voltage. In this case, a single heating tube usually works, such as a single-head electric heating tube, a U-shaped heating tube, etc.

2. Multiple power supplies connected in series. For multiple electric heating tubes or a group of electric heating tubes connected in series to the power supply, the working voltage of the electric heating tube refers to the voltage connected to this group of electric heating tubes specified at the time of design. This situation may occur on flange heating pipes.

Note: This involves the issue of whether multiple electric heating tubes are connected in series or in parallel. Therefore, when our salesmen communicate with customers to ask about the voltage, if multiple electric heating tubes need to be connected, we need to ask the customer whether they are connected in series or in parallel, so that we can determine the voltage of a single electric heating tube.

Rated voltage of electric heating tube:

The rated voltage of the electric heating tube refers to the voltage connected to the electric heating tube that is specified during redesign and marked on the electric heating tube shell. Or in other words, the rated voltage is the voltage given by the customer when we require us to process and produce it. Generally there are 24V, 48V, 110V, 220V, 380V and so on.

After reviewing the concepts, let’s take a look at why the two limit states we told you before appear. First of all, our heating tube salesmen all know that the resistance value of our heating tubes is fixed. Different power supplies will produce different powers, and different powers will produce different amounts of heat. The reason why the above two extreme phenomena occur is that they are connected to different power supplies. With a given resistance, if it is connected to low voltage, the power will tend to be small, so the stainless steel electric heating tube will generate almost no heat; if it is connected to high voltage, the power will tend to be large, so the heating tube power will be too high, causing the heating tube power to exceed the standard. , then the stainless steel heating tube will be too high due to the internal temperature of the heating tube, so that the resistance wire inside the heating tube will fuse and the heating tube will be scrapped.

How to use single-head electric heating tube and extend its life

According to national standards, electric heating tubes can generally be replaced with new ones after 6 months. In terms of national security, 6 months is the safest life cycle. In fact, this is not the case. According to our work experience, single-head electric heating tubes can be replaced as long as they are used properly. , the life span can be more than 1 year or even longer. This life span is closely related to the working environment of the single-head electric heating tube. The quality of single-head electric heating tubes mainly depends on the following aspects: electrical strength, insulation, leakage current, power accuracy, lifespan, corrosion resistance, size, etc. The main factor that affects the insulation of single-head electric heating tubes is the sealing process of single-head electric heating tubes. Generally, Huhui can achieve more than 1000 megohms. The factors that affect the electrical strength of a single-head electric heating tube mainly include the thickness of the insulation layer, the quality of the raw materials of the insulation layer, the length of the single-head electric heating tube, the bending radius and the number of bends. The cold withstand voltage of a single-head electric heating tube can generally be 2000V, 1 second, and the breakdown current is 0.5mA. It is mainly related to the quality of the resistance wire and the process level of the manufacturer. Before mass production, temperature coefficient testing is required to determine the cold resistance in the qualified power range. It is mainly related to the temperature when the single-head electric heating tube is used, the voltage used by the single-head electric heating tube, the heating length of the single-head electric heating tube, etc. An important assessment indicator for high-temperature single-head electric heating pipes. Common problems encountered by water heating single-head electric heating tubes and barbecue single-head electric heating tubes. In addition to the reasonable selection of materials, it is also related to the heat treatment of the single-head electric heating tube, the surface condition of the single-head electric heating tube, etc. The service life of a single-head electric heating tube is not only related to the quality of the electric heating wire, but also related to the quality of the magnesium oxide powder, the selection of the diameter of the electric heating wire and other factors. For high-temperature single-head electric heating pipes, the surface load of single-head electric heating pipes can be manufactured below 8W/CM2. When selecting the diameter of the heating wire, it is necessary to calculate the surface load of the heating wire to meet the life requirements. Single-head electric heating tubes are electrical components that specialize in converting electrical energy into heat energy. Because they are cheap, easy to use, and pollution-free, they are widely used in various heating situations. The service life of single-head electric heating tubes is very long. The general design service life is more than 10,000 hours, which is equivalent to 5 heating seasons. If you pay attention to maintenance work, your service life can be further extended.

1. The input power supply voltage of the single-head electric heating tube should not exceed 10% of the rated voltage marked on the various single-head electric heating tubes. If the voltage is lower than the rated voltage, the heat generated by the single-head electric heating tube will also decrease. .

2. For the terminal of the single-head electric heating pipe, two nuts should be tightened relative to each other during wiring. Do not use excessive force to avoid loosening the screws and damaging the single-head electric heating pipe.

3. The heating part of the single-head electric heating tube should be completely immersed in the heating medium to prevent the heat from dissipating quickly and exceeding the allowable heating temperature, causing damage to the electric heating tube. In addition, the lead-out part of the wiring should be exposed on the insulation layer of the heater or outside the heater, so that this part should not be damaged by overheating.

4. When selecting a single-head electric heating tube, special attention should be paid to the heating medium. There should be no erosion of the single-head electric heating tube shell material.

5. If the single-head electric heating tube is used for a long time, if thick pipe dirt and grease accumulate on the surface, it should be removed regularly. Otherwise, the heat transfer performance of the single-head electric heating tube will be reduced and the heat load on the surface of the tube will exceed the rated allowable and be damaged.

6. The single-head electric heating tube should be stored in a dry warehouse. If the surface becomes damp due to long-term storage, use a megohmmeter to measure the insulation resistance. If it is less than 1 megohm/500 volts, the heating tube should be placed in a drying oven at 200 degrees for drying.

7. When heating certain viscose and other substances, such as sodium nitrate, stearic acid, paraffin, etc., the power supply voltage should be lowered when heating is started to reduce the calorific value of the single-head electric heating tube. When it is completely melted into a liquid, increase the voltage again. to the rated voltage for heating. In fact, the life span of a single-head electric heating tube really depends on the initial design of the single-head electric heating tube, the selection of internal materials of the single-head electric heating tube, and the selection of external materials. Determining the working environment of the single-head electric heating tube and correctly selecting the various materials of the single-head electric heating tube are crucial to the true service life of the single-head electric heating tube.

Points to note when dry heating heating tubes

Depending on the working environment, heating tubes are generally divided into dry-burning heating tubes and liquid heating tubes. We have introduced dry-burning heating tubes to you before - "Analysis of air dry-burning heating characteristics" It is not difficult to see from the characteristics of dry-burning heating tubes Yes, there are many things that need to be paid attention to when using dry heating tubes. Although dry-heating heating tubes are used for dry heating, they need to be paid attention to as much as liquid heating electric heating tubes (Extension: Why do immersed heating tubes break when they are separated from the liquid?). First of all, for dry-fired heating tubes, we must first consider the material: ordinary carbon steel and stainless steel 304 are generally used. The heating effects of these two materials are similar, but the difference between ordinary carbon steel and stainless steel 304 is that ordinary carbon steel will rust once it is not used for a long time. Once the heating tube rusts, the heating tube can no longer be used. Therefore, relatively speaking, it is more cost-effective to choose stainless steel 304. For experimental dry-fired heating tubes, ordinary carbon steel can be used. Secondly, for dry-fired heating tubes, what we must consider is the temperature. The reason why the service life of dry-fired heating tubes is generally not high is because the temperature is not well controlled, resulting in the internal temperature of the heating tube being too high, resulting in breakdown of the heating tube or even tube explosion. (Expansion: Reasons why heating tubes burst) Generally, dry-burning heating tubes have working temperatures controlled between 200-300 degrees. The last one is the special dry-fired heating tube, which is the most commonly used mold single-head heating tube among single-head heating tubes.