1. Electronic automatic normal temperature drying technology and its products
Electronic automatic normal temperature drying technology is a new type of moisture-proof, mildew-proof and oxidation-proof drying technology developed in recent years under the background of modern technology. Protective technology. Due to the use of normal temperature suction dehumidification, there are no defects of the traditional refrigeration type. The dehumidification efficiency is not affected by the ambient temperature. It can dehumidify efficiently all year round. Even in winter, the humidity in the box can be reduced to below 30% while dehumidifying. , it also has the outstanding advantage of purifying harmful industrial waste gas in the controlled space. Not only does it meet the requirements of being moisture-proof, mildew-proof and oxidation-proof, it is also of great significance for preserving imaging films and magnetic recording materials. Its representative product is a suction-type electronic automatic moisture-proof box. It has become the mainstream product of commercially available electronic automatic moisture-proof boxes.
Normal temperature drying technology was studied in the mid-to-late 1980s, and early products appeared. Since then, normal temperature drying technology has focused on intelligent control, automatic dehumidification, as well as the improvement of dehumidification speed and control display accuracy. Improvement aspects are continuously developed and strengthened. In 1993, the CARTEMAN brand electronic automatic moisture-proof box with China's independent intellectual property rights was launched with patent authorization from the National Patent Office of China. The invention of its fully electronic intelligent dynamic high-speed dehumidification electronic automatic moisture-proof box technology has raised room temperature drying technology to a whole new level. Until 2002, the electronic automatic normal temperature drying technology used in CARTEMAN brand electronic automatic moisture-proof box products has been authorized by 4 national invention and utility model patents. CARTEMAN brand products have become the leader in the international advanced level of electronic automatic normal temperature drying technology. Electronic automatic normal temperature drying technology has outstanding advantages and is widely welcomed because it solves the shortcomings of traditional dehumidification, mildew prevention, and oxidation corrosion prevention methods. The electronic automatic moisture-proof boxes currently sold in the Chinese mainland market, in addition to CARTEMAN brand products, mainly include "Wandefu" brand static osmotic dehumidification products produced by Zhuhai under the authorization of CARTEMAN
and Certain brands of static osmotic dehumidification products produced in mainland China use Taiwanese trademarks.
2. Types and differences of electronic automatic moisture-proof boxes (drying boxes)
The standard suction-type automatic moisture-proof box is composed of a humidity sampling control device, a timer, a dehumidifier and a driver It consists of several parts such as device, hygrometer, chassis and so on. Due to the influence of price factors on product design and manufacturing, even standard products have many differences. In addition, there are also simplified products on the market. The differences between these are
(1) Humidity sampling and control display
Mechanical humidity sampling and control display models
This type of product is the most common Electronic automatic moisture-proof box products. It is characterized by using a mechanical humidity sensor for air sampling and a mechanical comparator to preset the humidity in the box. The suction and discharge door action mechanism is composed of a memory alloy spring, a return spring and a connecting rod. The integrated circuit timer controls the dehumidification program with a pointer. The hygrometer indicates the current humidity inside the box. The drying process is natural convection and penetration.
The mechanical humidity sensor used is mainly a length-changing humidity sensor produced in Dongguan. The principle is to stretch a nylon hydrophilic plastic film on a metal bracket. When the ambient humidity rises, the plastic film will absorb moisture and shrink like cotton, shortening and tightening. Press the button of the micro switch to turn on the power, making it moisture-proof. box work. When the humidity drops, the plastic film will stretch and relax. Release the button of the micro switch to cut off the power, causing the moisture-proof box to stop working. By rotating the control knob, an eccentric wheel is driven to adjust the position of the plastic film pressing the microswitch, that is, the reference pressure, so that when the control knob rotates to a position representing a certain humidity range, it can be turned on or off. power supply to achieve the purpose of controlling the humidity in the box. Since this kind of mechanical humidity sensor must absorb water or naturally evaporate to a certain extent before it can generate the necessary force to activate or release the micro switch, the response is slow and the lag time can even be as long as ten or twenty minutes. It cannot Respond to changes in humidity in a timely manner.
It cannot react to changes in trace amounts of water, and the plastic film is greatly affected by the environment, and the annual drift value of the control point is large. Therefore, the electronic automatic moisture-proof box using this humidity sensor has an error of more than ±10, so it is classified as "high, medium, and "Low" or "L, H" (i.e. low, high) indicates the humidity inside the box, rather than marking the specific humidity value. In addition, due to the instability of the plastic film material itself, it is easy to age and deteriorate, affecting its lifespan. Since the price of this sensor is only 20 to 30 yuan, which is very low, it is widely used, including CARTEMAN's mass-level products, all Zhuhai Wonderful products, and most products of Japanese and Taiwanese brands.
Since this kind of mechanical humidity sensor has no humidity electrical signal output and cannot realize digital display, most of them are equipped with a mechanical pointer hygrometer to display the humidity in the box.
The humidity sensors of mechanical pointer hygrometers are either hair-type or made of polymer hydrophilic plastic material coated on a metal hairspring. Its principle is the same as that of the mechanical humidity sensor, which is a length-changing type. The displacement generated by the length change is used to drive the pointer shaft, so that the pointer moves on the dial, thereby realizing the humidity measurement function. Therefore, it has the same weaknesses as mechanical humidity sensors, that is, slow response, long lag time that can be as long as ten or twenty minutes, inability to react to changes in trace amounts of water, and large display errors, generally above ±7, and as high as ±10 Above, the annual drift value is large, unstable, and prone to aging and deterioration, affecting the service life. Although it cannot measure accurately and reliably, and the displayed value can only be used as a reference, it is widely used because it is cheap and can work without an electrical signal.
There are also some products that use mechanical humidity sensors and use separate LCD digital hygrometers. However, since this kind of electronic automatic moisture-proof box is a low-end product, it is limited by market price. A low-end LCD digital hygrometer for observing home weather conditions.
In this type of electronic automatic moisture-proof box, since the sampling control and display are independent and unrelated to each other, there is a cumulative error, and the total error of the random sampling control display can be as high as ±20 or more.
Electronic humidity sampling and control display model
The electronic humidity sensor can capture trace changes in air humidity and is responsive, with a lag time of only a few seconds and good linearity. , the error is small and the annual drift is small. Because it can
convert changes in air humidity into electrical signal output, digital display is realized. Since the control and display signals come from the same source, the cumulative error caused by the separation of sampling control and display is avoided. Therefore, the total error of the sampling control display is the linear error of the electronic humidity sensor itself, and This linear error can also be adjusted through a compensation circuit to further improve accuracy.
Measurement-grade electronic humidity sensors with an error of ±3 and good stability, such as products from Finland, cost about 1,500 yuan/piece. If adopted, electronic automatic humidity sensors will be greatly improved
The price of the tide box, so ordinary instrument-grade electronic humidity sensors with an error of ±5 have become the first choice. For example, CARTEMAN electronic automatic moisture-proof box uses Japanese famous brand products, which have good stability and error indicators that can fully meet the usage requirements.
At present, there are a small number of domestic units producing electronic humidity sensors, but the quality is inferior and the price is high. In particular, the stability index cannot meet the requirements of long-term uninterrupted use of moisture-proof boxes.
Moisture-proof boxes that use electronic humidity sensors generally use high-quality secondary precision voltage regulators to power the entire machine, and the voltage adaptability range is wide.
Although the cost and selling price of electronic humidity sampling and control display moisture-proof boxes are higher than those of mechanical humidity sampling and control display products, from 10 to 20 years old
From the perspective of long-term effective and safe storage, as well as the quality and longevity of the product, it is still the focus of selection, and it is also the development direction of electronic automatic moisture-proof boxes.
Mechatronic humidity sampling and control display model This type of product is a patented new humidity sampling and control display method invented by CARTEMAN in 2002. The characteristic is that due to the integrated patented structure of optical, mechanical and electrical combination, there is no cumulative error. The total error of its control display is the display error of ±7 of the mechanical pointer hygrometer itself. Although the problems such as lag and drift of mechanical products still exist, the accuracy is greatly improved, making it close to electronic humidity sampling and The model has a control display and maintains a low price. Therefore, compared with the models using mechanical humidity sampling and control display, the performance is greatly improved and the price is basically the same, so it has outstanding advantages. It has been adopted in CARTEMAN household-grade automatic moisture-proof boxes and put on the market.
(2) Dehumidification type
Static penetration dehumidification and dynamic high-speed dehumidification models
The dehumidification speed of the electronic automatic moisture-proof box is divided into static according to the structure. There are two types of osmotic dehumidification and dynamic high-speed dehumidification.
The dry gas produced in the dryer (i.e. dehumidifier core) of the static dehumidification model is replaced by the moisture existing in the box through static natural exchange and penetration to complete the dehumidification process.
As a result, the dehumidification speed is very slow. Especially for the first use, it usually requires more than 24-48 hours of pre-operation. Therefore, the application range of this type of machine is limited. In fact, it is more suitable for storing items that do not contain moisture, such as lenses and camera bodies, and for users who do not frequently pick up and place items. For professional users who are in a high-humidity environment and frequently open the door several times a day to pick up and place items, the humidity may never drop. If it is used to store items with high moisture content, such as film, photographic films, photos, audio and video tapes, computer disks, stamps and other paper products, the dehumidification time will be particularly long. If the amount of storage is large, the dehumidification time can even last for more than half a month, and the machine may even be kept running continuously, shortening the life of the machine. Moreover, when the humidity in the box drops, once the door is opened to take out items, the humidity rises rapidly and takes a long time to drop. Most of the products currently on the market are static osmosis dehumidification models.
The dynamic high-speed dehumidification model dehumidifies about 8-10 times faster than the static penetration dehumidification model under the same conditions. Due to the extremely fast dehumidification speed, it meets the requirements of frequently opening the door to access items in high-humidity environments. It is suitable for the use requirements of professional users, and is suitable for storing large amounts of films, photographic films, photos, audio and video tapes, computer disks, stamp paper products and other items with high moisture content, and can achieve rapid and deep dehumidification, which is very important for storing powder materials and storage environment. Essential for users with particularly low humidity requirements.
It should be pointed out that the so-called "low humidity" products launched by some manufacturers actually install multiple static osmotic dehumidification movements in a box, which has limited improvement but increases the probability of failure and power consumption. , the size of the movement also takes up the effective storage space that users spend money to purchase.
(3) Mechanical drive mode of the moisture exhaust door
Memory alloy spring driven and micromotor driven models
Moisture suction and exhaust door of the electronic automatic moisture-proof box There are two main methods of switching movement: memory alloy spring drive and micromotor drive.
Products driven by memory alloy springs use the principle that the memory alloy spring can expand and contract due to temperature changes to produce a stroke, and form a moisture suction and discharge door action mechanism with a return spring and a connecting rod. Although memory alloy materials have been around for one or two decades, their research and understanding by the scientific community is still far from sufficient. Although it is known that temperature changes can cause the steel crystal phase to produce a certain memory effect during the mutual transformation of martensite and austenite, the principle and mechanism are still not clear, and many links cannot be repeated using scientific methods. Sexual reappearance, there are still many unsolved mysteries. Therefore, memory alloy materials are currently only in the preliminary application stage, and there are no national or international standards for memory alloys in countries around the world.
At the current level of technology, the working characteristics of memory alloy materials are greatly affected by time and the working environment. As a power source for driving moisture suction and discharge doors, the reliability is not very high. The most likely failure is that the memory alloy spring fails after being used for a period of time. The electronic automatic moisture-proof box cannot dehumidify normally due to the inability to move or insufficient movement stroke. However, the use of memory alloy springs, because of its very low price, not only greatly simplifies the product structure, but also greatly reduces the cost. It is precisely because of the use of memory alloy springs that low-priced low-end products of electronic automatic moisture-proof boxes can be produced, making Low-income individual users can use electronic automatic moisture-proof boxes as soon as possible, and manufacturers generally extend the service life of their products by extending the warranty period (note: not a failure-free period).
For products driven by motors, the opening and closing movement of the moisture suction and exhaust door only takes a few seconds, while the dehumidification work program of the electronic automatic moisture-proof box only requires a few seconds of opening and closing movement of the moisture suction and exhaust door in a day. times, so the total rotation time of the motor is less than one minute a day and less than 6 hours a year, and the life of the motor itself can last for several years. Therefore, the use of motor-driven electronic automatic moisture-proof box products has high reliability and long life. Since the production cost is much higher than that of products driven by memory alloy springs, the product price is also higher. However, for units and professional users who pursue high reliability, such products are still the first choice.
It should be pointed out that some products do not use electronic timers, but use a low-speed motor that takes several hours to rotate once to drive two cams to form a mechanical timer to drive the timing action of the moisture suction and discharge door. Since the low-speed motor runs 24 hours a day, the reduction gear quickly wears and causes excessive clearance, resulting in mechanical noise that "clicks" all day long. The noise problem cannot be ignored. This type of product has no electronic components and is actually a mechanical product. It has basically withdrawn from the market.
(4) Simple visual identification method of electronic automatic moisture-proof box (drying box) products
Electronic automatic moisture-proof boxes with different types of structures have their own characteristics in appearance, carefully It is not difficult to identify by observation.
1). How to identify suction and semiconductor refrigeration models. Observe the rear of the box. If there is a large aluminum plate, or a radiator made of aluminum profiles, or a heat dissipation fan , or have foam plastics or textiles used to absorb water, but do not have the moisture drainage valve unique to suction products, they are semiconductor refrigeration models. On the contrary, it is a suction model. It is not difficult to identify if you observe carefully.
2) Identification methods of mechanical and electronic humidity sampling control display meter, but the hygrometer is independent and has no cable to connect to the circuit controller in the box. The control points on the humidity setting controller are marked "high, medium, low" or "H, M, L". Plug in the power and turn the humidity Check the controller knob and listen carefully for a "click" sound of the power switch operating at a certain position. If the metal frame of the mechanical humidity sensor can be seen through the ventilation hole, it is a mechanical product.
When a light-emitting digital hygrometer is used, and the hygrometer is connected to the circuit controller in the box by a cable, the control point on the humidity setting controller may indicate specific control values ??such as 30, 40, 50, etc., or there may be The increase/decrease indication button, if you press and hold it, the numbers in the display window will increase/decrease, which is an electronic product. The luminous digital meter of some products is a thermometer rather than a hygrometer, so you should pay attention to identify it.
If a circular mechanical pointer hygrometer is used, but there is a cable on the hygrometer connected to the circuit controller in the box, it is an electromechanical integrated humidity sampling control display. Currently, only CARTEMAN has such products.
3), identification method of memory alloy spring drive and motor drive
First confirm that the ambient humidity in the box is higher than the set control value, and then find the moisture drainage valve and observe it. When it is in the closed state and there is no power, use your fingers or small pieces of wood to gently push the moisture drain door to open it. When you let go, the door will automatically bounce back and close; you can also unplug the power plug when the moisture drainage door is closed and plug it back in to see if it is powered on. The moisture drainage door opens slowly and takes several minutes to fully open. It is a memory alloy spring-driven product. Products that require a lot of force to open the drain door or that open the drain door within a few seconds after being powered on are motor-driven products.