The Soybean Vertical Seed Conditioner is the key equipment of the soybean press plant. The good use and maintenance of the vertical seed conditioner is related to the operation effect of the whole pretreatment such as soybean peeling, crushing and rolling, and even affects the infiltration of extracting and the desolvation of wet meal. The steam consumption of the conditioner accounts for about 30% of the whole soybean processing, and the effective heating also affects the power consumption of the whole pretreatment. Good equipment condition is a prerequisite for safe, stable and efficient operation of a processing plant. In some domestic plants, the conditioner are not well maintained during long-term use, resulting in body/vent pipe leakage, heat exchange tube leakage, tube sheet leakage, unloading rotary valve failure, the feeding mechanism is not smooth, the transmission chain is broken, etc. If it is not repaired in time or maintained improperly, it will lead to equipment failure, rising cost and even safety risks.
1、Structure Composition Of The Vertical Seed Conditioner
The conditioner is a vertical tower structure. It is used for the conditioning of oil and grains. It was introduced into China at the end of the last century for temperature and moisture adjustment before soybean peeling. The conditioner is mainly composed of a feeding section, a multi-layer heating layer, an air inlet layer, an air extraction layer and a discharging section. The working principle is that the material enters the conditioner from the feeding section at the top, and flows to the multi-layer heating layer from top to bottom by the self-weight of the material. There are several groups of elliptical tubes distributed in the heating layer to heat the material flowing down by itself. The temperature of the material is automatically controlled by the temperature sensor at the outlet and the steam given control valve, which is used for the temperature control of the material. The air inlet layer is to pass the hot air heated by the air heat exchanger into the tower layer and heat the soybean with the heating layer for convection drying. The air outlet layer is to extract the moisture from the soybean through the steam outlet pipe by the centrifugal fan, and adjust the air volume through the temperature and humidity meter at the air outlet to achieve the purpose of regulating the moisture. Continuous level meter and variable frequency PID interlock control of discharge unloader are used in the feeding layer to accurately control the discharge volume. After multi-layer heating and drying, the materials are conditioned, discharged by the unloader, and enter the next process (taking soybean as an example).
2 Common Problems In The Use Of The Vertical Seed Conditioner
During the long-term use of the conditioner, due to the long-term exposure to high-temperature steam, material scouring, mechanical wear, and lack of lubrication, there will be steam, water vapor, leakage of raw beans, accumulation in the conditioner, and poor conditioning effect, etc. The emergence of a series of problems requires targeted solutions to the problems of the conditioner in the process of daily maintenance and maintenance to ensure the stable and reliable operation of the equipment.
2.1 The Conditioner steam leakage
This kind of fault is relatively common. ①.Local air leakage is mostly caused by the aging of the cover plate or the gasket of the steam inlet and outlet pipes due to long-term use, and the loose connection bolts cause steam leakage during use. It is necessary to tighten the bolts on the leakage gasket. Fix it, or replace the gasket, use a high temperature-resistant gasket, such as a tetrafluoron gasket; ②.Large-scale gas leakage of the cover plate often occurs in the process of starting and stopping, or the material is interrupted in the production process, causing the actual pressure of the steam to exceed the working pressure of the conditioner, resulting in leakage due to excessive pressure. If there is a large-scale steam leakage, first check whether the material in the tower is cut off, whether the steam pressure is within the normal range, and whether the safety valve is working normally; secondly, the leakage gasket bolts are tightened, and even partial replacement of the sealing gasket is required.
2.2 Tube Leakage Of Conditioner
Many grain and oil companies have more or less cracks in the welding of the tube head of the heating layer and cracking in the welding of the tube sheet. Such problems are relatively serious problems, which seriously affect the normal use of the conditioner. The main reason for similar problems is that the seals of the elliptical tube and tube sheet are welded and sealed by argon arc welding, and most of the materials are 304SS and seamed elliptical tubes, which are subject to high temperature steam when the equipment is used for a long time. The influence of entering and exiting fast and the low thermal conductivity of 304SS stainless steel are extremely easy to cause heat energy to not be released in time and effectively, resulting in local stress, which is likely to cause hot cracks in the tube head at the position of the tube sheet head, corrosion resistance decline and welding. Problems such as joint embrittlement.
To solve these problems, how to deal with them effectively? Firstly, through analysis, the reason is that the long-term use of high-temperature environment has resulted in the decline of the material characteristics of the nozzle. Generally, there are two kinds of maintenance measures, (1)、Partial replacement shall be carried out for the crack at the tube head of the tube row. Partial replacement shall solve 80% of the material cost than the whole replacement. Firstly, the leaking tube row of the conditioner shall be found through the online pressure test. The full root (including the weld) position of the leaking single elliptical tube row shall be ground with an angle grinder, and the tube row shall be driven out along the original pipe. Both ends of the heating tube shall be cut off by 10-15 cm according to the corrosion of the elliptical tube row, and the bevel angle shall be polished; cut the new heating pipe by 20-30cm according to the replacement length, grind the bevel and weld it with the original corroded and cracked row pipe to form a new available row pipe. Then grind the welded position of the welded row pipe into the original tube plate hole, and then weld the tube plate connection with argon arc welding, during the welding process, it shall be noted that the original hole shall not be expanded to ensure that the pipe and tube sheet are fully welded. The small gap in the original hole and low current welding shall ensure that the original tube sheet is not cracked during the welding process. If there are many leakage points, the positions of intermediate welds shall be installed alternately on both sides. (2)、For the tower layer with many leakage points at the pipe head of each layer, the whole layer of tube plate and the row of tubes can be replaced. Two tube plates can be customized and processed. The whole layer of tubes can be cut off and then re-welded into a new row of tubes. The tubes can be re-fabricated and welded according to the above methods, and the process requirements can be strict to ensure the quality.
2.3 Rotary Valve Failure Of Conditioner
The general structure of the unloading rotary valve is composed of the unloader motor, reduction gearbox, sprocket chain and feeding roller. The main common faults are the failure of the unloader and the transmission part. Such failures are usually common mechanical failures. When a jam occurs, we usually need to check whether the two ends of the feeding roller are normal and whether there are bearing failures. The problems related to the sprocket chain failures include the failure of the transmission part, it is not necessary to introduce in detail and carry out corresponding treatment.
3 Key Points For Daily Maintenance Of Vertical Seed Conditioner
At present, major grain&oil enterprises implement the concept of TPM and planned maintenance, and closely focus on the actual characteristics of enterprise production and the model combined with TPM management, and carry out a production maintenance management model that combines planned maintenance (also called planned maintenance) with prevention. The daily maintenance of the conditioning tower is mainly carried out from the following 3 aspects:
3.1 Independent maintenance mainly by operators, mainly including independent spot inspection, cleaning and inspection, lubrication and fastening, etc.
3.2 Planned maintenance, mainly by maintenance personnel, shall deal with the problems found, such as replacement of bearing failure, maintenance of transmission parts, repair of tube sheet or tube leakage, etc.
3.3 Carry out regular parts replacement or centralized maintenance according to the equipment operation instruction or the regular maintenance content defined by the manufacturer. Such as regular replacement of bearings, seals, transmission components, etc.
In a word, in grain&oil enterprises, the importance of conditioner is self-evident. The daily maintenance and repair of equipment are crucial to the safety, stability and cost-effectiveness of enterprises and factories, the above-mentioned parts discuss the inadequacies and continue to improve, at the same time, how to properly maintain normal equipment and faulty equipment is the main direction of our efforts as equipment maintenance personnel, and also the embodiment of our own value. Strictly following technical specifications and continuous technological innovation are the cornerstone of enterprise development. In the future, we will continue to explore, accumulate broader experience in equipment maintenance and repair, and contribute to the development of the enterprise.