The mixing drum is the key component of the concrete mixer truck for loading, mixing and transporting concrete. A flange is welded at the head of the mixing drum, and a raceway is welded at the rear cone. The mixing drum is driven by the reducer, and is supported by the rollers in rolling contact with the raceway to rotate, so as to realize the loading and unloading and mixing functions of concrete. Due to the eccentric load generated by the concrete mixer truck during mixing and the starting and braking of the vehicle on complex roads, the force on the mixing drum is extremely complex, and the design or welding process defects may lead to cracking of the raceway welds. The concrete mixer truck manufacturer analyzes the cause of the cracking of the raceway weld and proposes a repair plan.

Cause Analysis of Weld Cracking

When the mixing drum is working, in addition to the bending moment caused by the self-weight of the drum and the weight of the concrete, it also bears the torque action caused by the rotary motion of the mixing drum and the force of the concrete in the circumferential and axial directions in the mixing drum. force is more complicated. Under the action of cyclic alternating load, initial micro-cracks may form in areas of high stress, and then develop into macro-cracks, and then the macro-cracks will continue to expand, eventually leading to cracking of the weld bead or base metal.

The main reasons for the initial microcracks affecting the raceway are as follows:


(1) Stress concentration at the raceway weld

Reason: When the raceway and the cylinder are welded, stress concentration often occurs at the weld. In addition, during the use of the mixing drum, the concentrated load at the raceway and the supporting roller and the overall deformation of the raceway section will also cause stress concentration at the weld.

Countermeasures: Grind the stress concentration weld and re-weld. For the weld or base metal with macro cracks, punch holes to cut off the source of the crack and re-weld.

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Cold forging is a general term for plastic processing such as cold die forging, cold extrusion, and cold heading. It is the forming process of the material below the recrystallization temperature, and the forging is carried out below the recovery temperature. In production, forging without heating the blank is called cold forging.

Most of the cold forging materials are aluminum and some alloys, copper and some alloys, low carbon steel, medium carbon steel, and low alloy structural steel with low deformation resistance and good plasticity at room temperature. Cold forgings have good surface quality and high dimensional accuracy, which can replace some cutting processes. Cold forging can strengthen the metal and increase the strength of the part.


Locomotive forgings

Cold precision forging is a (near) net shape forming process. The parts formed by this method have high strength and precision and good surface quality. At present, the total amount of cold forgings used in an ordinary car abroad is 40~45kg, of which the total amount of toothed parts is more than 10kg. The single-piece weight of cold forged gears can reach more than 1kg, and the tooth shape accuracy can reach 7 grades.

Continuous process innovation has promoted the development of cold extrusion technology. Since the 1980s, domestic and foreign precision forging experts have begun to apply the split forging theory to the cold forging of spur and helical gears. The main principle of shunt forging is to establish a shunt cavity or shunt channel of material in the forming part of the blank or die.

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During the operation of the excavator, the rotating ring gear bears a large impact load. When the excavator is inclined, the stress state is even more unfavorable. Generally, when the excavator runs for about 350,000 hours, the teeth of the rotating ring gear may be crushed or broken. Practice has proved that the use of insert welding to repair the rotary ring gear is not only simple and fast, but also ensures the performance of the whole machine.

1. Preparation before welding

Excavator slewing bearing

(1) According to the damage of the ring gear, determine the position of the fixing hole and the damaged segment to be replaced, and then cut off the segment of the tooth to be replaced with gas cutting.

(2) According to the part of the ring gear that needs to be repaired, process the insert, or from the corresponding part of another old ring gear, under the condition of ensuring the pitch, cut out a relatively intact gear tooth, and cut out the butt joint. Bevel shape.

(3) Determine the position of the fixing hole of the insert, and punch it to fix it on the corresponding part of the ring gear. Pay attention to the accuracy of the position of the fixing hole.

(4) In order to ensure that the welding seam has high strength and can withstand large shocks and vibrations, a junction 507 electrode with a diameter of Φ4 mm is selected.

(5) Using AX3500 DC arc welding machine DC reverse welding, the current is 130 ~ 140 A.

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Crossed cylindrical roller bearing is a common rolling bearing, which is widely used in all walks of life. Crossed roller bearing is also a consumable, because incorrect installation or operation will affect its service life, and in serious cases, it will lead to bearing failure. If it is damaged, the bearing has to be replaced in time to make the equipment run normally. Below, the manufacturer of the crossed cylindrical roller bearing will introduce the correct installation method and precautions of the crossed cylindrical roller bearing!

Installation steps of crossed cylindrical roller bearings

Crossed cylindrical roller bearing

1. Check before installation

Thoroughly clean the spindle, bearing housing or other mounting parts, remove oil or impurities, and check for burrs or burrs. After confirmation, the spindle, housing and components are ready to start installation.

2. Install the bearing

When the crossed cylindrical roller bearing is installed in the shaft or the bearing housing, because it is a thin-walled bearing, it is easy to tilt during installation. In order to prevent this phenomenon, it is necessary to use a plastic hammer evenly while keeping it level, and carefully install the crossed cylindrical roller bearing into the bearing housing or the shaft little by little until it is confirmed by sound that it is completely abutted with the reference surface. until.

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Many companies will face different prices in the process of purchasing heavy-duty shelves, or the prices given by different manufacturers of two shelves with the same surface will be different, so how can we purchase heavy-duty shelves suitable for enterprise warehouses? ? What are the reasons that affect the price changes of heavy duty shelves?

Reasons affecting the price changes of heavy shelves

Industrial racking

1. Production materials

The raw materials produced by the heavy-duty shelves are different, and the prices of the raw materials will also be different, which will affect the cost of the shelves, so the prices of the produced heavy-duty shelves will also be different.

2. Heavy duty rack structure

The price of the heavy-duty shelf structure is also different. The main structural firmware of the shelf is the column, the beam and the laminate. The thickness and specification of the plate are the determining factors of the shelf price.

3. The location of the shelf manufacturer

Depending on the location of the manufacturer, local taxes, factory rent, and the cost of goods in the transportation process are the hidden costs of heavy-duty shelves in the production process. These factors also affect the production cost of heavy-duty shelves.

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Valve bags are very popular in the domestic market, especially in the small commodity wholesale market and the food industry. Many people who make it do not know that this kind of bag is made by a special valve bag making machine. What is the working process of the valve pocket bag making machine, let’s learn more about it together!

The working flow of valve bag making machine

HT120-IA Paper Tube Machine

1. Hopper feeding

The bag making machine is a hopper on which the powder is transported to the packaging machine by the feeder throughout the day. Device Control. The sealing paper roll is driven by the guide roll to the lapel forming machine. After bending, it is lapped into a cylinder with a longitudinal sealer. The material of the bag making machine is automatically measured and then loaded into the bag. The transverse sealer intermittently pulls down the bag cylinder while cutting off the heat seal to form a flat bag with overlapping longitudinal seams on three sides, and seals the seal of the bag.

2. Cutting

How to carry out the cutting of the bag making machine, the metal cutting process of the bag making machine is actually very similar to the metal extrusion process. When the gravure printing machine cuts plastic materials, the material begins to elastically deform under the action of the tool. As the tool continues to cut in, the stress and strain inside the metal continue to increase. When the stress reaches the yield point of the material, plastic deformation begins; Using computer control, the advanced (servo) fixed-length system makes the sealing and cutting size error small, and the electric eye is installed to make the printed pattern position. The length of the bag can be adjusted by computer numerical control. If there is a problem with the printing bag, the machine will automatically stop and give a warning sound.

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The technical process of the lime equipment is to add raw quicklime from the loader to the silo, evenly add it to the jaw crusher through the vibrating feeder, and crush it to about 30-50 mm. The dust generated during the crushing process of the equipment is introduced into the pulse bag filter outside the workshop by the induced draft fan through the dust cover of the jaw crusher, and the calcium oxide powder of the dust collector should be cleaned once a week.

The hydrated lime equipment adopts a double-shaft stirring structure, which has various functions such as stirring, crushing and agglomeration, and self-cleaning. Its unique paddle and stirring formula make the quicklime and water mix evenly, the reaction is sufficient, and it plays a role in the agglomeration generated during the reaction.

GFX Stepped Case


The feed port of the digester is designed with a screw feed propeller to facilitate material transportation. In order to prevent the backflow of dust generated in the digestion process, the equipment is equipped with a special discharge port for steam and dust, which can be discharged to a special dust removal system through connecting pipes, and is used in conjunction with the DMC pulse dust removal Q device with the hydrated lime equipment, which can handle quicklime well. Dust and harmful gases produced during digestion. Waste dust and lime can be reused after use, and the environment has no dust pollution, which meets the requirements of environmental protection development.

The quicklime crushed by the hydrated lime equipment is lifted by the bucket elevator to the lime silo at the upper part of the digestion tank in the digestion workshop. The quicklime is evenly fed into the digester through the plug-in valve at the lower part of the lime silo and the weighing feeder (the feeding speed is 5t/h). At the same time, water was added to the digester at a ratio of 133603.5 (17.5 m3/h).

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As a commonly used screening equipment in the mining industry, the vibrating screen is in a long-term working state and the operation is also a fine operation, so there will be more or less problems. If the feeding is too slow, it will affect the screening efficiency of the vibrating screen. The reasons for the slow feeding of the vibrating screen and the adjustment methods have been introduced in detail below. Let’s take a look.

The reason why the vibrating screen feeds slowly

High frequency dehydration vibrating screen

1. Vibration motor problem

(1) The motor power cannot reach or the motor power is normal but the speed is slow, and the 1500 rpm that cannot be used will also cause the feeding to be slow.

(2) The steering problem of the vibration motor: the steering of the motor is divided into two types: forward rotation and reverse rotation. Under normal circumstances, the steering of the two motors is in the opposite direction, but if the user connects the positive and negative poles incorrectly when the power is connected, it will cause When the motor rotates in the same direction, there will be a problem of slow or no material feeding on the screen surface.

(3) The problem of the installation position of the motor: There are three installation positions of the vibrating motor of the linear screen, which are the bottom, the two sides, and the upper part. If the vibration motor is installed close to the feeding port, the screen surface material will run for a certain distance and then the speed will decrease and stay on the screen surface.

2. The amount of screen cloth is too large

The excessive amount of cloth on the screen surface is also the reason for the slow feeding of the vibrating screen. When the screen is added, the load of the motor is also added accordingly, and there will be a problem of slow feeding.

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At present, briquetting machine manufacturers basically have products of various specifications and models for users to choose from. Generally, the appropriate model is selected according to its own production capacity. But some customers have a misunderstanding about the size of the output, that is, only buying a larger briquetting machine can increase the output. So what are the factors that affect the output of the briquetting machine?

Factors affecting the output of briquetting machine

briquetting machine

1. The performance of the equipment itself is a key factor in determining the output of the briquetting machine. If you choose a briquetting machine, but because its quality is not good enough, there are often problems during use, so no matter what model you choose , are all useless. Therefore, the efficient operation and trouble-free operation of the briquetting machine equipment is an important condition to ensure production.

2. A single briquetting machine cannot be produced on a large scale, so many companies will build a briquetting machine production line, and the structure of the production line is also very complicated. In addition to the briquetting machine, there are also crushers, conveyors, dryers, etc. There are many kinds of machinery, so the production capacity of the briquetting machine alone is high, and the production capacity of other components cannot keep up.

3. Whether the connection between the various processes in the whole production process is smooth and efficient. This is a very delicate work. If any part of the production line is not running smoothly, the efficiency of the entire production will be affected. Therefore, in order to improve production efficiency, in addition to purchasing high-capacity equipment, other aspects need to be in place.

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As an important part of the tractor, the clutch must be reasonably matched to fully satisfy the use of the tractor clutch. It needs to be lubricated in the process of use. Then in the process of selecting lubricating oil, what should we do? to operate it?

We want to make high-quality lubricating greases from base oils, thickeners and additives. The performance of different types of greases with different grades of the same type is very different, and the allowable rotation limits are also different. Therefore, the tractor clutch must be clear when choosing!

1. The choice of diesel

Diesel is divided into light and heavy diesel, and agricultural tractors generally use light diesel. Light diesel oil is generally divided into No. 10, No. 0, -10, -20, -35 and other grades according to its freezing point. In order to save money, in many areas, apart from those who are engaged in transportation in the cold winter, they need to prepare -35 oil. Generally, they only need to prepare two kinds of diesel oil, 0 and -20, for agricultural production. Use No. 0 diesel in summer and No. 11 in winter. In other areas, the appropriate number of diesel can be selected according to the specific local temperature.

2. The choice of oil

Diesel engine oil is required for agricultural diesel engines. Diesel engine oil is divided into three types: No. 8, No. 11 and No. 14. Generally, use No. 8 oil in summer and No. 11 oil in winter.

3. Selection of gear oil

Gear oil is divided into 20th and 309th. 30 in summer; 20 in winter. Here to remind the owners of the machine, it is strictly forbidden to use engine oil instead of gear oil, or to mix diesel and kerosene in the gear oil, so as not to reduce its viscosity, weaken the lubricating performance, and accelerate gear wear.

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