Why are auditorium soft chairs becoming more and more popular?

Here are five reasons why high-end auditorium soft chairs, conference hall chairs, lecture hall chairs, and solid wood auditorium chairs are popular.

The auditorium soft chair is a very common seat in our lives. It is very common in all kinds of meeting rooms and auditoriums. Even many people have placed the auditorium soft chair in their own homes. So, why are the auditorium soft chairs so common and popular? Obviously, the auditorium soft chairs must have its own unique features and functions worthy of being appreciated.

Next, we will introduce why the auditorium soft chairs are so popular among people. Mainly include the following aspects:

Auditorium-chair

First: The auditorium’s soft chairs are very practical. The auditorium soft chairs produced on the market now have a multi-functional function, can sit and lie down, have different use values ​​in different environments, and work and rest are not wrong.

Second: The materials used in the auditorium soft chairs are getting better and better, and they look more and more high-end and elegant.

Third: The shape design of the auditorium soft chair mostly uses solid wood, which looks beautiful and generous, the shape is novel and unique, and the decorative effect is very good.

Fourth: The auditorium soft chair has a unique return structure, which can save floor space and space.

Fifth: The structure of the auditorium soft chair is sturdy, durable, not easy to damage, and there will be no problems under normal conditions.

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What are the testing standards for school desk and chair sets?

The quality of school desk and chair sets are related to the health and development of students, so you must pay attention to their materials and dimensions when purchasing. There are many testing standards for school desks and chairs, such as lifting and adjusting mechanisms should have locking devices or limit devices , The parts should be free from damage, and the flap device should be equipped with buffer or damping devices, etc., which can be selected by referring to these testing standards and relevant national standards when purchasing.

What are the testing standards for school desks and chairs?

School desks and chairs are used by students, young, active, and in a high-speed period of growth and development, so school facilities and equipment managers need to pay special attention to when choosing desks and chairs for students. Health, hygiene, environmental protection and safety, so what are the safety items for student desks and chairs? What testing standards should students’ desks and chairs meet? The following are some basic items for desk and chair testing, which must be qualified before they can be used:

student desks and chairs

1. The lifting and adjusting mechanism should be equipped with a locking device or a limit device, which should be flexible, reliable and safe.

2. The gap between the relative moving mechanical device parts and the human body contact part should be ≥25mm.

3. The flipping device should be equipped with a buffer or damping device.

4. All parts and components should be undamaged.

5. The radius of the rounded corners of the seat surface, chair back and armrests that are in contact with the human body should not be less than 2mm.

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6. Some parts that may cause injury should not be accessible to students unless special disassembly tools are used.

7. Desks and chairs should not be disassembled at will, unless special disassembly tools are used.

8. Parts that use lubricating oil should be properly covered.

9. The metal parts should have no unsealed pipe fittings, and the cap should not be easy to fall off.

10. The diameter of all uncovered holes should be ≤5mm or ≥25mm.

11. There should be no burrs, blade corners, sharp edges, penetrating nails, and other sharp objects in the parts in contact with the human body and the parts where items are stored.

In summary, the purchaser must carefully check the relevant standards according to the inspection report to avoid buying unqualified and inferior products that affect the use of students.

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What is the standard for school desk and chair sets

I don’t know if you have a very suitable desk when you study before. For students, a suitable desk is really a very necessary item, especially for children who are studying. So what is the standard for school desk and chair sets?

Desk height standard

Generally, the size of a single desk is about 60CM*110CM, and the height of the table is 71-75CM. The distance between the table and the bottom of the drawer is generally 12.5CM. If it exceeds this distance, people will be hit once they get up. If the desk is a wall-mounted desk, a light trough of about 10 cm can be installed at a distance of about 45 cm from the countertop, and a closet or bookshelf can be set above the light trough, so that the eyes will not be exposed to light. Stimulation can ensure sufficient light.

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Desk height

If you are preparing desks for elementary school students, the height of the desk should preferably be adjustable, so that the desk can be adjusted according to the height of the students, so as to facilitate the healthy development of physical development, and the adjustable height of the desk is the best Control between 53-79CM, the width and depth of the desk top should be controlled between 120CM and 60CM.

In addition, it is best for the desk to be used that even the corners of the desk can be adjusted, because the best angle for writing on the desk is that the desk top can be tilted about 7 degrees, and the tilt angle of the desk when sitting in front of the desk for reading The best is 45 degrees. If the above-mentioned standards can be met, then this desk and chair can be called a standard desk and chair, and its height is also a good height.

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How to repair the school dining table and chair wear?

School dining tables and chairs also play an important role in the field of use and the scope of use. For example, wear resistance, antistatic performance and chemical resistance, etc. Among them, school dining tables and chairs with wear resistance are one of the products with a wide range of applications. So how do we repair the school dining table and chair wear

School dining tables and chairs have two wear methods: chiseling wear and high stress wear. Chiseling wear requires relatively high impact loads on fast food dining tables and chairs.

Four-stainless-steel-dining-table-and-chair

It is often used in the fields of ball mill lining, iron forging and lining bricks for vertical kilns. Since the impact force generated is not large, the wear form is mainly chiseling.

Therefore, when selecting materials, the hardness and wear resistance are mainly considered, and the wear resistance is mainly improved, but for high stress wear.

There are relatively high requirements for the hardness of the surface of school dining tables and chairs, to reduce the phenomenon of surface shedding and embrittlement, to resist the pressure caused by abrasives, and to enhance the service life and use effect.

We only understand the wear and tear of school dining tables and chairs. In the actual use process, we can avoid it through some methods to ensure the good use of the product and extend the service life of the product.

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Slewing bearing manufacturer introduction

The slewing bearing is a large support bearing that can bear a comprehensive load, and can bear large axial and radial loads and tilting moments at the same time. This product is generally equipped with mounting holes, internal or external gears, lubrication holes or sealing devices, and has the characteristics of compact structure, light weight, good structural rigidity, stable operation, high precision, safety and reliability.

As a professional slewing bearing manufacturer, Luoyang Longda Bearing Co., Ltd. develops and manufactures various bearing products with an inner diameter of 100mm or more in accordance with national standards, such as large-size, extra-large-size deep groove ball bearings, angular contact ball bearings, etc., with advanced science and technology. , Single row, double row and four row cylindrical roller bearings, spherical roller bearings, single row, double row and four row tapered roller bearings, self-aligning ball bearings, thrust ball bearings, thrust roller bearings, slewing rings, split Bearing. LDB logo, products are widely used in national ports, machine tools, mining, metallurgy, electric power, medical, heavy machinery, coal machinery, cement machinery, petroleum exploration, defense industry and other fields.

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The difference between wheel worm slewing drive and spur gear slewing drive

Worm gear slewing drive and spur gear slewing drive are both highly integrated modular rotary reducers. Users do not need to purchase individual parts one by one and then assemble them into products with worm gear slewing drive and spur gear slewing drive functions. Reduce unnecessary production preparation procedures, greatly improve production efficiency. In a sense, the spur gear slewing drive can replace all toothed slewing bearings. Compared with slewing bearings, it has the advantages of simple installation, easy maintenance, and greater saving of installation space.

So, what are the similarities and differences between the worm gear slewing drive and the spur gear slewing drive in the design and use?

1. Similarities:

Both the worm gear slewing drive and the spur gear slewing drive use the slewing ring as the main moving part. The slewing ring plays the role of driving the equipment to rotate and bearing the equipment load. The worm or gear is used as the driving part of the power input, the housing, the flange, the general support Bearings, seals, etc., as accessories, can finally achieve 360° rotation through reasonable design and assembly, can withstand large loads, and are components with deceleration function. Both types of slewing drives have the characteristics of slewing, deceleration, load-bearing, compact structure, fully sealed, dustproof and waterproof, modular design, and convenient installation and maintenance.

2. The difference:

1. The worm gear slewing drive uses a worm to drive the slewing support to rotate, and the spur gear slew drive uses a gear to drive the slewing support to rotate.

2. The reduction ratio of the worm gear slewing drive is large, and the reduction ratio of the spur gear slewing drive is small.

In the case of the same modulus and the same outer diameter, the reduction ratio of the worm gear slewing drive is equal to the number of teeth of the slewing ring; the reduction ratio of the spur gear slewing drive is equal to the number of teeth of the slewing ring/the number of gear teeth. The number of teeth of the gear is generally designed to be 15 teeth, and reduce The difference is 15 times.

3. The worm gear slewing drive has the characteristics of reverse self-locking, and the spur gear slewing drive cannot be reversed self-locking.

The worm gear slewing drive can only be driven by the worm to rotate the worm wheel, and the worm cannot be driven by the worm gear to rotate. The reverse self-locking makes the slewing drive widely used in lifting equipment, high-altitude operations and other equipment. Under such working conditions, the worm gear slewing drive is used No braking device is required, and the equipment can remain stationary for a long time without power. The spur gear slewing drive gear can drive the gear ring to rotate, and the gear ring can also drive the gear to rotate in reverse. It cannot achieve reverse self-locking. This feature is also used in some special fields, such as wood grabbers, snow sweepers, etc. Collision cannot be avoided during the use of the equipment, and it does not self-lock when a collision occurs, which acts as a buffer and protects the equipment.

4. The worm gear slewing drive has a low speed limit, and the spur gear slewing drive has a high speed limit.

The worm gear slewing drive is a worm gear drive, and the worm gears slide between each other. High-speed rotation is easy to generate heat, causing the worm to overheat and lock or directly damage. Generally, the rotation speed of the worm gear slewing drive does not exceed 2.5 rpm; gear type slewing drive It is the tooth-to-tooth meshing that works, it is not easy to generate heat, and the speed can usually reach 40-60 rpm.

5. The transmission efficiency of the worm gear rotation drive is low, and the transmission efficiency of the spur gear rotation drive is high.

The worm gear slewing drive has high friction between the worm wheel and the worm, and the transmission energy loss is large, so the transmission efficiency is low, usually only 30%-40%; the friction resistance between the spur gear slewing drive gears is small, and the loss is small, so the transmission efficiency is high. Generally, it can reach 90%-95%, which is very efficient and energy-saving.

6. The worm gear slewing drive has low slewing accuracy, and the spur gear slewing drive has high slewing accuracy.

The rotation accuracy of the ordinary worm gear slewing drive is affected by various factors, and can not achieve a small backlash. Generally, the precision of the precision type can reach within 0.05°; the spur gear rotation drive has high rotation accuracy, and the gears and ring gears can be grounded. The processing method can achieve high precision, and the precision of the gear type rotary drive with a diameter of 1 meter can reach within 0.01°.

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Introduction to the heat treatment process of double row ball slewing bearing

The double-row ball slewing bearing is called “mechanical joint” in the machinery industry. It is the primitive mechanical transmission necessary for relative rotation between two objects, and can bear axial force, radial force and overturning moment.

Heat treatment of double-row ball slewing ring bearings and gears:

The raceways of the double-row spherical slewing ring are surface induction hardened, and the hardening hardness ensures that the depth of the hardened layer can be reached under HRC55 to 62.

Due to the need for transmission, the double-row ball slewing ring is usually made of one of the rings. The heat treatment state of the gear is usually normal or quenched and tempered. The tooth surface can also be quenched according to user requirements, and the quenching hardness is HRC50~60, which can ensure sufficient depth. According to different applications, gear quenching can be divided into full-tooth quenching and single-tooth induction quenching. Single tooth induction hardening can be divided into tooth surface tooth root quenching and tooth surface quenching.

Double-row ball slewing bearing, adapt to temperature and working environment:

Slewing-Bearings

The double-row ball type slewing bearing can work at a temperature of -300C~700C. Users need to adapt to lower or higher temperature double-row ball slewing bearings. The double-row ball slewing ring is the same as other ordinary bearings. They have rolling bearings and races, but they are different. The double-row ball slewing bearing has many different characteristics.

The size of the double-row ball slewing bearing is relatively large, usually 0.2-10 meters in diameter, and some can even reach 40 meters.

Generally, the double-row ball slewing bearing must not only bear the axial force and the radial force, but also bear a greater overturning moment, so as to bear a variety of loads. Therefore, a set of double-row ball slewing bearings usually play the role of several sets of ordinary rolling bearings.

The double-row ball slewing ring runs at a lower speed, usually 50 rpm. In many cases, the double-row ball slewing ring cannot work continuously, but can only operate at a rotation angle (equivalent to the so-called “slewing bearing”).

In the manufacturing process such as materials and heat treatment, double row ball slewing bearings and rolling bearings are also very different.

Generally, the double-row ball slewing bearing has a gear ring for rotating drive and a sealing device for dust prevention.

The installation method of the double-row ball slewing bearing is different. It is not like ordinary spindle bearings, but installed in the bearing box, but fixed in the upper and lower bearings by screws.

The double-row ball type slewing ring is also called “slewing ring” because its shape is similar to that of a plate, so it can bear the comprehensive load of a large bearing. It can also withstand greater axial loads, radial loads and overturning moments. Used in combination with ordinary bearings. Use function. Usually suitable for bearing huge overturning moment and relative rotation of mechanical equipment. It is an efficient and high load bearing combined bearing.

Therefore, due to the special nature of the double-row ball slewing bearing, the double-row ball slewing bearing has been applied to a large extent.

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Instructions for Micro Sample Nucleic Acid Extraction Kit

The micro sample nucleic acid extraction kit is a kit specially used to extract DNA and RNA from various micro and trace samples. This kit uses a centrifugal adsorption column that can specifically bind nucleic acids and a unique buffer system. After the sample is lysed, the DNA is specifically bound to the silica gel membrane under high salt conditions, and the DNA is washed from the silica gel membrane at low salt and high pH. Take it off.

This kit is used to extract genomic DNA and mitochondrial DNA from small amounts of blood, dried blood spots, chewing gum, swabs, urine, and small amounts of tissues. It can also be used to purify genomic DNA obtained from other methods. DNA can be directly used as PCR template, enzyme digestion, hybridization and other molecular biology experiments.

Features of Micro Sample Nucleic Acid Extraction Kit

1. The recovery rate of nucleic acid is high, which can reach more than 90%

2. One-tube operation reduces the possibility of sample contamination.

3. One-stop kit, customers do not need to prepare any reagents except samples, which reduces experimental errors.

4. Safe and non-toxic, no need to use organic solvents such as phenol and chloroform.

5. It can handle samples of various forms, including liquid samples, single or small amount of cells, tiny embryos and so on.

6. Compatible with PCR, fluorescent PCR, RT-PCR, fluorescent RT-PCR and other follow-up reactions.

7. The reagent is stable and can be stored for a long time.

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Nucleic acid extraction system application field

Nucleic acid extraction system, also called nucleic acid purification instrument, is an instrument that uses matching nucleic acid extraction reagents to automatically complete sample nucleic acid extraction. An instrument that has only been applied and promoted in recent years.

Nucleic acid extraction system application field

In almost every laboratory, the separation and purification work related to biomolecules is very important and indispensable. However, it is still quite difficult to purify multiple samples. It is not only necessary to select a suitable purification technology, but also the workload is particularly large, which is difficult to meet the current rapid development of high-throughput sample extraction and purification needs. The magnetic bead automatic nucleic acid extraction and purification system uses magnetic bead technology, which can be widely used in genomics, disease control and medical care, food safety, forensic identification and other fields.

Genomics

The automatic nucleic acid extraction system is very suitable for genomics research. Samples can be extracted from microorganisms, animals, plants, or viruses. Whole blood genomic DNA extraction kits, leukocyte layer whole blood genome extraction kits, animal tissue/cell genomic DNA extraction kits, can quickly purify sufficient quantities and Pure DNA or RNA. High-quality nucleic acid can meet the needs of various downstream applications (such as PCR/Real-time PCR, gene chip, Southern blot, Northern blot).

CDC

The automatic nucleic acid extraction system can be used to solve the rapid automatic disease monitoring system of Influenza A virus subtype H1N1, children’s hand, foot and mouth disease, measles virus, etc., and improve the response ability of major epidemics.

Molecular diagnosis of clinical samples

The automatic nucleic acid extraction system can process clinical samples quickly and with high throughput, and the extracted nucleic acid can be used for subsequent molecular diagnosis. It is also suitable for formalin-fixed and paraffin-embedded (Formalin-Fixed and Parrffin-Embedded, FFPE) tissue samples.

Animal Husbandry and Veterinary Medicine

It can extract Avian influenza virus (Avian influenza virus), Newcastledisease virus (Newcastledisease virus), Classical swine fever virus (CSFV), Bovine viral diarrhea virus (Bovine viral diarrhea virus), Rickett. Secondary body (Coxiella burnetii) and so on.

Forensic applications

For forensic work, the efficiency and stability of nucleic acid extraction are very important. The automatic nucleic acid extractor is used in conjunction with a special forensic sample nucleic acid extraction magnetic bead reagent to purify high-quality DNA from materials from different sources including cigarette butts, hair roots, cartilage, nails, and blood stains.

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Introduction of Lining Trolley Traveling System

The lining trolley is driven by the driving wheel to wind the crawler and cyclically rotate, and it is a mechanism that supports the body. It is composed of crawler walking device and suspension. The lining trolley walking system often adopts the overall trolley traveling system and the balancing trolley traveling system. The walking device of the lining trolley consists of crawlers, driving wheels, supporting wheels, supporting wheels, tensioning wheels and tensioning buffer devices. The engine transmits the torque to the driving wheels through the transmission system, and drives the crawler belt to move in a circular motion, which becomes an infinitely long moving track carried by itself. There are two types of crawler: metal crawler and metal rubber crawler. The most widely used metal crawlers are combined type and integral type.

It is composed of track, driving wheel, supporting wheel, supporting wheel, tensioning wheel and tensioning buffer device. The engine transmits the torque to the driving wheels through the transmission system, and drives the crawler belt to move in a circular motion, which becomes an infinitely long moving track carried by itself. There are two types of crawler: metal crawler and metal rubber crawler. The most widely used metal crawlers are combined type and integral type. The combined track is composed of track section, track shoe, track pin and pin sleeve. Each track shoe is fixed on the track section with bolts, and each track section is connected to each other by a track pin with a pin sleeve. The track shoe can be made of special-shaped steel such as high-quality carbon steel or alloy structural steel. The combined crawler has high rigidity, good sealing performance and long service life, and different types of crawler shoes can be replaced according to needs.

But it is heavy and inconvenient to disassemble and assemble. The track shoes of the monolithic track are mostly cast from wear-resistant alloy steel, and each track shoe is directly connected to each other with track pins, which has a simple structure, light weight, and convenient disassembly and assembly. However, the gap at the pin hole is large, the sand is easy to enter, and the service life is short. The use of bimetallic track pins with chrome steel surface or track pins with rubber bushings can extend the service life. The metal rubber track uses rubber as a connecting piece, and has two types: block type and whole strip type. Each section of steel spurs is integrated with a rubber block or a whole rubber belt. There is no noise when working, and can alleviate the impact, and has a long service life, but the rubber is easy to age.

The supporting wheel is used to transfer the weight of the lining trolley to the crawler belt and play a supporting role; the tension wheel and the tension buffer device are used to guide the crawler belt to move normally and maintain a certain degree of tightness of the crawler belt. When the tension wheel is impacted, it can slide or swing backwards to alleviate the impact, and adopts screw type or hydraulic type tensioning mechanism. The screw type structure is simple, but the adjustment is laborious; the large and medium-sized lining trolley should adopt a hydraulic tensioning mechanism. The role of the supporting roller is to support the crawler, reduce the amount of sag of the crawler, and prevent the crawler from jumping and lateral slippage. Some supporting rollers use rubber rims to reduce noise and prolong service life.

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