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What Is a Shaking Machine?

Figure1. Typical Shaking Machine

A shaking machine is a machine that shakes and agitates a sample in a container, such as a test tube, flask, or aliquot funnel.

It is also called a shaker. Shakers are often used for time-consuming sample separation, elution, dissolution, and cultivation of aerobic microorganisms.

There are various types of shakers, such as reciprocating, swiveling, and figure-8 shakers, as well as horizontal and vertical shaking directions, depending on the model. Some models are equipped with heating and cooling functions, and can also be used for shaking culture.

There are also sieve shakers that can be used to sieve powders as well as liquids.

Uses of Shakers

Shakers are generally used in the life sciences and chemistry for experiments that require long periods of constant shaking. The main applications in the testing field include various dissolution tests, dissolution of samples, and cultivation of aerobic microorganisms.　

In particular, elution tests for soil environmental require the elution of heavy metals in soil by a shaker under specific conditions. In the culture of aerobic microorganisms, the conditions vary depending on the microorganism. It is necessary to calculate the shaking width and shaking speed of the Shaker and to adjust the appropriate oxygen transfer rate.

Other applications include the elution of dioxin and residual pesticides in vegetables with hexane, for example, to test for residual pesticides in food products and to analyze eluted components of industrial waste.

Principle of Shakers

Figure 2. Temperature-controlled shaker

The shaker has a power unit built into the base of the shaking table. The power unit transmits power from the motor to the pulleys via a belt, which converts the rotation of the motor into a reciprocating motion of the shaking table.

Models with a temperature control function have a heater or cooling system under the base. In some cases, the thermostatic bath and shaker are integrated.

Depending on the model, the size of the base can be changed according to the use of the shaker. Some models can be optionally reshaped by placing a special plate for each vessel on top of the base to make it easier to use according to the respective vessel.

Powder sieve shakers use electromagnetic magnets to generate vertical vibrations in the oscillator. A spring adjusts the amplitude of the oscillation, and the sieve is shaken vertically.

Types of Shakers

Figure 3. Various shaking machines

Shakers come in a variety of sizes: small, medium, and large. The choice should be made according to the application and the size and shape of the container. For example, a large shaker should be used for elution tests in soil analysis.

For an in vitro test with a small amount of sample, a small shaker should be selected. In particular, a small shaker should be used when the sample is placed in an incubator for microorganism or cell culture applications. This type of shaker is designed to handle ambient temperatures from about 0 to 50°C and ambient humidity up to about 95% RH.

Most small tabletop shakers fit in the size range of approximately 200 to 300 mm (width) x 180 to 250 mm (depth) x 100 to 170 mm (height). The upper limit of allowable load weight is about 2 kg for most models. Swing types include reciprocating, swiveling, seesaw, horizontal eccentric, figure-8, and other types, with horizontal and vertical directions. Some models incorporate multiple shaking methods that can be switched manually.

Shaking speed can be changed within a range of approximately 20 to 200 rpm. The step- or non-step type depends on the product, and many models have a built-in timer.

What is a Thermal Analyzer?

A thermal analyzer is a generic term for a device that measures changes in a sample when heat is continuously applied to it. It consists of a mechanism for continuously changing the temperature of a sample and a mechanism for detecting and recording the physical properties to be measured. Different analysis names are given to each of these devices depending on the physical property to be measured.

The analyses performed using thermal analyzers include Differential Thermal Analysis (DTA), which analyzes the temperature difference between a measurement sample and a standard sample, Differential Scanning Calorimetry (DSC), which analyzes the difference in calorific values, and DSC Calorimetry (DSC) to analyze differences in heat content, Thermogravimetry (TG) to measure weight changes, and Thermomechanical Analysis (TMA) to measure changes in length.

Uses of Thermal Analyzers

Thermal analysis using a thermal analyzer is used to measure the thermophysical properties of any material. The structure and state of materials change with temperature changes, and the properties and functions of materials change accordingly. Understanding the behavior of materials in response to changes in temperature is very important for controlling properties and quality, and for understanding exothermic/endothermic behavior during reactions.

In a typical thermal analysis, phenomena such as glass transition, crystallization, melting, and decomposition caused by heating are traced graphically with temperature on the horizontal axis and each parameter (weight change, dimensional change, etc.) on the vertical axis. For example, in TG-DTA analysis, by simultaneously measuring the sample weight change when the sample temperature is changed and the temperature difference between the sample and reference material, it is possible to analyze what kind of change occurs at what temperature in the material.

Studies are also conducted to observe changes in morphology by combining thermal analysis with measurements with an optical camera or optical microscope or to analyze gases using gas chromatography simultaneously.

Principle of Thermal Analyzers

A thermal analysis instrument consists of a detection section, a temperature control section, and a data processing section. The detection section is equipped with a “heater,” “sample mounting section,” and “detector,” and it heats and cools the sample and detects its temperature and physical properties.

The configuration of the detector varies depending on the thermal analysis to be performed. DTA and DSC, which measure temperature, measure the temperature difference between a standard and measured substance. The temperature control section controls the heater temperature according to the program set before the measurement. In the data processing section, signals from the detector are input and recorded, and the obtained measurement data is analyzed.

Analysis Methods of Thermal Analyzers

Various methods are used in thermal analysis depending on the characteristics of the object to be analyzed. There are five analysis methods commonly used in thermal analysis: differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermogravimetry (TG), thermomechanical analysis (TMA), and dynamic viscoelasticity measurement (DMA).

The details of each method are as follows:

1. Differential Thermal Analysis (DTA)

When a sample itself undergoes a transition or undergoes some kind of reaction due to a temperature change, a change in the temperature difference from a reference material occurs, and this change is detected. This allows us to detect reaction phenomena such as melting, glass transition, crystallization, vaporization, and sublimation.

The glass transition is sometimes difficult to detect with DTA because the temperature change is more gradual than other state changes. In the case of unknown samples, it is difficult to understand the reaction phenomena by DTA curves alone fully, so data interpretation methods are often used in combination with thermogravimetry (TG).

2. Differential Scanning Calorimetry (DSC)

A reference material and a sample are similarly subjected to temperature changes, and thermocouples detect their respective temperatures. If there is a temperature difference, the temperatures are heated by a heater so that the temperatures are the same. DSC measures the energy required for this heating. This is why it is called differential scanning calorimetry. In general, it can be measured with higher precision than DTA. It can measure transitions, such as melting, glass transition, and crystallization, as well as specific heat capacity. 

3. Thermogravimetric Measurement (TG)

A reference material and a sample are similarly subjected to temperature change, and the weight difference between the reference material and the sample is tracked (a reference material that does not change in weight in the measurement temperature range is used). The sample to be measured undergoes reactions that change its mass, such as sublimation, evaporation, pyrolysis, dehydration, etc., as a result of temperature change. Since not only the weight change but also the sample temperature change can be measured at the same time to detect changes in the state of the sample, analyzers that can simultaneously perform DTA analysis are in widespread use. 

4. Thermo-mechanical Analysis (TMA)

A probe is applied to the sample to detect displacement due to temperature change. Measuring the displacement while changing the load applied to the sample is also possible. The main measurement targets are thermal expansion, thermal contraction, glass transition, curing reaction, and examination of thermal history, which are phenomena in which the shape changes due to temperature change. Melting and crystallization can also be detected because shape changes accompany these reactions. Still, care must be taken to maintain constant contact between the probe and the sample to ensure proper detection.

5. Dynamic Viscoelasticity Measurement (DMA)

A cyclic load is applied to the sample, and the strain generated in the sample is detected and output as a function of temperature or time. This instrument is used to examine glass transition, crystallization, and thermal history, which are reactions involving intramolecular motion and structural changes. The initial state of melting can also be measured, but as with TMA, measurement becomes impossible as melting progresses and the shape changes.

Other information on Thermal Analyzers

Applications of Thermal Analyzers

As mentioned above, the combination of an optical microscope and other devices is applied to various research. In the method of real-time observation of changes in morphology and coloration in combination with optical microscopes, it is possible to observe the white cloudiness of samples associated with crystallization and liquid crystal transition, as well as changes in samples near the temperature of state change.

Other analyzers have been developed to analyze gases produced during heat treatment by combining thermal analyzers with devices such as FT-IR (Fourier Transform Infrared Spectrometry) and MS (Mass Spectrometry). By combining information on thermophysical properties obtained by thermal analysis with information on gases, a deeper understanding of the thermal response of materials can be obtained. In combination with other temperature-generating devices, thermal expansion and contraction can be observed in various situations.

What Is a Glove Box?

A glove box is a device that enables work in a sealed environment by integrating a glove and a sealed container. They are mainly used when performing work where contact with the outside air or humans is undesirable. For example, cell culture work or work involving the handling of gases harmful to the human body.

Glove Box Applications

Glove boxes are used in many laboratories, mainly in the biological field, such as cell culture and in materials research, where contact with the outside air can cause some kind of reaction.

In the field of materials development, in particular, the outside air contains not only oxygen, which causes oxidation but also moisture, which causes corrosion. Therefore, experiments in the open air often cause unexpected reactions, making it an inadequate experimental environment.

In such cases, gloveboxes were invented to allow manual experiments to be conducted while keeping experimental specimens in a space isolated from moisture and oxygen.

Types of Glove Boxes

Glove boxes can be broadly classified into two types based on differences in their internal cleanliness control mechanisms.

1. Vacuum-type Glove Box

One is a glove box in which the internal space is evacuated once and then filled with an inert gas such as nitrogen or argon.

2. Displacement-type Glove Box

The other type of glove box is a displacement glove box, in which the interior is replaced by an inert gas without drawing a vacuum.

The vacuum-type glove box, in which a vacuum is pulled once, can create a space with a high level of cleanliness because impurities such as moisture and oxygen inside the glove box can be wiped out.

In addition, if the sample to be placed in the glove box is very reactive, it is likely to react with the container body and the glove as well. Therefore, to accommodate highly reactive samples, it is necessary to appropriately select a wide range of materials for the body and glove, from plastic to stainless steel.

How to select a Glove Box

In general, a vacuum-type glove box provides a cleaner space but requires a vacuum pump as accessory equipment. These are often expensive and a bit large for simple experiments in which the environment is not severe. For this reason, it is a good idea to start with a displacement-type glove box when using it for experiments that are relatively less dependent on the surrounding environment or when introducing it.

In either case, however, it is important to select materials for the body and glove that are not reactive to the sample you plan to experiment with.

Additional Glove Box information

1. Glove Boxes and Inert Gases

Nitrogen is frequently used as an inert gas, not only in glove boxes. For example, it is used as a purging gas for food packages due to its inert properties, and it is also frequently used in electronics-related factories, such as those in the semiconductor field.

Nitrogen is readily available in the atmosphere at a volume ratio of approximately 78.1%, making it cost-effective. Its specific gravity is 0.97, which is slightly lighter than air = 1.

Argon, on the other hand, is also present in the air, but at only 0.93% by volume. However, it is still the third most abundant gas in the atmosphere. As a noble gas, argon is even less reactive than nitrogen. Its specific gravity of 1.38 makes it heavier than nitrogen or air, so it accumulates in the glove box and pushes air out from above.

Argon gas is required when a more inert environment is required. In addition, maintaining the pressure inside the glove box higher than atmospheric pressure prevents atmospheric air from entering through the slightest gap in the glove box, thus maintaining a cleaner environment.

2. Moisture removal inside the Glove Box

After the inside of the glove box is replaced with inert gas, moisture may be generated when the desired reaction proceeds. Moisture in the glove box is removed by a moisture adsorbent. The adsorbent may be activated carbon or a special material called a molecular sieve.

Molecular Sieve Description
A molecular sieve is a crystalline zeolite. It is a porous crystal, and impurities in the glove box are removed by the adsorption of molecules into these pores. Naturally, the adsorption characteristics can be controlled by changing the crystal structure, so if you want to absorb only specific organic gases, it is important to select a molecular sieve that matches your application.

In recent years, a wide variety of molecular sieves have become available. As mentioned earlier, it is possible to select the adsorption target by controlling its crystallinity. In most cases, adsorption is possible under conditions where the effective diameter of the molecule is <0.3 nm, <0.4 nm, or <0.5 nm.

If all you want to do is to remove moisture, you only need to select those with <0.3nm and it is possible to create an ultra-low humidity atmosphere with a dew point temperature of -76°C or lower (moisture content: 1ppm or lower). A molecular sieve that has absorbed moisture can be regenerated and reused by flowing inert gas or by vacuum heating.

3. Oxygen removal in Glove Boxes

Removing oxygen is also important when an anaerobic environment is required or when handling materials that are highly reactive to oxygen.

Two types of catalysts can be used to remove oxygen: oxygen adsorbents such as nickel and copper and precious metal catalysts such as palladium and platinum.

When oxygen adsorbents are used, an inert gas containing several percent hydrogens must be passed through the catalyst to regenerate it, whereas precious metal catalysts do not require a regeneration gas during regeneration. Although the introduction cost of precious metal-based catalysts is higher, they are safer and have lower running costs because they do not use hydrogen-mixed gas.

4. Points to note when using a Glove Box

Due to the sealed nature of the glove box, dirt tends to accumulate inside the glove box due to reagents, etc. Therefore, it is necessary to clean the inside of the glove box to prevent contamination.

In addition, although the glove box can create an atmosphere of less than the ppm order in terms of moisture and oxygen, the environment deteriorates rapidly if only a small amount of air is introduced. To maintain a strict environment inside the glove box, it is important to remove moisture and oxygen properly when reagents are placed inside the glove box and to perform regular maintenance to prevent holes in the gloves.

What Are Cartesian Robots?

Cartesian Robots, also known as gantry robots, operate by moving along two or three orthogonal axes. Their straightforward structure makes industrial robots a common choice for automating various tasks across a wide range of industries.

Since they have at most three Cartesian coordinates, they can be made by hand and can be easily modified. Another feature is that the program that performs the work can be easily modified.

Therefore, if the work does not require complicated motions and involves monotonous movements, Cartesian Robots can be used to mechanize the work relatively easily.

Applications of Cartesian Robots

Cartesian Robots are mainly used in the manufacturing industry for simple tasks such as assembling and transporting parts. In this field, Cartesian Robots are often introduced because linear motion is sufficient to perform these tasks.

First, the line along which the parts will flow is determined. Then, by using a camera or other means, the work from assembly to transport is broken down and replaced by Cartesian Robots. The introduction of the system enables stabilization of productivity.

Specifically, Cartesian Robots are used for small precision mechanical parts, automotive parts, electronic parts for board mounting, as well as in the medical and pharmaceutical fields. In the food field, for example, specially processed arms can precisely grip and move delicate foods, such as tofu, which is fragile and difficult to handle.

The operating range of Cartesian Robots is simple and easy to understand compared to, for example, robots with 6-axis motion, and the price is favorable. Cartesian Coordinate Robots can be used stably even under severe conditions, such as in humid places or semiconductor factories where corrosive gases are used.

Principle of Cartesian Robots

The basic operation of Cartesian Robots is to slide a work arm along a linear guide to perform tasks such as assembly, transportation, and positioning.

Multiple units that move on a single axis are combined to perform work in a Cartesian coordinate system. In this case, since each axis of the robot can be moved simultaneously, many operations can be performed efficiently by superimposing linear movements.

Features of Cartesian Robots

1. High Degree of Freedom in Combination

Cartesian Robots have a relatively narrow operating range, but they can be combined with a high degree of freedom and can be easily adapted to the required specifications. Since their movements are simpler than those of other robots, they are easier to control, and it is possible to combine multiple Cartesian Robots.

By combining and coordinating with other robots, it is possible to perform many tasks, such as making some complex movements or incorporating processes such as material cutting

2. High Accuracy

Cartesian Robots can only perform simple linear movements, but the accuracy is higher. In particular, those using linear guides with ball screws and linear encoders can achieve highly accurate positioning.

3. High Rigidity

Cartesian Robots have fewer parts, which makes them more rigid. As a result, gaps and deformation are minimized, motion blur is reduced, and work is stabilized. In addition, the simple structure of the Cartesian coordinate robot allows for faster speeds and shorter cycle times.

4. Low Cost

Cartesian Robots, which can be manufactured with a simple structure and a small number of parts, are less expensive than articulated robots.

Other Information on Cartesian Robots

1. Disadvantages of Cartesian Robots

Cartesian Robots have disadvantages as well as advantages.

Complex work is impossible
It is difficult to perform complex tasks other than the combination of linear motion.

Large footprint
The disadvantage of Cartesian Robots is  that they tend to have a large footprint because they can only move in a straight line and cannot be folded because they have no joints.

Difficult to enlarge
It is difficult to make Cartesian Robots larger in size while maintaining their accuracy and strength, due to cost.

2. Examples of Cartesian Robots

Manpower saving in conveyance work
Although an articulated robot was used to automate the conveyance of change after packaging, a durability problem arose. Cartesian Robots were adopted for this improvement, and good results were obtained. The risk of breakdowns was reduced and labor productivity increased by 1.4 times.

Automation of Nail Brush Manufacturing Process
Nail brushes were mostly handmade due to the complexity of the production process. In order to reduce the aging of workers and costs, six Cartesian Robots were introduced, and the cutting, temporary attaching, and gluing processes were performed by the robots. As a result, six workers were reduced to two, and labor productivity has increased 30 times compared to before the introduction of the robots.

Reduction of Burden and Efficiency of Hazardous Work
Cartesian Robots were used to replace heavy and potentially hazardous tasks that were being handled by humans. As a result, hazards were eliminated, efficiency was improved, and labor productivity was increased 1.4 times compared to the previous system.

What Is a Rotary Table?

A Rotary Table is a rotating platform on which a device or object is mounted.

Rotary Table is used to rotate an object mounted on it to a desired orientation or angle, for positioning, or for measurement. The method of rotation can be manual or motorized. The control method can be open-loop or feedback control, and the size can be large or small, so it is important to select the right one depending on the application.

In addition, rotary tables are rarely used by themselves, as rotary motion is often accompanied by some subsequent operation, such as processing or measurement.

Rotary Table Applications

Rotary Tables are used to hold semiconductor wafers for inspection, precision measurement, and motion simulation. They are also used for precision measurement by fixing optomechanical components.

The Rotary Table itself can be mounted in a variety of orientations. It is used after considering whether it is more efficient to rotate the object to be processed or measured or the mechanical parts of the equipment.

High precision is required depending on the application: manual coarse rotation is used when a rough angle is required, while fine rotation is used when fine angle adjustment is required.

Principle of Rotary Table

Rotary Table has a cross roller bearing structure, a sliding structure, and an angular bearing structure.

1. Cross Roller Bearing System

A cross roller bearing consists of a roller race with a 90° V-groove and a cylindrical roller. The cylindrical rollers are arranged orthogonally and alternately with a contact angle of 45°. The back bearing structure in a ball bearing can be realized with a single row, enabling the bearing to receive loads from multiple directions simultaneously.

When the Rotary Table is driven, multiple cylindrical rollers roll on the roller race, which is characterized by almost no change in friction from stop to start. The cross roller bearing supports the load with linear contact and is a more rigid system than the ball guide mechanism. In addition, the rotary stage and cross roller bearing can be directly connected, which reduces the number of structural parts.

Since the rotational accuracy of the Rotary Table depends on the accuracy of the rollers, high rotational accuracy can be obtained depending on the accuracy grade of the rollers. In addition, since cross roller bearings have low frictional force and can be operated with light force, micrometer heads and other devices can be used in the fine rotation mechanism to obtain high positioning accuracy.

By connecting a stepping motor to the rotation mechanism, the angle and direction of rotation, as well as the operation procedure, can be automated.

2. Sliding Method

This is a sliding method in which one surface of the Rotary Table and one surface of the fixed side come into contact with each other. This is called dovetail sliding. The mechanism is simple, and dirt is difficult to get into the gap. Since the supporting area is large, it can withstand impact loads and large loads.

3. Angular Bearing System

Angular bearings are bearings with a contact angle to receive axial loads in one direction. When used in Rotary Table, two angular bearings are used and placed facing each other. This method provides greater rigidity for both axial and radial loads.

4. Motor-Driven

Stepping motors are often used for motorized Rotary Tables. The basic step angle is 0.36°, and the resolution is 0.004° at full step and around 0.0002° at microstep of 1/20 division.

Features of Rotary Table

1. Fine Movement Mechanism

In addition to the coarse rotation mechanism that allows 360° rotation, the Rotary Table is equipped with a fine rotation mechanism that allows fine rotation in a specific range. The fine movement rotation is performed by a worm and gear drive using a precision micrometer.

The range of fine rotation is generally ±3 to 5°. The resolution is about 5 arc-min on a vernier scale.

2. High Rigidity

The Rotary Table has very low deformation, wobble, and backlash. Axial wobble is generally less than 500 μrad.

3. Functionality

Some Rotary Tables can be used in Class 100 clean rooms. Many are also compliant with the European RoHS Directive. The coarse and fine rotation mechanisms can be locked by screws.

What Is Molding Machinery?

Molding machinery is machinery used in the molding of plastics and resins.

Specific uses include the manufacture of appliances and components. Extrusion machinery is used to produce tubes and rod products, molding machinery is used for styrene foam, and blow molding machinery is used for hollow products.

Molding machinery includes specialized machines for fluoroplastics, which are difficult to process, and vacuum molding machines, which mold under vacuum conditions, enabling high-precision molding. Molding machinery is suitable for mass production, but is now also used for small lot production.

For this reason, flexible molding machinery that can be switched in a short period of time has also been developed.

Uses of Molding Machinery

Molding machinery can mold a wide variety of materials, including plastics, metals, rubber, and ceramics. In the automotive and electrical/electronics industries, they can produce parts with complex shapes.

In the medical field, they are used in producing medical devices and prosthetics. They are also used in the construction industry to produce plastic exterior materials and roofing materials, in the food industry to produce chocolate and silicone molds, and in the textile industry to produce accessories and fabrics for spinning and weaving machines.

Principles of Molding Machinery

1. Injection Molding Machinery

Injection molding machinery consists of heating plastic raw materials and other materials, injecting them through an injection port, and placing them in a mold. In extrusion molding machinery, plastic materials are placed in a hopper, pushed out through an extrusion opening, and shaped by a mold.

2. Extrusion Molding Machinery

Molding machinery is a machine that extrudes thermoplastic materials by means of special mechanical pressure and heating. Plastic particles are fed from the machine’s feeder and melted by a heated screw.

The plastic material extruded at high pressure is then formed to fit the shape of the die, creating a shape. Finally, the formed product is cooled and separated by a cooling system.

3. Blow Molding Machinery

In blow molding machinery, plastic material is heated and placed into a hollow shaped die, which is inflated by air pressure to form the product. In molding machinery, thermoplastic resin is injected into the mold, cooled, and formed. In vacuum molding machinery, heated plastic film is applied to the mold under vacuum conditions.

Molding machinery performs molding operations in a high-temperature, high-pressure environment, so safety measures are important. In addition, factors that affect the quality of molded products include the type and quality of raw materials, mold design, and the adjustment of molding conditions. Molding machinery is suited for mass production, but today, flexible molding machines that can be switched in a short time are being developed to accommodate small-lot production.

Types of Molding Machinery

Molding machinery includes injection molding machinery, extrusion molding machinery, and blow molding machinery.

1. Injection Molding Machinery

Injection molding machinery is a machine that molds plastic material by injecting it into a mold. Injection molding machinery is characterized by its ability to mass produce at high speed. They are also highly automated, with operators simply operating the machine, which automatically performs everything from molding to ejection.

Injection molding machinery heats plastic material to melt it, and then injects the plastic through the injection port to form the mold. The plastic injected into the mold cools and hardens to form the desired shape.

Injection molding machinery is used for many products such as car panels, bumpers, computers, scissors handles, syringes, and smartphone covers. Mold design and manufacturing technology are important, as molds need to be designed according to the material and shape.

2. Extrusion Molding Machinery

Extrusion machinery is a machine that melts plastic, rubber, metal, or other materials and pressurizes and extrudes them to make tubes, sheets, profiles, pipes, and other shapes.

Plastic or resin is placed in the hopper, and the material is fed into the screw while adjusting the amount. The material is heated inside the screw to melt it and extrude it. At the end of extrusion, a mouthpiece called a die is attached to determine the shape.

3. Blow Molding Machinery

Blow molding machinery is a machine that uses air pressure to expand the material, which is then cooled and hardened as it is pushed into the die.

The temperature is raised to soften the material, which is then extruded through an extrusion screw to form a parison. The parison is cooled and molded by pressing it against the mold while blowing compressed air into it.

What Is an Air Shower?

An air shower is a box-shaped device installed at the entrance of a clean room, etc. It uses dust-free air filtered through a high purity multi-layer filter called HEPA to remove dust from people’s clothes.

Uses of Air Showers

Air showers are mainly used in semiconductor and precision equipment manufacturing facilities. In most cases, they are installed at the entrance to prevent dust from entering the clean room.

To maintain the cleanliness of the clean room, it is important to remove all the dust in the air shower. Because it can remove dust from clothes in a few tens of seconds, it is sometimes installed at the entrance of apartments for pollen allergic patients.

Principle of Air Showers

An air shower has a double door with an interlock that prevents both doors from opening at the same time. When a person enters the air shower from the outside, air is injected through the jets for a set number of seconds. The air is highly purified air that has passed through a HEPA filter.

This forces the dusty air to circulate and keeps the air shower space highly purified. Even when no one is in the room, the air is gently circulated to keep the air shower space constantly at a high level of cleanliness.

The interlocks on the double doors allow only a small amount of dust to enter when exiting, which also contributes to extending the life of the HEPA filter.

How to Choose an Air Shower

Select an air shower that meets the cleanliness requirements of the clean room, as higher dust removal performance is more expensive. Cleanliness of a clean room is classified by ISO based on the size and quantity of particles inside.

Each air shower is selected after confirming its guaranteed class. It is also possible to reduce costs by selecting a simple type of Air Shower that does not have a room. If the number of people coming in and out of the room is large or frequent, a large Air Shower that can accommodate several people at the same time may be selected.

Other Information on Air Showers

1. How to Use Air Showers

An air shower is a facility that removes dust to prevent dust from being brought into the clean room. However, if it is used improperly, it will not achieve the expected dust removal effect. First, decide on a standing position with a predetermined capacity, and mark the “stop” marker. Depending on the standing position, the air velocity hitting the body will decrease, and the dust removal effect will also be reduced.

Next, adjust the air outlet slightly downward toward the standing position. This has the effect of reducing the air blowing up and reducing re-contamination caused by the dust being blown up. During the air shower, rotate 2-3 times with your arms outstretched so that the air blows over your entire body. After rotation, the unit waits in place until the set time.

Generally, set the air shower time to about 30 seconds for one-sided blowers and about 20 seconds for two-sided blowers. 

2. Effects of Air Showers

An experiment was conducted to determine the correlation between the dust removal effect of an air shower and the time setting. In the experiment, the dust removal rate for each size was measured for 10, 20, and 30 seconds for the one-sided and two-sided types of air showers.

This experiment showed that the one-sided blowout type had a low removal rate of fine dust particles and was inferior in dust removal effectiveness. With the two-sided blowout type, the removal rate of each size of dust was almost equal, and the dust removal effect was high.

These results indicate that it is appropriate to select a double-sided blowout type for clean rooms that require high cleanliness. In places where cleanliness requirements are not high, it is more economical to use a single-sided blowing type to remove large dust and debris.

As for the dust removal time, experimental data for the two-sided blowout type shows that the dust removal effect is inferior at 10 s. Since there is no noticeable difference between 20 s and 30 s, it is generally recommended that the dust removal time be set at about 20 s. Since the dust removal effect of an air shower varies, depending on how it is used, it is necessary to ensure that it is used in an effective manner.

What Is a Positive Pressure Damper?

A positive pressure damper, also known as a differential pressure damper, relief damper, or barometric damper, is a device that regulates the internal pressure of a clean room to maintain positive pressure in the clean room.

By adjusting the differential pressure between the inside and the outside of the room, the positive pressure damper makes it possible to maintain a constant positive pressure inside a clean room.

Applications of Positive Pressure Damper

Positive pressure dampers are mainly installed in clean rooms to maintain a positive pressure inside the clean room that is one degree higher than the pressure outside the room.

They are also used in operating rooms.

Positive pressure dampers keep the room pressure higher than that outside the room, venting out only the amount of pressure that is higher than the specified value and closing the damper when outside pressure is applied to keep the room clean at all times.

Principle of Positive Pressure Damper

Positive pressure dampers are installed in ordinary clean rooms because it is necessary to keep the room at a positive pressure to prevent dust from entering from the outside.

One of the four principles for maintaining air cleanliness above a certain level is to “prevent the entry of contaminated air from the outside,” and for this purpose, the air inside the room must be kept at positive pressure (high pressure relative to the air outside the room).

On the other hand, if the pressure inside the room is too high compared to outside the room, it may cause adverse effects such as difficulty in opening and closing doors when entering and leaving the room.

Therefore, the opening door of the positive pressure damper opens and closes from time to time in response to the pressure difference with the air outside the room, making it possible to keep the air inside a clean room at a constant positive pressure.

Depending on the installation method, it is also possible to make the negative room pressure in the opposite direction.

In a clean room environment with strong pressure, the positive pressure damper may open and close frequently.

As a countermeasure, a weight can be attached to the back of the positive pressure damper’s open door to adjust the degree of opening.

Incidentally, the cleanliness of the air in a clean room is affected by the temperature, humidity, and cleanliness of the room, as well as internal heat generation, personnel in the room, local exhaust, and other factors that affect the capacity of the clean room air conditioning system.

There is also a damper with a fireproof shutter.

These dampers with fire shutters have a built-in thermal fuse that automatically closes the blades of the opening when the temperature rises above a certain level (72°C).

This allows the airflow between the damper and the point of fire to be blocked, preventing the spread of fire and the filling of toxic gases.

Variations for different applications are also available, such as X-ray protective types.

What Is a Circuit Breaker?

A circuit breaker is an electrical device capable of interrupting a circuit where an accidental current flows.

Circuit breakers for low voltage include wiring circuit breakers to detect overcurrents and ground leakage circuit breakers to detect leakage currents. Circuit breakers for high voltage are used in conjunction with protective relays because they are not equipped with accidental current detection functions.

Uses of Circuit Breakers

Wiring circuit breakers are also used as safety breakers in ordinary homes. Circuit Breaker is a device that interrupts a circuit in general, but the wiring circuit breaker installed in a home switchboard is called a safety circuit breaker.

The purpose of installing circuit breakers is to protect circuits and people from accidental currents, such as short circuits and ground faults. Since these can cause electric shock or fire, they are always installed in electrical products and switchboards.

Principle of Circuit Breaker

Wiring circuit breakers are generally of the thermodynamic electromagnetic type, utilizing the deformation of bimetal caused by overcurrents. When an overcurrent flows, the bimetal generates heat and deforms to release the latch, thereby breaking the circuit.

Thermodynamic electromagnetic wiring circuit breakers can be restored by manually returning the latch after the bimetal has cooled and returned to its original shape. RCD circuit breakers monitor the current in a circuit and interrupt it if there is a difference in traffic. If the circuit is properly insulated, the outgoing and incoming current values will be equal.

The difference between the outgoing and incoming currents is called leakage current, which is detected by the magnetic field of the zero-phase current transformer built into the RCD circuit breaker. Vacuum circuit breakers are mainly used for high-voltage circuits. Vacuumcircuit breakers are circuit breakers that turn off the arc by creating a vacuum at the opening and closing points of contact.

When a circuit with a current flowing through it is opened, a discharge phenomenon called an arc is generated. At high voltages, the arc discharge cannot be broken, and the contact point will burn up. Extinguishing the arc discharge is called quenching, and every high-voltage Circuit Breaker has a function that can quench high-voltage arc discharges.

Types of Circuit Breakers

Circuit breakers that protect against short-circuit currents of high-voltage or extra-high-voltage voltages have the function of quenching arcs, as mentioned above. Based on the arc quenching mechanism, the following types of circuit breakers are available. 

1. Aerial Circuit Breaker (ACB)

Low-voltage circuit breakers are generally used because they can be arc-quenched in the air without any problem. General low-voltage circuit breakers, such as safety breakers, are applicable to air circuit breakers . 

2. Gas Circuit Breaker (GCB)

A circuit breaker that quenches the arc by spraying an inert gas on the contacts when opening the circuit. Sulfur hexafluoride (SF6) gas is used as an inert gas, but because SF6 is a greenhouse gas, it is a circuit breaker that should be used with caution.

3. Oil Circuit Breaker (OCB)

A circuit breaker that quenches the arc using insulating oil. Since its dielectric strength is inferior to that of a vacuum, this type of circuit breaker is rarely used today. In the past, polychlorinated biphenyls (PCBs) were used as insulating oil, but the production of PCBs is now prohibited. 

4. Vacuum Circuit Breaker (VCB)

A circuit breaker that extinguishes an arc by creating a vacuum at the open/close contact point. Vacuum circuit breakers are the most common type of compact high-voltage circuit breaker. They have few actuators and are easy to maintain.

Other Information on Circuit Breakers

Difference Between Circuit Breakers and Breakers

There is no difference between circuit breakers and breakers. Breaker is an abbreviation for circuit breaker.

What Is Conveyance Equipment?

Conveyance equipment are devices that can automatically convey products between manufacturing processes instead of manually. They are used in various locations, including large factories, because they can move even heavy products safely and at low cost. The use of conveyor systems improves productivity and reduces human error.

There are various types of conveyor systems, including conveyor systems often used in manufacturing processes, automatic guided vehicles, and lifting equipment. The style of conveyor equipment is selected according to the product to be applied.

Applications of Conveyor Systems

There are various types of conveyor systems, and they are mainly used for conveyance between manufacturing processes.

Most heavy items, such as steel materials and automobiles, are manufactured using conveying equipment. In the food industry, conveyor-type transfer equipment is often used in factory production to maintain product cleanliness, moving products between processes without human intervention.

In the semiconductor industry, conveyor systems are often used to transfer semiconductors during processing while maintaining cleanliness in order to prevent contamination.

Principle of Conveyor Systems

There are various types of conveyor systems, and the principle differs depending on the type.

• Elevating Type
  The elevating type performs vertical unloading. There are simple lifts, elevators, and elevators. Since it is basically a transport device, most of them do not allow people to get in. Depending on the device, it may be necessary to check the Building Standard Law, Industrial Safety and Health Law, etc., for installation.
• Conveyor Type
  Conveyors use multiple rollers or belts. It is like a walking sidewalk. Simply place the product on the rotating rollers or belts of the conveyor and it is automatically conveyed. There are also pneumatic levitation conveyors in which the belt is supported by air to eliminate vibration.
• Unmanned Conveyor Vehicles
  This is a conveyance device in which magnetic tape or magnetic rods are installed on the floor, and a cart carrying a load is guided by the magnetism emitted from the magnetic tape, etc., so that it can proceed unmanned. It can also carry heavy objects such as molds. AGVs are also called AGVs, and are used in factories, hospitals, logistics sensors, and other facilities that operate 24 hours a day.