月: 2023年1月

What Is an Impact Wrench?

An Impact Wrench is a wrench that uses electricity or compressed air to tighten hex bolts. The word impact comes from the hammer mechanism inside the wrench, which applies an impact

Usage of Impact Wrench

Impact Wrenches are mostly used in production sites. Unlike human-powered wrenches, they can work at high speeds, so they are often used in factories and construction sites where many hexagonal bolts are used, and in automobile repair shops where tires are changed.

With the popularity of DIY, they are also used in ordinary households and are readily available at home centers and through mail order.

Principle of Impact Wrench

First, a motor is rotated by electricity, which rotates a built-in hammer, and the impact in the direction of rotation rotates a socket connected to the tip of the shaft, enabling fast and strong tightening and loosening of bolts and nuts.

The main parts of an impact wrench are the power unit, the drive unit, and the socket. 

1. Power Unit

The power unit is the driving force of impact wrench. A DC motor is mainly used for battery-powered wrenches and an AC motor for outlet-type wrenches.

2. Driving Unit

The drive unit is made of a spring or metal with a cylindrical groove cut in it, etc. When excessive torque is applied during rotation, the groove is removed and only the power part spins. This limits the torque and protects the power from overloading. 

3. Socket Part

The socket part is removable and can be used for multiple bolt sizes, which is a feature of impact wrenches. Some products can be used not only for bolts but also for impact drivers by replacing the socket.

Types of Impact Wrench

1. Difference in Power Source

There are two main types of power sources for impact wrenches: rechargeable type and AC power source type.

Rechargeable impact wrenches use batteries, so there are no cables, and they are suitable for sites that require easy handling. Although most of them are heavier for the battery, the battery type is preferred by many due to its mobility.

The battery voltage of 10.8V, 14.4V, 18V, and 36V are the main types of batteries. However, they are relatively less powerful. 18V and 36V machines have more power to tighten and loosen bolts, but they are also heavier.

AC-powered models are lighter than rechargeable models because they do not have batteries. Also, AC-powered models are often less expensive than rechargeable models, even if they have the same performance.

In situations where many bolts are to be tightened, work can continue for a long time without worrying about the battery running out. If there is an electrical outlet nearby or if you work without moving much, you can take advantage of the characteristics of the AC-powered type. 

2. Difference in Torque

Torque is the power to turn a bolt or nut when tightening or loosening it. How much torque can be tightened is indicated in Nm (Newton meter).

If the torque is too low for the work to be done, the motor will be overloaded, which may cause breakdowns. On the other hand, using too much torque may damage bolts and nuts. It is important to select a drive with full consideration of the conditions under which it will be used. 

3. Difference in Size of Square Drive

There are five standardized sizes of square drives to be attached to impact wrenches: 6.3sq, 9.5sq, 12.7sq, 19.0sq, and 25.4sq. They are not interchangeable, and you must have a socket that matches the size of each square drive.

Incidentally, as the size of the square drive for mounting the socket increases, so does the ability to tighten and loosen bolts of larger sizes.

Other Information on Impact Wrenches

Air Impact Wrench

There are air impact wrenches that are driven by compressed air delivered from a compressor. Compared to rechargeable or AC-powered electric impact wrenches, these wrenches are more powerful yet smaller, but because they require an air compressor, they are often used in factories and other locations where they are not moved very often.

What Is an Air Hoist?

An air hoist is a hoisting machine that uses an air motor instead of an electric motor to drive the hoist. Unlike electric motors, air hoists do not require concern for ignition or power supply voltage, making them safe for use in areas with ignition risks, such as chemical plants. Powered by compressed air, air hoists are primarily used for transporting lightweight workpieces. They offer adjustable speeds through push buttons, levers, or pull cords and are lighter and smaller than explosion-proof electric hoists of the same capacity.

There are two main types of air hoists: chain-based and wire-based. Generally, the chain type is preferred for heavier workpieces than those suited for the wire type.

Uses of Air Hoists

Since air hoists do not rely on electricity for operation, they are ideal for explosive environments like chemical plants, tunnel construction sites, mine shafts, and steel mills. They excel in production lines needing light workpiece handling or speed. Simple to operate, air hoists only require connecting to a compressed air hose. Compared to electric motors, they are lightweight, compact, and relatively easy to install, making them suitable for temporary or provisional production lines.

For horizontal movement, manual or air motor-driven trolleys transport products, parts, and equipment like luggage and jigs.

Principle of Air Hoists

An air hoist comprises an air motor, brake, reduction gear, control valve, operating equipment, safety devices, and trolley equipment.

1. Air Motor

The air motor, either rotary vane or radial piston type, serves as the driving source. The rotary vane type features a rotor within an eccentrically shaped cylinder, housing several radially movable vanes. The radial piston type incorporates pistons within star-shaped cylinders. Lubrication-free motors, which do not emit oil in the exhaust, require minimal maintenance, operating at compressed air pressures of about 0.4 to 0.6 MPa.

2. Brake

Brakes are essential for holding the load. A combination of an engine brake, leveraging the air motor’s characteristics, and a cone brake, linked to a control valve, provides strong braking force.

3. Reduction Gear

Compact and lightweight planetary differential gears, known for their large reduction ratios, reduce the air motor’s high speed to the winder’s speed.

4. Control Valve

A direct-acting spool valve, operable via a lever or pull string, allows for step-less speed adjustment.

5. Safety Devices

Certain models feature reverse winding prevention and overload stop devices.

Types of Air Hoists

Air hoists come in chain and wire rope variations.

1. Chain Type

Featuring a durable and tough chain, this type uses surface-hardened alloy steel load chains that can be extended.

2. Wire Rope Type

The lightweight wire rope type includes a reverse winding prevention device, automatically stopping the air motor when the rope is fully extended.

How to Choose Air Hoists

Air hoists, being smaller and lighter than electric chain hoists of equivalent capacity, perform well under challenging conditions such as extreme temperatures, high humidity, and explosive atmospheres. They eliminate the risk of motor coil burnout, even after prolonged use or inching. Speed adjustments are made by pressing or releasing a pendant-type pushbutton, allowing control over the hoisting and lowering speeds to match the task. Their mechanical brake construction ensures high durability and reliable braking force.

What Is an Air Pump?

An air pump is a device designed to intake air from one side and expel it from the other. It comes in various types, including motor-driven, voice coil motor (electromagnetic), and piezoelectric, all of which utilize a valve to separate air intake and exhaust. These pumps move a diaphragm to create continuous airflow, overcoming the traditional drawback of noise with recent advancements in silencer technology.

Uses of Air Pumps

Air pumps serve a broad spectrum of applications, from septic tank blowers and medical devices to bubble baths and industrial machinery. A common example is the aquarium filtration system, where the pump circulates water through filters to purify it before reintroducing the clean water into the tank, maintaining a clean environment for aquatic life.

Principle of Air Pumps

Air pumps operate based on the movement of a diaphragm influenced by a driving force, which could be a motor or piezoelectric element. This section explains the operational principles of different types of air pumps:

1. Motor Type Diaphragm Air Pump

This type converts motor rotation into diaphragm movement, creating a cycle of expansion and contraction within the pump housing to intake and exhaust air. A valve ensures unidirectional flow, preventing backflow.

2. Piezoelectric Diaphragm Air Pump

Piezoelectric elements induce diaphragm vibration, leading to volume changes within the housing that facilitate air intake and exhaust. This type typically produces a lower airflow rate due to the limited movement of the diaphragm.

3. Electromagnetic Air Pumps

Utilizing magnets or coils, these pumps employ alternating magnetic fields to drive pump action, commonly found in aquarium settings.

Types of Air Pumps

Air pumps are differentiated by their suitability for freshwater, saltwater, or both, with most modern pumps being versatile for dual use. They also vary by installation type: submersible, external, and amphibious. Indoor air pumps are designed to avoid exposure to environmental factors, whereas outdoor models are built to withstand conditions in garden ponds or external settings.

How to Choose Air Pumps

Unlike air filters, which primarily remove debris from water, air pumps focus on circulating water and air to maintain oxygen levels. For optimal aquarium health, a combination of an air filter and pump is recommended to ensure both clean water and adequate oxygen supply. Selection criteria for air pumps include discharge volume, durability, and operational noise, tailored to the user’s specific needs and budget.

What Is an Evaporator?

An evaporator is a device that evaporates a liquid or solid into a gas by reducing the pressure. When the heat of vaporization at this time is used, it is called a heat exchanger and is used in air conditioners and refrigerators. They are also used in distillation equipment to evaporate, collect, and remove solvents, as well as in vacuum evaporation equipment used to form thin films.

When used as heat exchangers, the media to be cooled are gases such as air and steam, and liquids such as water, brine, milk, and oil. The side to be cooled by heat of vaporization through decompression and evaporation is refrigerant, water, solvent liquid, etc. Heat is exchanged between the media on both sides.

Uses of Evaporators

Since evaporators are part of a system such as an air conditioning unit, they are used in combination with other equipment rather than alone. In air conditioners, evaporators are used to blow cold air into the interior of homes, automobiles, commercial air conditioners, etc. 

In the field of refrigeration and freezing, it is used to cool the interior of electric refrigerators, refrigerated freezer showcases, vending machines, refrigerator cars, and low-temperature warehouses. Industrial applications include chilling units and turbo chillers for producing chilled water, oil coolers for machine tools, and absorption chillers/heaters.

In the field of physical and chemical equipment, there are distillation units that are used to remove solvents. The inside of the equipment is depressurized by a vacuum pump to evaporate the solvent, and the gas is cooled and recovered. In the semiconductor field, evaporators are also used in vacuum evaporation equipment to form thin films on the surface of substrates by heating deposition materials such as metals and metal oxides in a vacuum and causing them to melt, evaporate, or sublimate.

Principle of Evaporators

When the pressure of a liquid or solid is reduced, the saturated vapor content decreases, and the liquid evaporates to become a gas. Evaporators are devices that actively utilize this effect to evaporate. In the case of solids, they evaporate and sublimate. In the field of refrigeration and air conditioning, fluorinated compounds, hydrocarbons, water, carbon dioxide, and ammonia are used as refrigerants.

When a liquid is evaporated in depressurized evaporators, the pressure rises as it is and the evaporation stops. For continuous evaporation, the evaporators must be connected to a device that lowers the pressure and circulates the liquid. An example of this device is a refrigeration-air conditioning cycle.

As an example, let us discuss a separate air conditioner for home use. The evaporators are the heat exchangers inside the indoor unit mounted on the wall of the room. The inside of the evaporators is depressurized, and the refrigerant evaporates to remove the heat of vaporization. The airflow from the blower is then cooled by the evaporators and blown into the room as cold air. The outdoor unit includes a compressor, condenser, blower, etc., and is connected to the indoor unit by piping to form a refrigeration-air conditioning cycle. The compressor sucks in the evaporated gas refrigerant from the evaporators and maintains the evaporators at low pressure. When the compressed refrigerant is cooled with outdoor air or water, it becomes a liquid. This heat exchanger is the condenser. The liquefied refrigerant circulates to the evaporators to continue the evaporative action. At the inlet of the evaporators, a throttling device such as an expansion valve or narrow tube is installed to serve as a boundary between the low-pressure and high-pressure sides.

What Is a Plastic Engineering Compound?

A plastic engineering compound is an engineering compound, which is a plastic with higher performance than the plastics used in everyday products.

When plastics were first developed, industrial equipment, production parts, and tools required a certain level of strength and heat resistance, which was difficult to achieve with plastics, so metals were used.

However, during the period of rapid economic growth, there was a growing demand for lightweight materials that could be easily processed, and plastic engineering compound with various functions were developed.

Uses of Plastic Engineering Compounds

Plastic engineering compounds are still very much in use today as product materials in various industries.

In the automotive industry, its applications include headlights, internal plastic parts, cylinders, gears, and connectors. They are also used in machinery, fans, impellers, and hydraulic tubes; and in the electrical industry, various cables, covering materials, sockets, and rotary switch parts.

The common point is that they are used in parts subject to severe wear and tear and are required to have various types of strength and heat resistance more than ordinary plastics.

Characteristics of Plastic Engineering Compounds

Plastic engineering compounds are characterized by higher strength and heat resistance than ordinary plastics.

Although there is no definition of what features plastic engineering compounds must exhibit, it must meet the following criteria: tensile strength of 40 MPa or higher and resistance to heat of 100°C or higher.

However, there is a standard that it can withstand a tensile strength of 40 MPa or higher and heat of 100°C or higher.

Plastic engineering compounds include polycarbonate, polyamide, polyacetal, and polybutylene terephthalate.

Super plastic engineering compounds, commonly known as super engineering compounds, are plastics that are stronger and more heat resistant than plastic engineering compounds.

Super plastic engineering compounds, commonly called “super plastic engineering compounds,” have a higher strength and higher heat resistance than plastic engineering compounds.

Like plastic engineering compounds, there is no clear definition, but they are generally defined as plastics with a heat resistance temperature of 150°C or higher.

Because of its increased strength and heat resistance, it is applied to parts that are subject to more intense wear and tear.

It is often used as a material for parts that accumulate damage on a daily basis, such as the inside of equipment, rather than for parts that are visible from the outside.

There are many types of plastic engineering compounds, and each has its advantages and disadvantages. However, they are all characterized by their high cost, so it is not necessary to use plastic engineering compounds when designing a product.

It is necessary to consider whether the product needs to be strong enough to use plastic engineering compounds when designing the product.

What Is an Autoclave?

An autoclave is a device that pressurizes and heats an object by blowing saturated steam into it.

An autoclave is primarily used as a sterilization process in molecular biology experiments because the high temperature and pressure of the steam can denature and effectively kill bacterial and microbial proteins. Handling autoclaves requires great care due to the use of steam at high temperatures and pressures.

As saturated steam is blown into the container, if the autoclave is used for industrial purposes on a large scale, it is subject to safety laws, and it is illegal to fail to report the use of the autoclave. The specific requirements are “a container” used at a gauge pressure of 0.1 MPa or higher with a content of 0.04m3 or more, or an autoclave with an inner diameter of 200mm or more for the body and a length of 1,000mm or more.

When using an autoclave that falls under this category, pre-use and annual inspections must be conducted.

Uses of Autoclaves

Autoclaves are mainly used as sterilization equipment in molecular biology experiments. In molecular biology experiments, flasks and petri dishes used to culture Escherichia coli and other bacteria, as well as tools used to handle bacteria, must be sterilized before reuse to prevent contamination by bacteria from previous use. For this sterilization process, autoclaves capable of heating to high temperatures are used.

In addition, genetic engineering experiments involve the use of genetically modified bacteria and cells that do not exist in the world. To prevent these from leaking outside the laboratory, not only reusable tools but also unwanted bacteria, and cell culture media. They are also used for solid media and must not be disposed of directly in trash bins or water sinks. Autoclaves are also used before the disposal of these bacteria.

In addition, the high temperature and pressure conditions of autoclaves can be used for special chemical reaction processes (Kolbe-Schmidt reaction, metal-catalyzed hydrogenation) and for molding plastics.

Principle of Autoclaves

The structure of autoclaves is similar to that of a pressure cooker. As with a pressure cooker, care must be taken in handling the amount of water to be put inside, opening and closing the lid, pressure relief valve, and so on. When water reaches 100°C or higher, it boils and vaporizes if the pressure is the same as atmospheric pressure.

However, if water is further heated to 100°C in an airtight container, the water hardly vaporizes and the temperature rises above 100°C. The internal pressure of the airtight container gradually rises above atmospheric pressure. A pressure cooker is a cookware that intentionally creates this condition to shorten cooking time. By placing moist food in a sealed container and placing it over heat, the water content rises to over 100°C and the food is cooked with more energy than boiling water.

Autoclaves also put moist intermediate products into a sealed container. In the case of autoclaves, the container will start on fire, but rather the internal pressure is increased by blowing in saturated steam. After the treatment process is completed, the pressure relief valve is opened to lower the internal pressure to about atmospheric pressure, and the treated product is removed. Since the energy that can be contained varies depending on the pressure of the saturated steam, the steam pressure is reduced according to the treatment process.

Other Information on Autoclaves

Heat Sterilization in Autoclaves

For contents to be autoclavable, use glass containers, glass flasks, glass Petri dishes, metal containers, and other items with excellent heat resistance. If plastic, rubber, fabric, or other items with low heat resistance temperatures are used, there is a risk that they will melt. Be sure to check the heat resistance temperature of the contents beforehand. Containers made of plastic or other materials must be sterilized by a method other than autoclaves.

When sterilizing glass flasks or glass Petri dishes used for culturing bacteria, etc., the autoclaves should be heated to 135-145°C for 3-5 hours, 160-170°C for 2-4 hours, 170-180°C for 1 hour, and 180-200°C for 30 minutes. Since water in autoclaves is subjected to high temperature and pressure during use, the amount of water and the strength of the lid closure must be thoroughly checked before operation to avoid accidents.

What Is a Gas Spring?

A gas spring, also known as a gas damper, gas pressure spring, or gas pressure damper, is a device that utilizes compressed nitrogen gas and oil within a sealed cylinder to exert a force in a specific direction—typically to push the piston rod out of the cylinder.

Due to their low spring constant, gas springs offer smooth operation with minimal force change over large strokes, making them maintenance-free. However, their reaction force may vary with temperature changes and could decrease over time due to the pressure of the enclosed gas.

Uses of Gas Springs

Gas springs find extensive use in automotive hatchbacks for opening and closing mechanisms. They are also employed in various applications such as doors of shelves and windows, supporting and holding the weight of the door in the open position. Their design often facilitates both opening and assisted closing. Beyond automotive use, gas springs are utilized in industrial equipment and office automation equipment.

Structure of Gas Springs

Gas springs are categorized based on their installation orientation: those that can be mounted in any direction and those with a limited installation angle, usually with a ±60° tolerance and the piston rod positioned lower. Despite the structural differences, the operational principle remains consistent across all types.

Principle of Gas Springs

Gas springs function by providing a nearly constant force over long strokes, facilitated by the differential pressure acting on the piston within the sealed cylinder. This pressure difference is achieved through the design of the piston and the specific arrangement of nitrogen gas and oil within the cylinder, allowing for smooth extension and retraction of the rod under controlled conditions.

Types of Gas Springs

Diverse gas spring types are tailored for specific functions and requirements:

1. Standard Type

These are designed for lifting or pushing down heavy objects, commonly found in equipment covers and car hoods.

2. Push-Open Type

Similar to the standard type but incorporates a mechanism allowing the spring to extend automatically when lightly pushed, useful in applications like retractable outlet taps.

3. Type With Lock

Locking gas springs are divided into rigid and elastic types, with the former locking securely at any position and the latter providing cushioning to absorb impacts, suitable for adjustable tables and office chairs respectively.

What Is a Gas Sterilizer?

Gas sterilizers are devices that utilize gas to eliminate microorganisms on medical devices, cosmetic containers, and other items requiring strict hygiene. Unlike methods that employ high-pressure steam or gamma radiation, gas sterilization is less likely to damage the items being sterilized.

The primary gases used in these sterilizers are ethylene oxide and hydrogen peroxide. Ethylene oxide gas sterilization is versatile and applicable to a wide range of materials, while hydrogen peroxide is favored for its lack of aeration requirement post-sterilization, making it efficient and safe for various applications.

Uses of Gas Sterilizers

Gas sterilizers are predominantly used in the medical sector for sterilizing reusable medical equipment and materials. These devices are preferred for items sensitive to heat, pressure, and moisture because they offer a gentler sterilization process. Outside the medical field, gas sterilizers are also employed for sterilizing temperature-sensitive plastic containers, such as those used in cosmetics.

Principle of Gas Sterilizers

Gas sterilizers, especially those using ethylene oxide, operate through controlled humidity and temperature conditions to maximize sterilization efficacy. Ethylene oxide is effective at room temperature and is non-corrosive to plastics and metals. The sterilization process involves maintaining specific temperature and humidity levels within the sterilizer and exposing items to ethylene oxide gas. This process requires careful management of conditions and a post-sterilization aeration phase to remove any residual gas, which is crucial due to the toxic and carcinogenic nature of ethylene oxide.

Features of Gas Sterilizers

The effectiveness of gas sterilization is influenced by factors such as gas concentration, humidity, temperature, exposure time, and the uniformity of gas dispersion within the sterilizer. Optimal conditions include a high concentration of ethylene oxide gas, sufficient humidity to facilitate the gas’s interaction with microorganisms, and a controlled temperature range to ensure effective sterilization without compromising the gas’s sterilizing properties. Additionally, ensuring uniform dispersion of the gas and adequate exposure time is critical for achieving thorough sterilization.

Preconditioning and the use of agitators within the sterilizer help achieve uniform humidity, temperature, and gas dispersion, ensuring effective sterilization across all items. The choice of packaging and loading method inside the sterilizer also plays a significant role in the uniformity of gas dispersion.

What Is Glass?

Glass is a substance composed primarily of silicon (element symbol: Si) and oxygen (element symbol: O).

The glass crystal is shaped like a tetrapod. This is called the tetrahedral structure, which consists of one silicon (Si) at the center and four oxygen (O) around it. Numerous such structures are linked together to form a substance made of silicon and oxygen.

Glass crystal is formed when these materials are linked vertically, horizontally, and laterally.

Uses of Glass

If you look around you, you will notice that glass is used in all kinds of places. In our daily lives, it would be rare to encounter a location in which we do not have glass products in our field of vision.

The primary application of glass is in window glass, which is also used in automobiles and trains. Other common uses include interior products, tableware, smartphone screens, and containers for liquids.

In this way, we live our lives benefiting from all kinds of glass products.

Characteristics of Glass

One of the reasons why glass has become so widely used is because of its manufacturing characteristics. The following are some of the characteristics of glass production:

1. Mass Production
   Glass is easily obtained in large quantities of high quality by simply melting and cooling the raw materials to obtain a uniform crystalline structure. Refining is easy and materials are readily available, making it suitable for mass production.
2. Trace Element Melting
   All kinds of trace elements can be contained in the glass structure. This makes it possible to produce tempered glass and a wide range of other products.
3. Workability After Molding
   Glass can be altered after molding, such as by grinding, polishing, and crystallization. For example, after refining, glass can be easily shaved to fit the shape of a window frame, making it easy to handle.
4. Deformability
   After being formed, glass is permanently deformable within the range of normal temperatures. Since its properties do not change at all with changes in temperature within the range of our daily lives, glass can be used for windows exposed to strong direct sunlight without any problems. On the other hand, it is also susceptible to breakage. However, with the advent of tempered glass, many products are now being sold that can withstand a certain degree of impact.

What Is a Tape Rule?

A tape rule, also known as a convex rule, is a measuring tool with a scale on thin metal tape. The term “convex” comes from the convex shape of the tape, allowing for greater rigidity and ease of use. 

Widely used by professionals and DIY enthusiasts, tape rules are essential for various tasks requiring measurement.

Uses of Tape Rules

Tape rules are primarily utilized in construction for woodworking, plastering, and in factories and offices. They are invaluable on construction sites.

While similar to tape measures made of cloth or vinyl, tape rules are designed for different purposes, such as measuring distances and lengths in more demanding environments.

Features of Tape Rules

Tape rules incorporate several features for ease of measurement. The “Zero Base Point Correction” allows for accurate measurements by compensating for the hook’s thickness. Additionally, a spring mechanism enables quick retraction of the tape, enhancing work efficiency.

How to Choose Tape Rules

With a wide range of products available from various manufacturers, selecting the right tape rule involves considering design, length, and material.

1. Length

Lengths vary from 1m to 10m. For general home use, a length of 3.5 to 5m is recommended, while 5 to 10m models are better suited for construction sites. Note that longer tapes are larger and typically more expensive.

2. Tape Width

Widths range from 6mm to 27mm, affecting the tape’s durability and ease of use. Wider tapes are more robust but heavier and bulkier, so choose based on your specific needs.

3. Scale

Some tape rules feature a dual scale, including both metric and traditional units, with some models having scales on both sides for convenience in marking. For home use, a metric scale may suffice.

4. Tape Material

Stainless Steel: Offers durability and rust resistance, ideal for use in moist or wet conditions.

Steel: Commonly used for its strength and affordability, though it may rust more easily than stainless steel.

5. Types of Coating Agents

Coatings such as acrylic, epoxy, polyester, nylon, dura, and silica offer various benefits, from abrasion resistance to improved visibility and durability in harsh environments.

6. Lock Function

A useful feature for measuring long distances alone, with different locking mechanisms available, including button lock, auto-lock, and W-lock for enhanced security.

Other Information on Tape Rules

Convex Standards

Tape rules adhere to various international standards, offering high precision. For tasks requiring accuracy, choosing a product that meets these standards is recommended.