月: 2022年9月

What Is a Pipe Fitting?

A pipe fitting is a component used to connect different types of pipes.

It is one of the main methods of connecting pipes, but it also serves not only to extend pipes but also to change the direction of routes, branch or join pipes, enlarge or reduce the diameter of pipes, and seal the ends of pipes. Some pipe fittings are removable after connection, while others are not. In terms of ease of maintenance, it is recommended that removable pipe fittings be used for part of the piping.

It is very convenient to use both types of fittings, because while fixing the entire pipe increases its strength, doing so makes it impossible to replace only the faulty part. There are also various shapes, materials, and connection methods. It is necessary to select the appropriate pipe fitting according to the application of the fitting and the type and material of the piping.

Uses of Pipe Fittings

A pipe fitting is a component that connects pipes that transport gases and liquids. Therefore, a pipe fitting is used in facilities that use piping.

Specifically, they are used in water supply facilities, hot water supply facilities, drainage pipes, ventilation pipes, gas piping, fire prevention piping, cold and hot water circulation systems for air conditioning, agricultural water piping, chemical plant piping, and hydraulic piping. In addition to fluid piping, pipe fittings are also used for cable protection in the electric power and telecommunications fields, and are expected to improve construction work efficiency in the future as the use of utility poles is promoted.

Principle of Pipe Fittings

A pipe fitting is generally connected in two ways: flanged and screwed.

1. Flange Method

In the flange method, pipes are connected using a flange, which is a ring of two planes fixed to each other with a fitting in between. Since the fittings are secured to each other via the flanges and tightened with bolts, this method is characterized by high durability. 

2. Screw-in Method

The screw-in method connects pipes by making a cut at the end of the pipe, creating a spiral groove in the groove, and cutting a spiral groove that matches the end of the pipe to be connected. This method is simpler than the flange method and is used for relatively small pipes.

Types of Pipe Fittings

A pipe fitting has a wide variety of shapes and connection methods due to its extremely wide range of applications. In many cases, products from different manufacturers can be connected to each other, but it is important to check for compatibility before use.

The main types of Pipe Fitting are as follows:

• Socket
  Sockets are used to connect straight pipes of the same diameter with the same external threads.
• Nipple
  Connects straight pipes of the same diameter with the same internal thread.
• Coupling
  Directly connects straight pipes of the same diameter without threading.
• Elbow
  Used to bend the direction of piping. Bending angles include 45°, 90°, and 180°.
• Bend
  Used to bend the direction of piping. Compared to elbows, bends have a larger radius of curvature.
• Reducer
  Used to connect straight pipes of different diameters.
• Cheese
  Pipe Fitting with a T-shape to branch a pipe into a T-shape.
• Cross
  Pipe Fitting in the shape of a cross, which branches a pipe in four directions.
• Cap
  A cap is connected to a pipe by placing it over the pipe or by connecting it to the outer thread of the pipe to seal the end of the pipe.
• Plug
  A plug is connected to a pipe by fitting it into the pipe or connecting it to the inner thread of the pipe and sealing the end of the pipe.

Other Information on Pipe Fittings

1. How to Connect Pipe Fittings

Pipe fitting connection methods include threaded, welded, and flanged.

Threaded type
The pipe fitting is threaded, and the piping person threads it out for use. Since this connection method is removable, it is easy to repair and maintain.

Welded Type
The pipe fitting is inserted into the pipe and welded by insertion welding, or butt-welded by butt-welding the ends of the pipe and fitting against each other. This type of welding is stronger and more reliable than the screwed-in type.

Flange Type
Pipe flanges are connected with a bottle and nut.

Shafting Type
The pipe fitting is inserted into the pipe and welded by insertion is connected by wedging the sleeve of the pipe fitting into the pipe. When using a pipe fitting, the appropriate pipe fitting should be selected based on the shape, connection method, material, and size (pipe diameter) as described above. 

2. Threaded Sealing Material

When using a screw-in pipe fitting, a sealing material is required. Sealant prevents leakage from the joint. There are two types of sealing materials: liquid type and tape type.

In the case of screws, even when fastened, a gap exists between the outer and inner threads. The role of the sealant is to fill the gap at the screw.

What Is a Rare Earth Magnet?

Rare earth magnets are permanent magnets composed mainly of rare earth elements.

There are several rare earth magnets, including neodymium magnets, samarium cobalt magnets, praseodymium magnets, and samarium magnets. Rare earth magnets are characterized by their far superior magnetic properties compared to ferrite magnets.

Applications of Rare Earth Magnets

Rare earth magnets are used in many fields due to their small size and large magnetic force. Specifically, they are used in small magnetic sensors, small relays, small speakers, motor magnets, rotor parts, and rotor magnets in watches. In particular, the miniaturization of motors and other power sources has led to the miniaturization of products that use motors (e.g., robot arms). The use of rare earth magnets is expected to further advance in fields where product miniaturization and higher performance are required.

Characteristics of Rare Earth Magnets

Rare earth magnets are characterized by their magnetic strength. Compared to ferrite magnets and alnico magnets, rare earth magnets have far superior magnetic properties. Their magnetic force is more than six times stronger than that of ferrite magnets. The characteristics of rare earth magnets vary depending on the type of rare earth element they contain. Individual characteristics are described below:

• Neodymium Magnet

Neodymium magnets have the strongest magnetic force among rare earth magnets. The main raw materials are neodymium and iron. Since neodymium raw materials are relatively abundant, the cost is comparatively low among rare earth magnets. It is a rust-prone material and is thus usually plated or coated.

• Samarium Cobalt Magnet

Compared to neodymium magnets, the change (decrease) in magnetic force due to temperature is about 1/4 of that of neodymium magnets. It is suitable for maintaining stability at various temperatures, including high temperatures. Since it is a rust-resistant material, no plating or coating is required in normal use. It is a brittle material and care must be taken in its use and handling.

• Praseodymium Magnets

Praseodymium magnets are anisotropic rare earth magnets. It is characterized by high mechanical strength, with tensile strength more than three times that of neodymium magnets. There is no cracking or chipping. Machining is also relatively easy, and drilling and threading are possible.

What Is a Silver Oxide Battery?

Figure 1: Image of a Silver Oxide Battery

Silver oxide batteries, also known as SR batteries or silver-zinc batteries, utilize silver oxide and zinc as electrodes to deliver high energy density. This makes them ideal for compact, high-capacity applications like button batteries.

Applications of Silver Oxide Batteries

These batteries maintain a stable operating voltage, offering reliable power for precision instruments and medical devices, such as watches, hearing aids, cameras, and electronic thermometers. Their consistent performance is crucial for devices requiring accurate voltage, like quartz clocks and medical equipment.

Principle of Silver Oxide Batteries

Their operation is based on the chemical reactions between the silver(I) oxide positive electrode and zinc negative electrode, using potassium hydroxide or sodium hydroxide as the electrolyte. These reactions enable the generation of electricity with high efficiency and minimal environmental impact, as modern batteries are designed to be mercury-free.

Types of Silver Oxide Batteries

Varieties include small button cells and high-voltage stacked cells, differentiated by electrolyte type (potassium hydroxide as W type, sodium hydroxide as SW type) to suit specific applications. Advances in design have also focused on environmental safety and leakage prevention.

Other Information About Silver Oxide Batteries

1. Advantages

They offer high mechanical strength, low self-discharge rates, and excellent voltage stability, supporting a broad operating temperature range. Their energy density significantly surpasses that of lead-acid and alkaline button batteries.

2. Disadvantages

The primary drawbacks are their higher cost due to silver content, limited recharge cycles, and longer charging times compared to other battery types.

What Is a Lubricant?

A lubricant is a substance designed to reduce friction between moving parts, facilitate smooth movement, prevent wear, and dissipate heat generated from friction. It also serves as an anti-corrosion agent by forming a protective oil film on surfaces.

Lubricants range from liquids (lubricating oils) and semi-solids (grease) to solids (graphite, molybdenum disulfide, polytetrafluoroethylene [PTFE]), each suited to specific applications.

Applications of Lubricants

Lubricants play a critical role wherever parts move, from machinery to household items.

1. Liquid Lubricants

These are used in machinery like sewing machines, bicycles, and power tools for their ability to penetrate narrow gaps, facilitating smooth operation. They also serve as cutting oils in machining processes.

2. Semi-Solid Lubricants

Semi-solid forms, such as grease, are applied to components like shutters and gears during assembly for their non-permeable properties.

3. Solid Lubricants

Solid lubricants create durable films and are ideal for high-temperature environments or where maintenance is challenging.

Principle of Lubrication

Lubrication methods can be categorized into fluid lubrication, offering ideal conditions with minimal wear, and boundary lubrication, where direct contact between parts can lead to durability issues.

1. Fluid Lubrication

This method involves a thick oil film preventing direct contact between parts, significantly reducing friction and wear through the “wedge effect.”

2. Boundary Lubrication

Occurs when parts directly contact each other without a sufficient oil film, potentially causing galling or seizing, especially with similar metals.

Types of Lubricants

Lubricants are classified based on their state: liquid, semi-solid, and solid.

1. Liquid Lubricants

Includes cutting oils for metal processing and anti-corrosion/penetrating lubricants for loosening rusted components. Spindle oil, used for the smooth operation of machinery, and silicone-based oils for material slippage improvement are also common.

2. Semi-Solid Lubricants

Greases and compounds that contain thickeners to reduce wear and friction while providing rust prevention and lubrication.

3. Solid Lubricants

Materials like PTFE, molybdenum disulfide, and graphite offer low surface friction, high melting points, and resistance to seizing, suited for extreme conditions.

What Is a Pyroelectric Infrared Sensor?

Pyroelectric infrared sensors apply a physical phenomenon called the pyroelectric effect to infrared detection.

It is a sensor that detects heat generated from the human body or an object as infrared rays and captures the heat source.

The pyroelectric effect is a phenomenon in which polarization occurs inside a solid when heat is applied to ferroelectric material. Silicate minerals and tartaric acid are used as materials.

Pyroelectric infrared sensors have been adopted in many countries and are used as sensors in security alarms and motion detectors.

Applications of Pyroelectric Infrared Sensor

Pyroelectric infrared sensors are devices that detect infrared radiation emitted by heated objects, allowing them to identify the heat source, such as a person or object.

Compact, high-performance pyroelectric infrared sensors are widely used in a variety of situations where sensors are required.

There are many examples of the use of these sensors, mainly as intruder alarms for crime prevention and as motion-sensitive illuminators.

In recent years, pyroelectric infrared sensors have also been used in general households to detect people in air conditioning and heating equipment, televisions, and IoT devices.

Principle of Pyroelectric Infrared Sensor

The pyroelectric effect is a phenomenon in which an electric charge is generated by the polarization of molecules on the surface of a dielectric crystal when it is heated.

As the temperature rises, the polarization inside the dielectric responds immediately, and the constituent molecules respond as the polarization relaxes.

However, surface charges cannot respond as immediately as molecular polarization. Charges appear on the surface of the dielectric only as the polarization relaxes.

When a high-impedance load is connected to the electrodes on both sides of the dielectric, a current flows between the electrodes (called pyroelectric current). This pyroelectric current is used to detect the charge generated on the surface.

Since the pyroelectric current is generated when a temperature change occurs, it functions as a sensor when external thermal energy is applied.

Infrared light emitted from an external heat source is focused onto the sensor by an optical lens called a Fresnel lens. Optical filters are also used to avoid the effects of sunlight and illumination.

The output from the sensor is transmitted through an amplifier to increase the signal strength, which is then detected as a waveform.

What Is a Signal Relay?

Signal relays are components for electric circuits that turn on and off electrical signals of relatively low current.

Products that open and close signals of about 2A or less are common.

Uses of Signal Relays

Signal relays are used to switch electrical signals on and off. They are used in products that have electric circuits and have a wide range of applications, from home appliances to industrial equipment.

Specific applications are as follows:

• Home-use TV remote controls
• Inside control boards used in air conditioners and refrigeration units
• Inside control boards for hot water heaters
• Inside control boards for industrial robots
• Inside control boards for PCs

Mainly used by mounting on control boards. However, some products are available with an optional dedicated socket for mounting on the DIN rail of the control panel.

Principle of Signal Relays

Signal relays consist of a casing, input/output terminals, insulating parts, and contact switching parts.

1. Casing

The casing protects the signal relay. In most cases, it is made of resinous insulating material. It protects human contact with the electrical circuit. In some cases, simple specifications and serial numbers are printed on the casing. 

2. Input/Output Terminals

These are terminals for sending and receiving signals. Typical input/output terminals are in the form of pins, with multiple pins protruding from the signal relay. Terminals are inserted into special sockets or soldered to electrical circuits. 

3. Insulating Parts

These parts are used to support signals while insulating them. Generally, insulating materials such as resin are used because input/output circuits will be interfered with if supported by metal structures. The shape varies depending on the product. 

4. Contact Open/Close Components

These parts open and close contacts based on input signals. The construction of the component varies depending on the type of signal relay. In the case of a contact relay, it consists of a movable iron piece, a contact, an electromagnetic coil, and so on. In the case of non-contact relays, photo couplers and other parts are used as contact open/close parts.

Types of Signal Relays

Signal relays can be classified into two main types according to the type of contact point: contact relays and non-contact relays.

1. With-Contact Relays

Contact relays are relays that actually use electromagnetic coils and springs to open and close electrical contacts. They are also called mechanical relays. Generally, an electromagnetic coil is used to open and close the contacts by moving the movable iron strip to which the contacts are attached.

Silver, which has low electrical resistance, is used as the contact material. Products plated with soft gold to reduce contact resistance are also available. Since contact wear and deterioration of the moving parts occur, the relay is characterized by a life span that depends on the frequency of contact opening/closing.

2. Contactless Relay

A contactless relay is a relay that has no mechanical contacts. They are also called solid-state relays.

Contacts are opened and closed by semiconductor electronic components, such as MOSFETs. Since the contacts do not actually move, there is no residual life, depending on the frequency of contact opening and closing. Therefore, it has a longer life than a contact relay. However, the semiconductor components are sensitive to high temperatures and heat, making them unsuitable for use in high-temperature environments.

Other Information on Signal Relays

Contacts of Signal Relays

Relay contacts are divided into a-contact, b-contact, and c-contact. Each contact is used separately to configure a control circuit.

1. A-Contact
The A-contact is a contact that is open when no signal is input to the input terminal and conducts when a signal is input. It is also called a normally open contact or a make contact. It is the most common type of contact that provides signal isolation only.

2. B-Contact
The B-contact is a contact that conducts when no signal is input to the input terminal and opens when a signal is input. It is characterized by the opposite action of the A-contact and can invert the input signal. It is often used in interlock circuits and fault interrupting circuits.

3. C-Contact
The C-contact is a three-terminal contact combining a and b contacts. It has three terminals: a common terminal, an A-contact terminal, and a b-contact terminal. When no signal is input to the input terminal, the common B-contact terminal is conducting and the common-a contact terminal is open.

When a signal is input to the input terminal, the common terminal-B contact terminal is open and the common-a contact terminal is conducting. It is used for circuits that switch between forward and reverse rotation. Another feature of the C-contact is that it is applicable only to contact relays.

What Is a Mercury Lamp?

Mercury lamps are lamps that emit blue-white light using mercury vapor. Compared to incandescent lamps, mercury lamps have the advantages of higher luminous efficiency, longer life, and less maintenance.

Mercury lamps are broadly classified into two types based on the mercury vapor pressure at the time of lamp lighting: high-pressure and low-pressure. If the mercury vapor pressure is 10^5 Pa or higher, it is a high-pressure type, and if it is 100 Pa or lower, it is a low-pressure type.

Among high-pressure mercury lamps, there are also ultra-high-pressure types with mercury vapor pressures of 10^6 to several 10^7 Pa.

Uses of Mercury Lamps

Low-pressure mercury lamps are widely used as germicidal lamps because of their property of radiating ultraviolet (UV) light. Low-pressure mercury lamps may also be used as fluorescent lamps by coating the emission tubes with a fluorescent substance, in which case they are used for general lighting and as light sources for UV curing.

Typical applications for high-pressure mercury lamps include general lighting and UV curing. They are also sometimes used for photochemical reaction experiments.

There are two main types of super high-pressure mercury lamps: short-arc type and long-arc type. The former is used for optical microscopes and optical equipment due to its high luminance, while the latter is utilized for plate-making and semiconductor etching.

Principle of Mercury Lamps

Mercury lamps are designed to emit light by filling the light-emitting tube with mercury vapor and discharging the vapor into the mercury vapor.

When a discharge occurs in the light-emitting tube, mercury atoms in a low-energy state collide with electrons, resulting in a high-energy state (excited or ionized state). When the mercury atoms in this high-energy state return to their low-energy state, light equivalent to the difference in energy between the two is emitted.

The light emitted when the mercury ion returns to the mercury atom is called the continuous spectrum. The light emitted when the mercury ion returns from the excited state to the ground state (or metastable state) is called the emission line spectrum.

It is well known that the wavelength of light emitted by mercury lamps varies depending on the vapor pressure of mercury sealed in the light-emitting tube. Specifically, a low mercury vapor pressure strongly emits light with wavelengths in the ultraviolet region, while a high mercury vapor pressure increases light with wavelengths in the visible region.

In other words, low-pressure Mercury Lamps emit more ultraviolet light, making them suitable for sterilization lamp applications.

What Is Adhesive?

Adhesives are tools used to attach substances to substances.

Various types of adhesives vary in terms of the materials to be joined, the temperature at which they are used, and the time required for adhesive strength to develop after bonding. Therefore they should be selected according to the intended use. There are also various conditions under which adhesives cure, such as temperature conditions and the presence or absence of moisture or gas. In addition to the commonly known one-component adhesives, there are also two-component adhesives that can be bonded by mixing the main agent and curing agent.

Uses of Adhesives

A wide range of adhesives is sold, from low-viscosity and smooth ones to high-viscosity and vicious ones. Adhesives with low viscosity can, for example, be post-penetrating, meaning they penetrate through gaps in the threads after the screw has been secured.

Adhesives with high viscosity can be used not only to bond but also to block water and air from entering or leaving the area.

Adhesive Principle

Industrial joining includes screwing, riveting, and welding. Adhesives are used for joining plastic, soft materials, or materials that cannot be tapped by screwing or for joining at an angle. For metal-to-metal joints, welding is sometimes used in addition to adhesive bonding but at a higher cost. Adhesives have recently improved in performance, and a wide variety of adhesives are available for various applications, including those with bonding capabilities as strong as welding and anaerobic adhesives that begin bonding immediately after exposure to air.

Adhesion principles include mechanical bonding, chemical interaction, and physical interaction. Mechanical bonding occurs when the adhesive penetrates the pores and crevices of the material’s surface and cures there. Chemical interactions are formed by chemical reactions in which the adhesive and the object to be bonded share each other’s electrons (i.e. form covalent bonds between atoms). Physical bonding is referred to as intermolecular forces or van der Waals forces and occurs due to the intermolecular attraction that occurs when the adhesive and the object are brought closer together at the atomic level.

What Is an Operation Box?

An operation box, often referred to as a control box, switch box, cabinet box, or enclosure, is designed for housing and organizing control equipment and operating switches. These boxes facilitate the remote control of machines, devices, or equipment from a location separate from the main control panel.

Uses of Operation Boxes

Operation boxes serve a wide range of applications, including:

• FA control boxes and switch boxes for industrial control equipment.
• Breakers, control units, and pull boxes for electrical power equipment.
• Storage boxes for terminal block and equipment in factory settings, facilitating power connections to machine tools.
• Base stations and outdoor access points for telecommunications equipment.
• Connection boxes for solar power generation, outdoor measuring instruments, and communication equipment.

These boxes typically accommodate input and display devices such as pushbutton switches, selector switches, indicators, programmable displays, and panel computers.

Principle of Operation Boxes

An operation box includes a main body and a cover that opens via screws or hinges. It mounts control devices for input and display on the cover, allowing operation and visibility even when closed. Inside, a mounting board may be present for attaching additional control devices like control relays and terminal blocks. Cable glands and through holes facilitate the connection of control cables.

Types of Operation Boxes

1. Classification by Structure

Operation boxes vary by their opening mechanism—fixed or retractable—and may include locking features or hand grips for easy adjustment. The size selection depends on the internal components and required cable management.

2. Classification by Material

Materials range from steel, stainless steel, aluminum casting, to polycarbonate and polybutylene terephthalate resins. The choice depends on the application environment, including indoor/outdoor placement and the need for protection against the elements.

3. Protection and Explosion-Proof Types

Operation boxes are classified by dust and waterproof grades (IP Code) and explosion-proof construction for hazardous locations. Selection should match the environmental conditions.

Other Information on Operation Boxes

How to Install an Operation Box

Installation methods include wall-mounted, handheld, and stand types, chosen based on the operation location and user preference.

What Is a Microwave Absorber?

Radar absorbent material (RAM) is a material that absorbs incident radio waves and suppresses their reflection. It is also called a radio wave-absorbing material. The energy of incident radio waves is converted into heat energy and consumed.

Several types of Microwave Absorbers have different principles of absorbing radio waves depending on the material and shape. The frequency band that can be absorbed differs depending on the type. Therefore, it is necessary to select a Microwave Absorber that matches the application and design it appropriately.

Uses of Microwave Absorbers

The main applications of Microwave Absorbers include noise suppression for electronic devices such as communication equipment and home appliances, anti-reflection for ETC and radar, and evaluation facilities such as anechoic chambers. Microwave Absorbers with characteristics suited to each application are used.

For electronic equipment, a sheet type is used that can shield against specific frequencies emitted by the electronic equipment and can be incorporated into the electronic equipment. On the other hand, for evaluation facilities such as anechoic chambers, Microwave Absorbers in a three-dimensional pyramid shape are used, which have absorption characteristics over a wide frequency band.

Principles of Microwave Absorbers

There are several types of Microwave Absorbers depending on the principle of absorbing radio waves, and the three main types are resistive, inductive, and magnetic.

The resistive type absorbs the energy of radio waves by converting the induced current generated by the incident of radio waves on the conductor into heat energy by consuming it due to the conductor’s own resistance.

The dielectric type uses the resistance component of the carbon particles themselves and the capacitance component between the carbon particles by mixing carbon particles with a dielectric such as foamed polyethylene or rubber. When the incident radio wave is low frequency, almost no electric current is generated. However, as the frequency increases, the impedance of the capacitance component decreases, and an electric current flows. The higher the frequency, the lower the impedance of the capacitive element. The higher the frequency, the more current flows, consumed by the resistor and converted into heat energy to absorb the radio wave energy.

Dielectric types are available in pyramid or sheet forms, depending on their shape. The pyramid type can be designed to absorb a wide range of frequencies because the frequency band to be absorbed is determined not only by the material mixed in but also by its shape.

The magnetic type is made of ferrite or other magnetic materials molded into tile-like shapes, which absorb radio wave energy through magnetic loss. The magnetic type can provide absorption characteristics in the low-frequency band compared to the dielectric type. For this reason, Microwave Absorbers have a wide frequency range by combining dielectric and magnetic types.

Other absorbers have a phase difference of 180 degrees concerning the incident wave to cancel out the reflected wave.