月: 2022年12月

What Is a Conveyor Chain?

A conveyor chain is a critical component in conveyors, particularly those used in chain-type conveyors on production lines. Designed to meet high specifications for temperature tolerance, weight transfer, and durability, it operates in challenging conditions where belt conveyors are not suitable. Conveyor chains engage with gear-shaped parts called sprockets to facilitate the transportation of products.

Applications of Conveyor Chains

Conveyor chains are essential in environments requiring high load capacity, durability, and resistance to high temperatures, surpassing the capabilities of belt conveyors. Examples include:

1. ATC Chain/Tool Pot

Used in machining centers for storing and transporting specific tools to the spindle for exchange.

2. For Waste Incineration

Employed in waste incineration facilities to transport materials into incinerators, requiring chains with high wear resistance due to the harsh conditions.

Principle of Conveyor Chains

Operating on the same principle as roller chains, conveyor chains consist of short plates connected by pins, with rollers engaging sprockets to drive the chain. Smooth operation is ensured by a bush between the pin and roller, acting as a sliding bearing to absorb the load during sliding motions.

Conveyor Chain Structure

The structure of a conveyor chain includes:

1. Plate

Plates are subjected to tension from sprocket rotation, designed for toughness and resistance to fatigue from impact loads.

2. Pin

Pins support the load when the chain bends, requiring high shear and wear resistance.

3. Bush

Bushes absorb impacts between the chain and sprocket, necessitating toughness and wear resistance.

4. Roller

Rollers mitigate impacts with the sprocket, demanding resistance to impact and abrasion.

Types of Conveyor Chains

Conveyor chains are categorized by their shape into several types:

1. R Roller Type

The standard conveyor chain type, with rollers larger in diameter than the plate width, offering high versatility for various conveyors.

2. F Roller Type

An R roller type with a flange to prevent lateral vibration, suitable for smooth, inclined, and specific product conveyors.

3. S/M/N Roller Type

Distinguished by roller diameter sizes and pin diameter, these types are designed for specific applications like bucket elevators and flow conveyors, with a focus on shock and wear reduction.

What Is a Contact Pin?

A contact pin is a component used to connect electrical signals, consisting of crimp terminals. Contact pins are commonly employed in situations where soldering is challenging or when cable connections need to be made over the shortest possible distance for compactness. They are individually modularized, allowing for the replacement or reuse of each contact. There are various standards, and some types can connect directly to the circuit board.

Materials used for contact pins typically include brass, pure copper, and phosphor bronze, with gold-plated or tin-plated surfaces to prevent corrosion. Phosphor bronze offers greater flexibility, while pure copper is used for power supply applications.

Uses of Contact Pins

Contact pins find applications in various forms, including connections between wire cables and pin-socket type connector terminals in factory automation equipment and electronic devices.

They are also widely used in industrial settings, such as power connection terminals for evaluation boards for various ICs and modules, LAN boards for data communication, and control lines for aerospace industry equipment.

It is important to note that the shape and size of contact pins can vary depending on their intended use, so careful consideration is required when selecting the appropriate contact pins for a specific application.

Principles of Contact Pins

Contact pins, often referred to as contacts, come in two main types: male and female. Pin contacts are male, and socket contacts are female. Male contacts are also known as posts, while female contacts are referred to as housings.

When connecting to a circuit board, a connector that mates with the board, known as a post with a base, is used in conjunction with the housing. The contact pins connected to the wire cable establish electrical connections with the wiring on the board side via the connector.

Each contact pin is electrically connected to the cable through a crimp connection. The central part is the core wire section for crimping the core wire, while the outer part is the sheath section that is securely tightened along with the cable. The central part is also called the core wire barrel and is tightened together with the cable. The sheathed part is also known as the sheathed barrel.

A special crimping tool is used for crimping the contact pins to the cable, and the selection of the tool should be based on the size range of the pins.

What Is a Wheel Conveyor?

A wheel conveyor is a type of conveyor equipment designed to transport loads across a series of wheels. It’s selected based on the size of the material being conveyed, with options like the Soroban conveyor or the Corocon carrier. The Soroban conveyor uses wheels arranged like an abacus (Soroban), whereas the Corocon carrier has two lines of regularly spaced wheels.

Applications of Wheel Conveyors

Wheel conveyors are commonly utilized in factory production lines for transporting various goods, including corrugated cardboard, plastic cases, paper, and wooden boxes. These conveyors are ideal for items with flat and solid bottoms that won’t get caught between the wheels.

Principle of Wheel Conveyor

Wheel conveyors operate by rolling a series of wheels to transport a load. They can be slightly inclined to self-propulsion, with the incline depending on the material’s weight. For example, a 10 kg cardboard case might need a 4% incline, while a plastic case of the same weight requires a 2% incline.

Wheel conveyors are often compared to roller conveyors, which use lined-up rollers for transport. Roller conveyors can be either self-propelled or externally driven. They are versatile and commonly used alongside wheel conveyors. Wheel conveyors are preferred for their better rotation and lighter weight, making them suitable for smoothly conveying lightweight products.

What Is a Bronze Bar?

A bronze bar is a type of product made from molded copper metal, known for its high electrical and thermal conductivity. It’s commonly used in switchboards and distribution boards as a bus bar or ground bar. However, it’s susceptible to oxidation over time, forming a green oxide film, and may require surface treatments or coatings for protection.

Uses of Bronze Bars

Bronze bars are utilized in various sectors due to their conductivity and corrosion resistance:

1. Electrical Circuits

They are integral in electronic component manufacturing and power transmission lines, serving as efficient electrical pathways.

2. Building Materials

Used in roofing and exterior materials, especially in historic and architecturally significant buildings, for their aesthetic appeal and durability.

3. Financial Investment

As a precious metal, bronze bars are traded in markets and used as investment assets, with prices fluctuating based on economic trends.

Characteristics of Bronze Bars

Bronze bars feature low electrical resistance and are used for branching current in distribution panels. They vary in size according to current requirements and often require protective covering to ensure safety.

How to Select Bronze Bars

When selecting a bronze bar, consider these factors:

1. Intended Use

Determine the application, which will dictate the required shape and dimensions of the bar.

2. Shape and Size

Choose the appropriate shape and size, such as rectangular or cylindrical, based on the specific application needs.

3. Current Capacity

Consider the current capacity, which depends on the cross-sectional area. Larger areas allow more current flow but are heavier and more expensive.

4. Surface Treatment

Select suitable surface treatments like electroless nickel or tin plating for enhanced corrosion resistance and improved solderability in electrical applications. Tin plating is often utilized for bearing parts and electrical contacts.

What Is a Photomultiplier Tube?

A Photomultiplier Tube (PMT) is one of the most sensitive optical sensors capable of converting light (photons) into electricity.

It consists of a glass tube in a vacuum with an incident window, a photocathode, a dynode, and other components. The principle is based on the external photoelectric effect, a phenomenon in which electrons are emitted from the surface of a metal when light is irradiated on it in a vacuum.

Since even a single photon can be converted into a large electrical signal at high speed (10-9 seconds), photomultiplier tubes are used in electron microscopes, environmental analysis equipment, medical equipment, spectrophotometers, and spectral analysis equipment as photodetectors.

Applications of Photomultiplier Tubes

Photomultiplier Tubes are used as secondary electron detectors in electron microscopes and in photoanalytical instruments such as UV-visible spectrophotometers and emission spectrometers. They are also used in dust counters to measure particles in the air, in laser radar (LiDAR) to detect light scattered by suspended particles in the air, and in medical devices such as positron emission tomography (PET) and computed tomography (CT) used for cancer screening.

LiDAR provides a means of detecting the position and movement of objects around a vehicle and is also expected to be a key technology for fully automated driving. The Super-Kamiokande, the world’s most advanced facility for neutrino research, uses 13,000 20-inch diameter Photomultiplier Tubes to capture the Cherenkov light (light produced when electrons exceed the speed of light in water) generated in a 50,000 ton water tank.

Photomultiplier Tubes are extremely sensitive and are capable of converting faint light into a sufficient amount of electrical signals. On the other hand, they also have disadvantages, such as requiring high voltage for use and being prone to picking up noise caused by thermal electrons. Therefore, the power supply for Photomultiplier Tubes must have extremely low noise and high stability.

Photomultiplier Tube Principle

Figure 1. Basic structure of photomultiplier tubes

Photomultiplier Tubes are optical sensors that can detect light from a single photon and convert it into an electrical signal. Figure 1 shows the overall structure of a Photomultiplier Tube.

The glass tube in a vacuum state contains a window through which light enters, a photocathode that converts photons into electrons through the external photoelectric effect (the effect of electrons being emitted into a vacuum), a focusing electrode that collects the photoelectrons, a dynode with about 10 stages that multiplies secondary electrons, and an anode that generates an electronic signal. A DC voltage of about 1,000 V is applied to the entire area from the photocathode to the anode.

1. Window Material

Borosilicate glass, quartz glass, UV-transmitting glass, MgF2 crystal, etc. are used as window materials, depending on the wavelength region of the light, mainly on the short wavelength side.

2. Photocathode

Figure 2. Photocathode and external photoelectric effect (Image)

The photocathode forms a quantum efficient (photoelectron generation efficiency) active layer on the surface in contact with the high vacuum. In the visible region, bialkali metal photocathodes, multi-alkali metal photocathodes of three or more types with sensitivity up to the infrared region, alkali halide photocathodes for UV detection, and photocathodes using III-V compound semiconductors with high sensitivity in the UV to near infrared region have been developed.

3. Die Node

Figure 3. Structure and function of dynode (image)

Photoelectrons are accelerated by a focusing electrode and collected in a dynode. The dynode forms an active layer that increases the secondary electron emission ratio on a substrate metal such as nickel or stainless steel. Alkali metal-antimony (e.g., SbCs), beryllium oxide, and magnesium oxide are typically deposited on the layers.

When electrons strike the dynode, a large number of secondary electrons are emitted. The emitted secondary electrons collide with the next dynode, where more secondary electrons are emitted. This process is repeated until the number of electrons increases more than one million times, and is detected as a sufficient amount of electrical signal.

Other Information on Photomultiplier Tubes

Structure of Secondary Electron Multiplier

Various structures have been devised for the secondary electron multiplier, such as circular cage type, line focus type, box-and-grid type, fine mesh type, and metal channel type, depending on the arrangement and shape of the dynodes and other components.

For each structure, the optimum electrode design is made by electron orbital analysis. Electrons travel in a high vacuum, enabling fast time characteristic acquisition. The high sensitivity and fast response characteristics that count light as a grain are the reasons why PMTs are used at the forefront of the industry.

What Is a High Voltage Resistor?

A resistor is an electronic component that acts as a resistance in a circuit and can suppress the flow of electricity. High-voltage resistors are highly accurate resistors that can handle extremely high voltages on the order of kilovolts.

There are a variety of products available for various applications, including resistors that can handle resistance values of up to 100 omega.

They can handle high resistance values and narrow deviations, which can improve reliability and suppress circuit signal variations.

Applications for High Voltage Resistors

Resistors regulate the amount of electricity flowing through a circuit in the form of suppression or help the circuit operate properly. High-voltage resistors are suitable for equipment and applications with high-voltage circuits because they are resistors that can handle high voltages.

Major equipment and applications include high-voltage power supplies, X-ray power supplies, and various high-voltage devices such as printers, copiers, automobiles, air conditioners, lighting, electrostatic discharge, lasers, and power supplies for plasma displays.

Principles of High Voltage Resistors

Resistors are electronic components that can suppress the flow of electricity, but by using conductors with high resistivity as materials among conductors.

High-voltage resistors are specialized for high voltage among resistors, so the parts used can handle high voltage by maintaining high insulation properties.

Based on a substrate and insulator, the resistor consists of a resistive element, a protective coating to protect the element, an external electrode, and an internal electrode connected to the element.

Alumina insulators are mainly used for the insulators.
Each part of the resistor has a structure that can withstand high voltages, making the resistor as a whole capable of withstanding high voltages.
Since the terminal part is the connection point of the resistor and receives voltage and current, a structure and material that does not affect the characteristics of the resistive element are used.

In addition, there are patterns of resistive elements, forming shapes that can withstand high voltages such as solid, meander, and serpentine.

What Is a Proportional Counter?

A proportional counter tube is a type of radiation detector. It detects radiation by measuring the number of electrons (electric current), utilizing the fact that when energetic particles pass through a gas, the gas molecules become ionized, producing electrons.

Ionization chambers and GM (Geiger-Müller) counters are radiation detectors based on similar principles, but they differ in the magnitude of the voltage applied to measure the current. Ionization chambers operate at a lower voltage range than proportional counters, while GM counters operate at a higher voltage range than proportional counters.

Applications of Proportional Counters

Proportional counters detect radiation types such as X-rays, α-rays, β-rays, γ-rays, and neutrons, and measure radiation counts and energy. Due to their simple structure and relatively straightforward manufacturing process, they are often employed as detectors in academic research and other fields.

Typically, they are used to measure radiation dose in the air, particularly for neutron detection and β-ray contamination detection. Proportional counter tubes for X-rays are also occasionally integrated as detectors in X-ray fluorescence film thickness meters. These meters are used for non-contact measurements of plating thickness, among other applications, owing to their large incident window and higher efficiency compared to semiconductor detectors.

Principles of Proportional Counters

Proportional counter tubes are typically cylindrical aluminum vessels filled with a mixture of inert gases such as argon, helium, neon, methane, and butane. They operate by applying a high voltage to wires stretched inside the tube. The cylindrical vessel features an incident window through which radiation enters the tube.

When incident radiation passes through the gas, the gas along its path becomes ionized, producing electrons and cations. The electrons produced are referred to as primary electrons. These primary electrons get accelerated by the electric field within the tube and further ionize the gas, leading to a phenomenon known as “gas amplification,” in which the number of electrons increases significantly. The amplified electrons flow into the wire inside the tube and are detected as an electrical pulse.

Since the number of amplified electrons is proportional to the energy of the incident radiation, this detector is called a proportional counter tube. The amplification rate of electrons depends on the type of gas and the applied voltage. However, if the gas and voltage are known, the energy of the incident radiation can be measured.

An ionization chamber operates on a similar principle to the proportional counter but operates at a lower voltage and therefore does not amplify the gas. Consequently, proportional counters have the advantage of higher sensitivity compared to ionization chambers. However, proportional counters may not measure the number of primary electrons as accurately as an ionization chamber, and their energy resolution may be inferior.

What Is a Chemical-Resistant Glove?

A chemical-resistant glove is designed to offer high-level protection and resistance against chemicals, including acids and alkalis. Solvent-resistant gloves, a subset of chemical-resistant gloves, are specifically designed to shield hands from chemicals such as acids and alkalis.

These gloves provide protection against a wide range of chemicals, including ketones, salts, detergents, and alcohols. They come in two main types: disposable and reusable.

Gloves are available in various thicknesses, with thicker gloves offering greater resistance but potentially making fine-detail work more challenging. Material choice affects durability, abrasion resistance, and chemical resistance, while thickness varies. Therefore, the appropriate type should be selected based on the intended use and specific tasks.

Applications of Chemical-Resistant Gloves

Chemical-resistant gloves find applications across diverse industries, including chemicals, electronics, aerospace, automotive, life sciences, machinery, equipment, metal fabrication, recycling, waste disposal, and the manufacturing of transistors and semiconductors. Specific use cases include:

• Handling aerospace equipment and components
• Working with painting tools, including spray guns and robots
• Managing unexpected chemical leaks and spills
• Cleaning and maintaining equipment
• Conducting fitting, dismantling, and assembly operations
• Processing and producing petrochemical products
• Performing sampling, experiments, and tests
• Engaging in shipping operations
• Handling chemicals in applications such as glass etching, metal plating, dyeing, and chemical plants

Principles of Chemical-Resistant Gloves

The primary materials used in chemical-resistant gloves include natural rubber, nitrile rubber, chlorosulfonated polyethylene, and polyurethane.

Gloves made from these materials undergo permeation resistance tests against various acids and alkalis, such as ammonia, sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid. Additionally, they undergo swelling rate tests with organic solvents and oils, including ketones, ethers, chlorinated solvents, alcohols, and fats and oils, to assess their performance.

The results of the permeation test are typically evaluated in three levels, while the swelling rate test is evaluated in four levels to indicate the product’s performance.

Features of Chemical-Resistant Gloves by Material

1. Natural Rubber

Natural rubber gloves are resistant to oil and solvents, making them ideal for precision work.

2. Nitrile Rubber

Nitrile rubber gloves conform closely to the hand, allowing for detailed tasks. They have low tension, reducing hand fatigue even during extended use. Nitrile gloves, especially those with excellent static control, dust resistance, and ion control, are suitable for tasks in the electronics and semiconductor industries, as well as chemical processing.

Nitrile is also used in combination with natural rubber for enhanced chemical resistance, making these gloves highly resistant to chemicals such as fuel oil, lubricants, and acids. Some variants feature a diamond surface treatment to prevent slipping. They are commonly used in petrochemical, machinery assembly, aerospace, and chemical industries, as well as for industrial cleaning, heavy equipment assembly, and handling hazardous chemicals.

3. Chlorosulfonated Polyethylene

Chlorosulfonated polyethylene gloves exhibit excellent resistance to aging, ozone, weather, chemicals, abrasion, and acids/alkalis. However, they may have limited resistance to organic solvents.

4. Polyurethane

Polyurethane gloves are known for their abrasion resistance, flexibility, and ease of use. They are commonly employed in tasks such as assembling machine parts, gardening, DIY projects, fruit collection and sorting, packaging, and delivery. Some variants come with a cotton lining for added comfort.

What Is Packing Machinery?

Packing machinery wraps containers with PP bands at the end. Depending on the quantity, there are various types, such as manual, semi-automatic, and automatic. In the case of manual tightening, a fixing device made of resin or metal, called a band stopper, may be used.

The “PP” in PP band stands for polypropylene. The PP band has a mesh-like surface. It is wrapped around the packing equipment, tightened, and finally cut to secure the band to the equipment.

Uses of Packing Machinery

Packaging equipment is mainly used in the logistics and manufacturing industries. While manually tightening PP bands is cost-effective, if there is a high daily packing frequency, using packing machinery becomes very efficient.

In the manual method, after wrapping, the band can be cut while being tightened by pulling a lever, ensuring reliable packing. In the semi-automatic type, wrapping is done manually up to the wrapping point, and then tightening and cutting are done automatically after wrapping completion. The advantage is that wrapping timing can be controlled by sensor control.

Principles of Packing Machinery

A band stopper is used to stop the PP band manually. In contrast, when PP bands are stopped by packaging equipment, the PP band is cut to the required length and then welded. In other words, the surfaces of the PP bands are melted together. Packing machinery usually comes with a built-in heater, which heats and melts the PP band, welding it together.

Because of the welding principle in packing machinery, the accuracy of the welding process is affected by daily temperature fluctuations. If the heater temperature is low, the bands will not melt sufficiently to adhere. Conversely, if the heater is too hot, the band will not be fully welded and may come off. Packing machinery is designed to cut and weld PP bands instantly, so if the band’s surface is melted too much, it will peel off.

One drawback of welding is that it reduces strength. The tensile strength of a band stopper is about 1900 N, but when welded, the tensile strength is much lower, at approximately 1400 N.

What Is a Cam?

A cam is a mechanical component designed to change the type and direction of motion. It achieves this by transmitting motion to a driven section via a contactor. For instance, the rotational motion of a circular cam can be transformed into the vertical movement of a rod-shaped driven section. Known for its simple structure, a cam offers a long service life and requires low maintenance. It is also efficient and minimizes force transmission to other parts. Cams come in various shapes and sizes, each suited for specific applications.

Uses of Cams

Cams are widely used in machinery and devices where a change in motion direction is needed, such as in an engine exhaust valve. In gasoline-powered vehicles, cams facilitate the smooth expulsion of exhaust gases. They transform the rotational motion of the engine into the reciprocating motion of valves, controlling the opening and closing of the valves in a timely manner.

Principles of Cams

Cams, which come in various shapes, efficiently change the motion direction. The two primary types are flat cams and three-dimensional cams.

• Flat cams, such as straight plate cams and rotating plate cams, use a simple, flat structure. Straight plate cams transfer reciprocating motion to the driven section via a contoured surface, while rotating plate cams use an irregularly shaped plate to create vertical movement in the driven node.
• Three-dimensional cams, including cylindrical, spherical, and swash plate cams, have more complex structures. These cams use grooves or inclined surfaces to enable complex motion changes in the driven section.

Designing Cams

Designing cams involves selecting the appropriate type and mechanism. Key considerations include the cam type (plane or three-dimensional), the kind of driven installation (linear or oscillating), and the details of the output motion. Creating a timing diagram and considering factors like pressure angle and lever length are crucial. The pressure angle influences the load on the contact surface, and the cam’s diameter is determined based on the maximum pressure angle. Calculations for pressure angle, radius of curvature, and other parameters ensure the cam’s shape is optimal for its function. Finally, the design must account for surface pressure, mechanical strength, rolling contact fatigue life, and rigidity.

Confirmatory Cams

Positive-acting cams ensure reliable transmission of motion to the driven section. High-speed rotation may hinder the driven section from following the cam’s movement, so a spring is often used for constraint. Examples of positive cams include frontal, cylindrical, tapered, and spherical cams.