カテゴリー: category_usa

What Is Silicone Oil?

Silicone oil, also known as silicone fluid, is a polymer composed of siloxane bonds, which are connections between silicon and oxygen. Renowned for its excellent heat resistance, weather resistance, and chemical stability, silicone oil maintains consistent viscosity despite temperature fluctuations. Due to its physiological inertness and harmlessness to the human body, it finds use in a range of industrial applications, such as machine lubricants, and consumer products like cosmetics and water-repellent clothing.

Available in various products with differing chemical structures and viscosities, silicone oil must be selected based on the specific application requirements.

Uses of Silicone Oil

Used extensively in manufacturing and industrial applications, silicone oil serves as an electrical insulating oil, lubricating oil, and anti-vibration oil. It’s also employed in cosmetics, anti-foaming agents, and water-repellent treatments for textiles and glass. Available in several types, each with unique chemical structures and viscosities, silicone oil is chemically stable and compatible with a wide range of materials due to its low reactivity with metals and other compounds.

Types of Silicone Oil

Silicone oil, a polymer linked by siloxane bonds between silicon and oxygen, varies based on the atoms or molecules attached to its side chain. Types include dimethyl silicone oil with a methyl group (CH3), methyl phenyl silicone oil with a benzene ring, and methyl hydrogen silicone oil with hydrogen in the side chain. Each type exhibits distinct chemical structures, thus leading to varied properties and applications.

Beyond standard silicone oil, modified varieties exist where the chemical structure of certain parts is altered, expanding its range of applications.

Characteristics of Silicone Oil

With robust siloxane bonds, silicone oil demonstrates exceptional heat and weather resistance and remarkable chemical stability. Its viscosity remains relatively constant across temperature changes, making it ideal for use in instrument oils and lubricants in the automotive and railway sectors.

Notable for its low surface tension, silicone oil readily spreads over various surfaces, unlike water or general synthetic oils. This unique property, among others, broadens its application scope significantly.

Safety of Silicone Oil

Physiologically inert, silicone oil poses minimal skin and eye irritation risks and is generally safe barring excessive ingestion. However, at temperatures above 150°C in an air atmosphere, it can produce minor quantities of harmful formaldehyde. While stable at high temperatures, certain silicone oils are classified as flammable liquids under the Fire Service Law, requiring careful management and storage in compliance with regulations.

What Is an Ion Exchange Resin?

Ion exchange resins are used to purify water. The surface of the resin is modified with sulfur groups and ammonium ions. When water flows through the resin, the ionic impurities in the water are exchanged with the ions on the surface of the resin, and the impurities are removed. Ion exchange resins are divided into two categories, cation exchange resins and anion exchange resins. They are used according to the type and strength of the ions to be removed. Ion exchange resins are used in a variety of applications, including the production of pure water and the removal of heavy metal ions.

Use of Ion Exchange Resins

Ion exchange resins are used to purify water. For example, seawater contains various ions such as salt, chlorine ions, and sodium ions. In addition, water used in factories may contain heavy metal ions. Ion exchange resins are used to remove these ions. Specific applications of ion exchange resins include the purification of pure water, processing of hard water with high calcium ion content into soft water, separation and recovery of heavy metal ions, and purification of pharmaceuticals.

Principle of Ion Exchange Resins

Ion exchange resins are spherical resins of about 0.5 mm in diameter with various functional groups modified on their surfaces. The modified portions exist in the form of ions and have a positive or negative charge. When water-containing ions flow through the resin, the ions in the water are exchanged with the ions in the resin depending on the strength of the ionic charge, i.e., the ions in the water are removed by the resin. Ion exchange resins can be divided into two types.

1. Cation Exchange Resins

Acidic functional groups are introduced on the surface of the resin to remove cations from water. Sulfo groups, which are strong acids, or carboxylic acid groups, which are weak acids, are modified on the surface of the resin, and the resin is used according to the strength of the ion to be removed.

2. Anion Exchange Resins

A basic functional group is introduced on the surface of the resin, which is used to remove anions from water. Ammonium ions and diethylamino groups are modified to remove anions such as chlorine ions.

Ion Exchange Resin Principle

The ability to remove ions depends on various conditions such as the ionic strength of the resin, the strength of the ions in the water, the concentration, and the column temperature. Therefore, optimization of conditions is essential for actual use.

Ion Exchange Resin Lifetime and Regeneration Methods

Ion exchange resins purify water by exchanging ions contained in functional groups modified on the resin surface with ions in the water. Therefore, as ion exchange resins continue to be used, the ions on the surface of the resin will continue to be replaced by ions in the water, and the ion exchange capacity will decrease.

However, ion exchange resins can be regenerated and reused. By immersing the cation exchange resin in hydrochloric acid and the anion exchange resin in sodium hydroxide, the ions in the water adsorbed on the ion exchange resin are exchanged with hydrogen ions from the hydrochloric acid and hydroxide ions from the sodium hydroxide. This allows the ion exchange resin to be regenerated and utilized.

Disposal of Ion Exchange Resins

Ion exchange resins can be regenerated and reused as described above. On the other hand, if the resin itself deteriorates, if the modified ion-exchange groups decompose, or if the ion-exchange groups are covered by contamination that accumulates on the resin surface, the resin cannot be regenerated.

When ion exchange resins are discarded after their performance has deteriorated to the point that they can no longer be used, they are generally incinerated. However, modified functional groups such as sulfo groups and chloride ions contained in water may decompose during incineration or change to oxides, which may cause air pollution. The disposal of ion exchange resins must comply with local government ordinances.

Pure Water Production Using Ion Exchange Resins

Ion exchange resins are used in pure water production equipment. However, ion exchange resins cannot remove impurities other than ions in the water. To remove such impurities, pure water production equipment includes sand and activated carbon in addition to ion exchange resins. First, sand filtration activated carbon treatment, and pre-treatment filters are used to remove impurities such as solids. After simple purification, pure water is produced by treatment with ion exchange resins.

What Is a Butterfly Valve?

A Butterfly Valve is a valve with a disk-shaped valve disc that rotates to control the opening and closing of the valve.

Butterfly valves are called “Butterfly Valves” because the shape of the valve disc resembles a butterfly. The valve can be used in small to large bore sizes, and if the valve interior is lined with PFA or other material, it can be used with corrosive fluids.

Also, compared to ball valves, the flow rate can be adjusted, and the pressure drop is lower than that of globe valves. However, they are difficult to use with high-pressure fluids.

Because they are easy to operate and inexpensive, butterfly valves are used in a wide variety of locations.

Uses of Butterfly Valves

Butterfly Valves are widely used in factory and plant piping, both manual and automatic. Butterfly Valves are not often seen in everyday life, but they are sometimes used upstream in water piping.

They are easy to operate, easy to open and close, and have a short face to face distance, so they can save space even in large bore sizes. For this reason, butterfly valves are often used in large bore locations upstream of transfer piping.

While general flow control valves have a large pressure drop even when fully open, Butterfly Valves have a small pressure drop and can adjust the flow rate to some extent. For this reason, butterfly valves are sometimes used as flow control valves.

Principle of Butterfly Valve

Butterfly Valve consists of a stem, a seat, and a plug. The stem is connected to a handle or other device, which moves the connected valve plug. The Butterfly Valve has a disk-shaped plug, which opens and closes by turning it 90° to close the seat. Compared to ball valves, butterfly valves feature low opening and closing torque and adjustable flow rate even in large bore valves.

Butterfly Valves used to be recognized as valves with low airtightness and prone to leakage. In recent years, EPDM and PTFE have been used for the seat material of the valve plug to ensure airtightness.

Butterfly Valve Opening/Closing Method (Gear Type, Lever Type)

To open and close the Butterfly Valve, an actuator must be attached to the end of the stem. A lever or gear is attached to the actuator.

1. Lever Type

A lever is used to open and close the Butterfly Valve. This is mainly employed for manual operation. The movement of the lever is synchronized with the movement of the shaft of the Butterfly Valve, and the valve is opened and closed by turning the lever 90 degrees.

It is simple to operate and the degree of opening can be easily visualized. However, the opening/closing operation becomes heavy for valves with large diameters. Because of the danger of unintentional contact with the lever that may change the degree of opening, the lever may be removed except during the open/close operation.

2. Gear Type

The opening and closing of Butterfly Valve is performed by gears. This type is mainly used for large-diameter valves. It may be motorized by a motor. In the gear type, a gear inside the actuator increases torque to move the stem. The large torque required for opening and closing is made possible with a small amount of force.

While the lever type requires only a 90-degree turn, the gear type requires multiple turns to open and close. Also, if left unattended for a long period of time, the gears may stick and fail to open or close.

In addition to the above, compressed air type actuators are also available and should be selected according to the application.

Other Information on Butterfly Valves

Wafer Type Butterfly Valve

Butterfly Valves and other valves can be connected to piping by flange, wafer, threaded, or welded connections. Wafer type valves are also called flangeless type valves and are connected by flanges on both sides of the valve.

The wafer type does not require a flange, making it compact, lightweight, and economically advantageous. In addition, the short distance between the faces enables installation in narrow spaces. It must be sandwiched between flanges on both sides and stud bolts are used.

Stud bolts are bolts that are threaded on both sides and are fastened by tightening nuts from both sides of the bolt. However, in emergency situations, stud bolts may be substituted with inch-cut bolts.

What Is a Bi-Metal Thermometer?

A Bi-Metal Thermometer is a measuring instrument that uses the properties of bimetal to measure temperature.

Bimetals are made by bonding two types of metal plates with different coefficients of thermal expansion, which bend as the temperature changes. This instrument uses the force of curvature to turn the axis of the needle that points to the scale on the display plate to directly read the measured temperature.

Compared to glass thermometers, it is more durable, easier to handle, and safer. Because of their simple structure and easy maintenance and inspection, bimetallic thermometers are widely used in household and industrial applications.

Uses of Bi-Metal Thermometers

Bi-Metal Thermometers are used indoors as wall-mounted or stationary thermometers. They mainly incorporate a spring-like bimetal to move the needle of a circular display plate with a printed scale.

Other applications include water thermometers, soil thermometers, and cooking thermometers.

The bimetal in the form of a spiral is incorporated in a protruding cylinder on the back side of the display plate. Furthermore, in industrial applications, bimetals are used for line temperature control in chemical plants, etc., due to their features of easy addition of waterproofness, corrosion resistance, chemical resistance, pressure resistance, etc.

Principle of Bi-Metal Thermometer

One of the bimetals is an alloy of iron and nickel, a low thermal expansion alloy whose thermal expansion coefficient is almost zero at around room temperature. The other is an alloy of manganese with chromium and copper, which has a very high coefficient of thermal expansion. Bimetal is manufactured as a single metal sheet by overlapping these two metal sheets and cold rolling.

Advanced technology is required for manufacturing bimetals, as their properties may change due to heat after prolonged use. When bimetal is heated, the alloy side with a large expansion coefficient is extended, so it warps with the low-thermal-expansion alloy side inside. Bi-Metal Thermometers have a mechanism that uses the force generated at this time to move the thermometer needle.

The actual structure is that the bimetal is wound around the thermometer in the form of a spring, and the pointer is rotated by twisting caused by temperature changes. The low thermal expansion alloy is called invar in and is a registered trademark. It is an alloy containing 64% iron, 36% nickel, and a trace of manganese. It is characterized by its low thermal expansion, which causes almost no thermal expansion of the crystal as a whole as temperature rises.

How to Install Bi-Metal Thermometer

If the product is dropped or subjected to excessive impact, deviations in readings will occur.

Therefore, it is necessary to install the thermometer while paying attention to the following points:

1. Vibration

Continuous vibration of the temperature-sensitive part will cause wear and tear on the thermometer’s components. Vibration of the temperature-sensitive part is observed as a small tremor of the pointer. In this case, appropriate measures should be taken immediately without leaving it unattended. 

2. Ambient Temperature

If there is a temperature difference between the ambient temperature and the object to be measured, the ambient temperature may cause measurement errors. It may be possible to improve the situation by keeping the equipment in use warm and suppressing heat dissipation and heat absorption.

3. Freezing Environment

When the temperature of the object to be measured is below the freezing point, the inside of the thermometer may freeze, resulting in damage to the product. If the product is to be used in a freezing environment, a dedicated product must be installed. In rare cases, a dedicated product may cause the inside of the product to freeze, but in many cases, this can be solved by selecting a product with special specifications, such as using a product with silicon oil.

Other Information on Bi-Metal Thermometers

1. Protective Tube for Bi-metal Thermometer

The following are cases in which a protective tube is required:

• When the object to be measured may corrode the thermosensitive part
• When high pressure is applied to the thermosensing part
• When the object to be measured is a fluid
• When the object to be measured leaks out and interferes with the thermometer when it is removed. 

2. Material of the Protection Tube

If the object to be measured is subject to corrosion, select a corrosion-resistant material for the protection tube. Also, if pressure is applied to the temperature-sensitive part, use a pressure-resistant material. 

3.Types of Protective Tubes

Types of protective tubes include nonferrous protective tubes, stainless steel welded protective tubes, and hollowed-out protective tubes. Selection should be made in consideration of the length of the temperature-sensitive part and other factors.

What Is Hydrogel?

Hydrogel is a general term for a solid such as a polymer that absorbs water and swells to form a non-flowable gel.

For example, when polymer chains such as polysaccharides and gelatin are cross-linked to form a three-dimensional network structure, the network structure contains a large amount of water and becomes a swollen body that cannot be dissolved in water. Examples include konjac, agar, and jelly.

Figure 1. Image of hydrogel

Uses of Hydrogel

Hydrogel is found in foods such as tofu and agar, and is also used in soft contact lenses and diaper absorbents (superabsorbent polymers). Because its composition is similar to that of biological soft tissue, its use as a medical material has been explored in recent years, but the loss of properties due to absorption of water in the body remains an issue to be resolved.

Examples include the use as artificial cartilage and artificial intervertebral discs, as a material that releases drugs slowly, and as a scaffold material for cells in the field of regenerative medicine.

After culturing cells on Hydrogel, only the gel is dissolved by a reducing agent to create cell sheets with cells attached to each other, which can then be applied to damaged areas for treatment.

Principles and Properties of Hydrogel

1. Physical Gel and Chemical Gel

Hydrogel is classified into physical gel and chemical gel according to the cross-linking method.

• Physical gel
  Cross-linked by hydrogen bonding, ionic bonding, coordination bonding, etc.
• Chemical gels
  Cross-linked by covalent bonding

As specific examples, items such as agar and gelatin, which undergo a reversible sol-gel transition when heated, are physical gels, while chemically stable items such as superabsorbent polymers used in disposable diapers and soft contact lenses are chemical gels.

2. Examples of Gelation

Figure 2. Example of gelation of sodium alginate

One well-known example is alginic acid, a natural polymer. The sodium salt of alginate is water soluble, but when a multivalent cation such as Ca2+ is added, ionic cross-linking occurs instantly. In this process, the solvent water is incorporated into the mesh structure of the cross-links, resulting in gelation (Hydrogel).

Types of Hydrogel

Figure 3. Conventional materials such as HEMA

HEMA (Hema: hydroxyethyl methacrylate) has been used in conventional soft contact lenses because it becomes soft when water is included. Since increasing the water content increases oxygen permeability, attempts have been made to increase the water content and to reduce the thickness of the lens. However, since a high water content rate causes water to evaporate more easily, the eyes tend to dry out during wear, and technological development has been considered to be limited.

Figure 4. The case of silicone hydrogel

Therefore, silicone hydrogel has been attracting attention in recent years as a new material that solves the HEMA issue. Silicone hydrogel is a material that exhibits high oxygen permeability despite its low water content. Since oxygen passes directly through the contact lens, it can deliver a large amount of oxygen without depending on the amount of water in the lens, which has the advantage of reducing the burden on the eyes.

It is expected to reduce the decrease in corneal endothelial cells in the cornea, which has been a problem with contact lenses in the past. Another advantage is that the low water content prevents the eyes from drying out while wearing the lenses. Furthermore, silicone hydrogel material is less likely to be contaminated by proteins contained in tears.

However, because it is highly lipophilic, once oil gets on it, it is difficult to remove. Therefore, care must be taken to prevent oil from adhering to eye makeup. The challenge is that it is a harder material than HEMA due to its low water content, and technological development is underway to improve its wearing comfort.

What Is a Notch Filter?

A notch filter is an optical filter that attenuates (blocks) light in a specific wavelength band to a very low level, while transmitting light in other wavelength bands at a high transmission rate.

Notch Filters are also called bandstops or bandpass filters. Generally, bandpass filters are used to transmit only light in a specific wavelength band, whereas notch filters do the opposite (blocking the transmission of light in a specific band).

Uses of Notch Filters

Notch Filters are used to remove excitation light from a single wavelength laser beam. A laser is generally a device that oscillates with an excitation light to produce high intensity and high power.

It emits light at a single wavelength, but the excitation light can be mixed in. Notch Filters can be used for the purpose of extracting the light emitted by the laser and blocking the excitation light.

Notch Filters are also used in Raman spectroscopy and fluorescence spectroscopy, which are analytical scientific instruments that use lasers. By cutting off the light from the excitation light source, etc., and detecting only the Raman spectrum or fluorescence spectrum to be measured, measurements with little background can be made.

Principle of Notch Filter

Notch Filters are made of a dielectric multilayer film, which are composed of multiple layers of dielectrics with different refractive indices, on an optically polished glass substrate.

The dielectric multilayer film does not absorb light, and the difference in refractive index between the layers causes reflection and interference, thus blocking light in a specific band. The transmittance varies depending on the angle of incidence and polarization (S or P polarization). The center wavelength of the blocked light shifts to shorter wavelengths as the angle of incidence increases.

Dielectric multilayer films are composed of materials with high refractive index (refractive index 2~2.5) such as titanium oxide and tantalum, and materials with low refractive index (1~1.5) such as silicon oxide and magnesium fluoride. These films can be deposited by vapor deposition in a vacuum or by electron beam deposition on a dielectric material.

The surface of the filter is very strong and scratch-resistant due to the dielectric multilayer film and anti-reflective AR coating, etc. It is possible to suppress performance degradation caused by time, temperature, and humidity, and to increase transmittance outside of a specific wavelength region.

In addition, the direction of incidence is determined and is generally indicated by an arrow-like mark on the edge of the filter. Whether the incidence is from the end of the arrow or along the arrow differs depending on the manufacturer, so it is necessary to confirm the direction of incidence in advance.

Other Information on Notch Filters

Terms Used to Describe the Performance of Notch Filters

The following terms are necessary to define the performance of Notch Filters in the selection:

1. Optical Density (OD) indicates how well a Notch Filter blocks laser light of a particular wavelength. 6 indicates transmission to the power of 10 minus 6, or 0.0001%, and the higher the OD value, the higher the blocking ratio.

However, the higher the OD value, the more optical it is and the wider the blocking area tends to be. Therefore, you can select a Notch Filter with an appropriate OD value by checking in advance how much you need to cut from the intensity of the laser to be used and knowing the OD value sufficient for blocking.

2. Center wavelength
The center wavelength is the wavelength at the center of the wavelength range where light does not penetrate the Notch Filter and where the OD value is the largest. Since the main purpose of notch filters is to block lasers, most commercially available notch filters are generally designed so that the center wavelength matches the wavelength of the most frequently used lasers. Some manufacturers produce Notch Filters with a specially selected center wavelength by special order, but they are more expensive than the commercially available ones.

3. Blocking region
The blocking region is the wavelength region where light is blocked by the Notch Filter. It is defined by the full width at half maximum of the region where no light is transmitted. Notch Filters generally have a high transmittance in the wavelength region outside the blocking region, and some filters have a transmittance that decreases as the wavelength region moves away from the blocking region. Therefore, when measuring a broad spectrum, it is necessary to check the transmittance spectrum in the measurement wavelength range in advance, because there is a problem that the target light cannot pass through the Notch Filter.

What Is a Needle Roller Bearing?

Needle Roller Bearings, also called are bearings in which the rolling element, the roller, is shaped like a needle. Needle rollers are long cylindrical rollers with a small outer diameter.

Uses of Needle Roller Bearings

Needle Roller Bearings are used in a wide variety of applications in general industrial machinery, automobiles, and many other places and in many different situations. Typical applications include connecting rods for engines and other internal combustion engines. Specialized models are also available.

Needle Roller Bearings, as mentioned above, have a small outer diameter, a large load capacity, and high rigidity compared to other bearings, allowing for a compact design.

Needle Roller Bearings are available in several types, each with different features and applications.

Principle of Needle Roller Bearings

Needle Roller Bearings, like other bearings, are available in radial and thrust versions.

The load applied to the bearing is radial load, which is applied in a radial direction perpendicular to the shaft (rotating shaft) center, and thrust load, which is applied in an axial direction parallel to the shaft (rotating shaft) center. Radial bearings are used when radial loads are applied, while thrust bearings are used when axial loads are applied.

Needle Roller Bearings feature linear contact between the needle rollers and the outer ring or inner ring of the raceway, which provides a larger contact area and lower stress on the contact surface compared to ball bearings.

The small outer diameter of needle rollers allows a large number of needle rollers to be placed in a single bearing, which saves space, increases rigidity, and accommodates high loads. In addition, their low mass and inertia allow them to be used in machines with oscillating motion.

Types of Needle Roller Bearings

There are many types of needle bearings.

Typical types are as follows:

1. Radial Bearings

Needle Roller Bearings with Cage

Needle Roller Bearings with Cages are bearings in which the cage (cage retainer) maintains the spacing between the needle rollers. The cage can be solid, punched, or welded. Needle rollers are available in single row or double row arrangements.

In this type of bearing, the needle rollers, which are the rolling elements, use the mating housing or shaft as the raceway, and there are no outer or inner rings, so the overall dimensions are small and space-saving installation is possible. However, the housing and shaft raceway surfaces with which the needle rollers come into contact must have a high degree of finish machining accuracy, high surface hardness, and sufficient hardening depth to prevent wear.

Caged Needle Roller Bearings are used in engines and transmissions for automobiles and other vehicles.

Shell Type Needle Roller Bearings

Shell Type Needle Roller Bearings consist of a thin steel plate drawn into a shell as an outer ring, a cage and needle rollers. The outer diameter is the smallest among bearings with outer rings, enabling space-saving installation.

The shell allows press-fitting into the embedded part, simplifying installation. Needle rollers are available in a single row arrangement or a double row arrangement. There is also an open-ended type with an open bearing end and a closed-ended type with a cover at one end.

The closed-end type can be used on the shaft end to prevent dust and other contaminants from entering the bearing. Shell Type Needle Roller Bearings are used in industrial machinery in general.

Solid Type Needle Roller Bearings

Solid Type Needle Roller Bearings consist of an outer ring, inner ring, cage and needle rollers machined from alloy steel. Some models have no inner ring and the needle rollers are in direct contact with a shaft or other raceway.

The outer ring is machined from alloy steel and has high rigidity as a bearing and high dimensional accuracy of outer diameter. Needle rollers are available in a single row arrangement or a double row arrangement. Solid Needle Roller Bearings are widely used in printing machinery, machine tools and general machinery.

Solid Type Needle Roller Bearings Separated Type

Solid Type Needle Roller Bearings Separated Type is a type of needle roller bearing in which the outer ring and inner ring can be separated from the needle roller (with cage) in the solid needle roller bearing described above. Each component can be separated and disassembled to simplify assembly. 

2. Self-Aligning Needle Roller Bearings

Self-aligning Needle Needle Roller Bearings have an alloy steel outer ring that is machined to have a spherical outer diameter and rotates inside the shell. Like shell bearings, they consist of a shell, outer ring, inner ring, cage and needle rollers.

However, unlike the shell bearing separate type, the shell, outer ring, and needle roller (with cage) cannot be separated.

In the case of the bearing with inner ring, the inner ring and the other parts can be separated as a single unit. This type of needle roller is applicable when the shaft deflection is large or centering is difficult. 

3.Clearance Adjustment Needlele Roller Bearings

Clearance adjustment needle roller bearings consist of an alloy steel outer ring with multiple grooves, a cylindrical inner ring, a cage, and needle rollers. As with self-aligning bearings, the outer ring and needle rollers (with cage) cannot be separated.

If an inner ring is provided, it is possible to separate the inner ring and the other parts as a single unit. When the outer ring is pressed in the axial direction (toward the center of the shaft axis), the inner diameter of the outer ring decreases and the clearance of the needle rollers can be adjusted.

Needle Roller Bearings with adjustable clearance are used for high speed and high rotational accuracy applications such as machine tool spindles.

4.Combined Type Needle Roller Bearings

Combined Needle Roller Bearings are bearings that combine the functions of both radial and thrust bearings. It is more compact and space-saving than installing both radial and thrust bearings.

Needle Bearings are used for radial loads, and Ball Bearings, Roller Bearings or Needle Bearings are used for thrust loads. Combined Needle-Bearings are used in machine tools and reduction gears.

5. Thrust Needle Bearing

A thrust needle bearing is a needle bearing used when a thrust load is applied. Like needle bearings with cages, thrust needle bearings are bearings in which the cage (cage retainer) maintains the spacing between the needle rollers. Special outer and inner rings are available and can be used as required.

The cage can be made of punched steel plate, aluminum alloy, or resin. Thrust needle bearings are used in machine tools and pumps.

6. Track Roller

Cam Followers
A cam follower is a bearing that incorporates a Needle Bearing (with cage), a Track Roller (outer ring), and a shaft (stud) on the inner ring side. The shaft protrudes on one side of the bearing only.

The track roller can be cylindrical or spherical in outer diameter. The cylindrical shape has a larger contact area, which is advantageous for high loads, while the spherical shape can tolerate a slight mounting error.

The shaft end is threaded and can be easily attached to the equipment with nuts. Cam followers are used when track rollers rotate and move on a track provided in equipment or facilities.

Roller Followers

A roller follower is a bearing consisting of Needle Bearing (with cage), Track Roller (outer ring) and Inner Ring. It differs from a cam follower in that it has an inner ring instead of a shaft, but is otherwise the same as a cam follower. There is also a model without inner ring.

What Are Nitrile Gloves?

Nitrile Gloves are gloves made of nitrile or synthetic rubber. Nitrile rubber is a copolymer of butadiene and acrylonitrile.

Compared to other rubber products, nitrile rubber gloves are oil and abrasion resistant, chemical resistant, and heat resistant.

Nitrile rubber products combine the advantages of long storage life. Another advantage is that, unlike natural rubber, they are less likely to cause allergic reactions.

Uses of Nitrile Gloves

Nitrile Gloves are used as protective equipment in a variety of locations. Specifically, their oil resistance is utilized in machine maintenance where machine oil is used, and in food factories where food oils and fats are present. They are also often used in medical and nursing care applications because of their chemical resistance.

Unlike polyethylene gloves, Nitrile Gloves are suitable for detailed work using fingertips because of their fit. Because of these characteristics, nitrile gloves are used in a wide variety of situations.

Principle of Nitrile Gloves

The acrylonitrile contained in the raw material nitrile rubber makes it highly resistant to oil. Increasing the amount of acrylonitrile has the disadvantage of lowering the cold resistance.

In many places, a well-balanced blend called medium-high nitrile is used. Nitrile Glove’s superior oil resistance makes it suitable for use as protective equipment.

In addition, Nitrile Gloves are highly damage resistant. Not only are they abrasion resistant, but they are also strong against punctures and tears. If damage does occur, it is easy to recognize the damaged area because it is widely spread out, and contamination can be avoided quickly. Thus, they can be used safely when handling hazardous materials.

What Is Nickel Plating?

Nickel is widely used as a plating metal because it is rust-resistant and chemically very stable. Nickel plating is often used to protect the surface of electrical components and decorative objects.

There are two main types of nickel-plating methods.

The first is called electro-nickel plating, which uses electricity to cause an oxidation reaction on the nickel anode and a reduction reaction to deposit nickel on the cathode (the material to be plated).

The second method is called electroless nickel plating, which uses chemicals instead of electricity to cause a chemical reaction to deposit nickel on the plated material.

Electrolytic nickel plating has a long history and was first developed in the 1830s. In Japan, the first nickel plating is said to have taken place in 1892. In the early days, electrolytic nickel plating did not have a shiny surface, and polishing was performed after the plating process to give it a shiny surface.

Principles, Types, and Uses of Different Nickel Plating Methods

Nickel plating methods include electrolytic nickel plating and electroless nickel plating.

Principles of Electro-Nickel Plating

Electrolytic nickel plating is a plating method in which electricity is passed through a solution to electrolyze nickel, the plating metal, causing a chemical reaction.

The plated object (material to be plated) is immersed in a nickel sulfate solution with the cathode and the nickel plate as the anode. When the nickel plate is energized, an oxidation reaction occurs and nickel ions dissolve into the solution, combining with electrons in the solution to cause a reduction reaction, depositing nickel on the surface of the plated material at the cathode and forming a film.

Types and Applications of Electrolytic Nickel Plating

Electrolytic nickel plating is used in a wide range of plating processes, from artistic to electrical components. There are three types of electrolytic nickel plating: bright nickel plating, semi-bright nickel plating, and matte nickel plating.

Typical applications for bright nickel plating include surface treatment of household electrical outlets and connectors.

Semi-bright nickel plating is mainly used for soldering and welding.

Matte nickel plating is less shiny and less attractive than bright nickel plating, but unlike bright nickel plating, it does not require additives to make it shiny. Therefore, a very stable and dense nickel plated film can be obtained without being affected by additives, making it suitable for plating internal components.

Principle of Electroless Nickel Plating

Electroless nickel plating is a method of forming a film on the surface of the plated object by depositing nickel through a chemical reaction between two chemicals in a plating solution.

The plated object is immersed in the plating solution. The plating solution consists of nickel sulfate, sodium hypophosphite, pH buffer, complexing agent, stabilizing agent, etc. Nickel ions in the plating solution cause a reduction reaction, depositing nickel on the surface of the plated object and forming a film.

About Nickel Chromium Plating

What Is Nickel-chrome Plating?

Nickel chrome plating is a silver-colored, slightly bluish-white plating often used for water faucets. Nickel-chrome plating is also known as decorative chrome plating. It is often used as a finish on top of nickel plating because of its good corrosion resistance, hardness, weather resistance, and good light and heat reflectivity.

Naturally, nickel-chrome plating is more resistant to impact and corrosion than nickel plating alone, and an oxide film forms on the surface of the chromium in the atmosphere, protecting the interior from corrosion while at the same time preserving its appearance.

Nickel-chromium plating is a treatment method widely used in addition to the above-mentioned water faucets, etc. because the luster of nickel plating combined with the silvery-white metallic appearance of nickel-chromium plating is popular as a decorative feature.

About Chromium

Chromium is classified into trivalent chromium and hexavalent chromium depending on the oxidation number. Hexavalent chromium is a substance whose use is prohibited by the RoHS and RoHS2 directives due to its reported environmental pollution and toxicity to the human body. Although plating with hexavalent chromium has been the mainstream plating process in the past, in recent years, due to its toxicity, plating with trivalent chromium has been widely used. The trivalent chromium plating process is superior in uniformity and has been developed to have the same corrosion resistance as the conventional process. In addition, it is a plating method that is harmless to the human body and easy to use in terms of workability, etc.

Corrosion of Electroless Nickel Plating

As a method to improve the resistance of nickel plated film to the salt air in the sea, etc., hypophosphite is used as a reducing agent during electroless nickel plating to deposit the plating.

This nickel plating film is called electroless nickel-phosphorus plating, but the major problem with this electroless nickel-phosphorus plating film is that the film is damaged in a short period when sea salt in the atmosphere is relatively low, leaving the metal bare and rusting.

Research has shown that when sulfate ions derived from sulfurous acid gas in the atmosphere come into contact with the surface nickel layer, a hydrate of nickel sulfate is formed, which is the substance responsible for the progressive corrosion of the surface nickel layer.

To address this issue, we have developed two-layer nickel plating (electrochemically protecting the underlying plating or material from corrosion by slowly oxidizing the upper plating layer) and three-layer nickel plating with bright nickel containing 0.1-0.2% sulfur in between the two-layer plating. In addition, the aforementioned nickel-chromium plating, etc. has also been developed. Nickel-chromium plating, as mentioned above, is also useful.

What Is a U-Bolt?

A U-bolt is a bolt used to secure a pipe to a trestle, bracket, or stay during a piping installation. The bolt is U-shaped and threaded at both ends, making it possible to easily and securely fasten a pipe with a single U-bolt.

JIS F3022, U-bolts for mounting steel pipes for ships, were previously used as the standard of U-bolts but were discontinued on August 10, 2006, due to its low frequency of use and limited track record. However, some products are still manufactured according to the old standard. Currently, specifications and dimensions are stipulated by each manufacturer.

Uses of U-Bolts

U-bolts are mainly used for fixing pipes. U-bolts are sized according to a pipe’s outside diameter, and the bolts are rounded and bent to follow accordingly, making them easy to fit on curved surfaces and provide good compatibility.

In addition to piping, U-bolts are also used for fastening leaf springs and axles in the rear suspension of heavy vehicles such as trucks and buses.

When the object to be fastened is rectangular, such as a square pipe or channeling, a square-shaped U-bolt is used instead of a rounded U-bolt.

Principle of U-Bolts

U-bolts, like normal bolts, use nuts to secure the object, but since the U-shaped bolt clamps the object, it is important to correctly measure the diameter of the object and select a bolt that is compatible with it.

When fixing a pipe in a piping application, the “nominal size” of the U-bolt is indicated by the pipe’s outer diameter (nominal or outer diameter), so a U-bolt with the same “nominal size” as the pipe outer diameter should be selected.
When using U-bolts for square pipes, select the “nominal size” of the U-bolt that indicates the required square pipe size.

If the member to which the pipe is to be fastened is thick, a foot-long U-bolt with a longer overall length should be used.
Since the JIS standard for U-bolts has been abolished, it is necessary to note that there may be variations with varying detailed dimensions among manufacturers.

Common materials for U-bolts include mild steel, austenitic stainless steel (SU304, SUS316, SUS316L), etc. Mild steel is available with surface treatment such as unichrome plating or hot dip zinc plating as a corrosion prevention measure. Select a material suitable for the application and operating environment.