月: 2023年6月

What Is a Pressure Increasing Valve?

A booster regulator is a pneumatic device used to increase the pressure of compressed air.

Generally, the pressure of compressed air used in facilities is about 1.0 MPa at the highest, but the pressure normally used is around 0.5 MPa.

When increasing the pressure used, it is necessary to change the pressure setting of the compressor when increasing the pressure of compressed air lines throughout a factory or business facility. However, if the pressure is to be increased for only a limited number of production lines or circuits, installing a pressure increasing valve at the inlet of the required location will serve that purpose.

In addition to this, a dedicated air compressor may be installed, or pneumatic drive may be used to select water, hydraulic oil, light oil, kerosene, or heavy oil for pressure intensification.

Uses of Pressure Increasing Valves

If the need arises to increase the pressure at a single point in the compressed air equipment used in a factory, increasing the pressure setting of the compressor will result in a significant increase in electricity costs. This is especially true for pressure resistance tests and air leakage inspections.

Some data indicate that lowering the set pressure of a compressor by 0.1 Mpa can lower electricity rates by about 7-8%. In such cases, installing a pressure increasing valve in front of the mechanical equipment that is under pressure is an effective means of reducing the pressure. By installing a pressure increasing valve, the pressure can be increased only where necessary.

Note that the flow rate of the increased pressure will decrease as the set pressure increases. Also, pressure increasing valves consume compressed air.

Principle of Pressure Increasing Valves

1. Pressure Increase Mechanism

The pressure increasing valve is operated by compressed air drive and requires no electricity. The pressure can be increased beyond the set pressure of the compressor. The difference between 2x and 4x pressure increasing valves is the internal structure.

In the case of 2x intensification, the structure consists of two cylinders of the same diameter, two intensification chambers, and two drive chambers. The cylinders of the drive chambers have pistons of the same diameter. The input pressure received by the two pistons then acts on the piston in one intensification chamber to increase the pressure.

The two pistons are connected by rods and synchronized. When the piston moves to the end of the cylinder, a sensor is activated, switching the pneumatic circuit so that the drive and intensification chambers are reversed and the intensification continues.

The construction of the quadruple intensifier is the same as that of the double intensifier, having two cylinders of different diameters, two intensification chambers, and a drive chamber. By making the total pressure-receiving area of the two pistons in the drive chamber four times larger than the pressure-receiving area of the one piston in the intensification chamber, 4-fold intensification is possible. Other operations are the same as in the case of 2-fold intensification.

2. Installation of Air Tank

For both 2X and 4X pressure boosting types, an air tank is generally installed to store pressure and prevent pulsation. The air tank is refilled to prevent pressure drop when pressure drops temporarily due to increased flow.

In addition, since the pressure increase is intermittent, it is effective in reducing pulsation. An additional benefit is a reduction in the intermittent operating noise of the pressure increasing valve. Compressed air contains oil and water, which must be discharged as they are separated when cooled in the air tank.

If the tank is not installed, insufficient flow will probably shorten the life of the pressure increasing valve, as it will be continuously driven.

Features of Pressure Increasing Valve

Advantage

• It requires no power source and is powered by compressed air.
• Compressed air pressure can be increased up to 2 to 4 times. The pressure can also be adjusted.
• Overall energy savings can be achieved by lowering the compressed air pressure for the entire plant and increasing pressure only where it is partially needed.

Disadvantage

• About half of the supplied air is exhausted, resulting in energy loss.
• It is common to install an air tank on the secondary side.
• Because of its intermittent operation, it has the disadvantage of being noisy.

Other Information on Pressure Increasing Valve

How to Use Pressure Increasing Valve

First, connect the supply air pipe to the IN side port and the air tank piping to the OUT side port.

After piping, supply air to the facility and adjust the pressure to the required level by turning the adjustment knob while checking the pressure gauge reading on the OUT side.

What Is Disposable Protective Clothing?

Disposable protective clothing is protective clothing intended for onetime use only.

It is worn over regular clothing, and the most appropriate type of clothing is used for each of the various uses of protective clothing. Conventional applications include training and exercises for the Self-Defense Forces, operational use, and treatment of infectious diseases in hospitals (e.g., H1N1 influenza, SARS, etc.). Infectious disease treatment in hospitals (e.g., H1N1 influenza, SARS), and so on. Recently, however, the need for use in the medical field in coronary disasters has been increasing, and availability has been decreasing.

Figure 1. Overview of protective clothing

Uses of Disposable Protective Clothing

Disposable protective clothing is used to protect workers from a variety of hazards in any workplace.

Hazards include acids, alkalis, chemicals, radioactive materials, and viruses. They also include sharp objects such as knives, high-speed flying objects, high temperatures, flames, and electrical sparks.

ISO/JIS standards provide detailed specifications depending on the characteristics of the clothing and the type of hazardous factor. Protective clothing for use in handling acids, alkalis, organic chemicals, other gases and liquids, and particulate chemicals. There are different types of protective clothing depending on the target hazardous substance and the structure of the chemical protective clothing, and the performance requirements are specified for each type.

Specific examples of disposable protective clothing include the following:

• Sites where skin may be exposed to or come in contact with acids, alkalis, organic chemicals, dust, or other hazardous chemicals, such as chemical plant construction
• Prevention of freezing when working in cold weather
• When working with asbestos
• Dioxin and PCB treatment
• Secondary infection control during treatment of new coronary infections
• Radioactive material handling and decontamination work
• Sites that need to cope with mechanical shocks such as chain saws

Types of Disposable Protective Clothing

Disposable protective clothing is classified into various types based on the uses of and materials used.

1. Classification by Use

Figure 2. Example of special protective clothing

Chemical Protective Clothing
Protective clothing is designed to prevent the penetration of toxic gases and chemicals. 

Protective Clothing for Biohazard Control
Protective clothing to protect against the risk of exposure to or contact with biohazardous materials (pathogens and biologically derived substances that may harm humans).

Protective Clothing Against Heat and Flame
Protective clothing is used to protect the body from heat and flames. Examples include smelters in the steel industry, where workers are exposed to high radiant heat and high-temperature molten metal splatter.

Protective Clothing to Cope With Mechanical Shocks
Protective clothing is used to prevent cuts and puncture wounds caused by sharp objects such as knives. As a specific example, at a site where chainsaws are used, the lower half of the body, below the thighs and knees, should be protected.

Protective Clothing Against Radioactive Contamination
Protective clothing is used for the purpose of protection against contamination by radioactive materials.

Protective Clothing Against Electricity
Clothing used to protect the body from electrical hazards, and protective clothing used to prevent electrostatic charging.

Protective Clothing Against Cold
Protective clothing is used to protect the body from the cold in areas or special locations where the outside temperature drops to negative temperatures.

High Visibility Safety Clothing
Protective clothing is used to increase visual recognition of the wearer’s presence in order to prevent contact and collision accidents caused by vehicles, construction equipment, and other moving objects.

2. Classification by Material

Figure 3. Various protective clothing materials

Non-woven Fabric One Layer Type
This product is made of spun bond polypropylene. The spun-bonded single-layer structure has many voids between fibers. Although the barrier property is somewhat inferior, it is inexpensive and suitable when cost is important. This fabric is sufficient for light soiling.

SMS
This product is made of SMS polypropylene. It has a three-layer structure of spun bond, melt blown, and spun bond. It features strong abrasion resistance and a cloth-like feel to the touch. Although relatively inexpensive, it is resistant to abrasion and light soiling, and has a high barrier effect against dust and splashes.

FS
This is a product in which film laminate is used. It has a structure in which a thin film material is attached to the surface of polypropylene, spun-bonded nonwoven fabric, or the like. It has high barrier properties against dirt and dust, and excellent waterproofing properties, making it suitable for work in watery areas.

Tyvek® (Japanese Brand of Polyester Foil)
Tyvek is a special material unique to DuPont, consisting of continuous microfibers of high-density polyethylene (0.5~10 microns) bonded together by heat and pressure, which provides excellent barrier properties against particles of 1 micron or less. Two-layer protective clothing with polymer coating is also available.

How to Choose Disposable Protective Clothing

As mentioned above, there are various types of protective clothing available, depending on the type of hazard. Work supervisors and personnel in charge of operations must acquire the correct knowledge of these hazards and protective clothing, and select protective clothing that matches the hazard. If used incorrectly, the possibility of health hazards increases.

In addition, if the knowledge is not sufficient, contaminated protective clothing may be taken outside the work area as it is, and there is a high risk of a secondary hazard if personnel other than those involved are exposed to the hazard. It is necessary to investigate the hazards in the surrounding environment, select appropriate protective clothing, and thoroughly educate workers on the correct way to use and put on and take off the clothing.

What Is a Disposable White Coat?

A disposable white coat (disposable lab coat, single-use lab coat) is a lab coat intended for onetime use only. It is worn over plain clothes, student uniforms, work clothes, suits, etc.

There are resin (polypropylene, vinyl, nylon, etc.) and cloth coats for various uses, and the most appropriate one is used depending on the intended use. Disposable white coats are used in high school and university chemistry experiments, hospitals (surgery, treatment of infectious diseases), and food processing sites.

Uses of Disposable White Coats

Uses of disposable white coats include:

• Experiments for students in high school and college chemistry experiments
• Treatment in the infectious disease ward of the hospital
• Dental treatments
• Father’s presence at birth
• Food processing plant
• Electronic component manufacturing site
• House mold removal work
• Spray painting work

Since there are different types of disposable white coats, it is important to choose the type that best suits the installation environment and the intended use.

Types of Disposable White Coats

There are two types of disposable white coats: plastic and cloth.

1. Disposable White Coat Made of Plastic

The greatest feature of this product is that it can be mass-produced in factories, although there is a possibility of allergic reactions when it comes into contact with the skin because it is made from chemicals. Since they can be mass-produced in factories, their cost is lower than that of fabrics, which is another attractive point. Although disposable lab coats cannot be reused, they can be recycled again as resin material through material recycling.

Currently, disposable white coats made of resin are the mainstream. From the perspective of the circular economy, it is desirable to use mainly disposable white coats made of resin, which can be turned in a closed loop.

2. Disposable White Coats Made of Cloth

It is ideal for people with sensitive skin, as it does not irritate the skin when worn. Also, because it is made of cloth, it can be washed and reused instead of being thrown away.

Other Information on Disposable White Coats

Advantages of Disposable White Coats

Prevent the Spread of Pathogens
In laboratories where microorganisms and bacteria are studied and in hospitals where infectious diseases are treated, discarding lab coats after each operation prevents pathogens from remaining in the laboratory or work area. When white coats are used for a variety of purposes, they must be carefully cleaned to keep them clean at all times, but inadequate cleaning may result in the presence of pathogens.
In addition, several people, including those involved in the cleaning process, may come into contact with contaminated lab coats. Using disposable white coats eliminates the risk of spreading pathogens from contaminated white coats and protects worker safety.

Prevent Worker Exposure to Chemicals
In places where chemicals are handled, wearing a lab coat can prevent workers’ clothes from being soiled by chemicals and prevent them from being exposed to chemicals on their skin, causing chemical wounds. However, the use of a disposable lab coat can cause the chemicals on the lab coat to permeate and harm the worker.
The use of disposable white coats eliminates the risk of wearing a chemically contaminated white coat, thereby reducing chemical injury to as close to zero as possible.

Prevent Cross-Contamination
Cross-contamination refers to the spread of contamination when an object that has become highly contaminated due to the attachment of pathogens or bacteria comes into contact with a less contaminated object. Cross-contamination is a serious problem in pharmaceutical manufacturing and food processing.
Using the same lab coat over and over not only increases the risk of cross-contamination by pathogens and bacteria, but also the detergent used to clean the lab coat and the lab coat fiber itself can cause cross-contamination. Disposable white coats are an effective means of eliminating these risks.

Hassle-Free
In places where contamination can lead to serious problems, the work environment must be kept at a high level of cleanliness at all times. As mentioned above, the risk of cross-contamination exists when white coats are used, so thorough cleaning and cleanliness control is required to prevent problems, which require time and effort to manage. By using disposable white coats, the cleanliness of white coats can be maintained at a high level at all times, eliminating the need for management.

What Is a Rotary Bar?

A rotary bar is the tip tool used when using a micro grinder.

It is used for cutting steel and other materials, chamfering, deburring, and shaping the cutting surface. It is highly versatile, capable of processing such as gentle curves. Because of its small size and fine machining capability, this tool is widely used in fields that require precise machining down to the smallest detail, such as in the manufacture of precision instruments and electronic components. It is also used as an easy-to-use tool among DIY and craft enthusiasts.

Uses of Rotary Bars

Rotary bars are used to cut general workpieces, nonferrous metals such as aluminum, brass, magnesium, and plastics, resins, and difficult-to-cut materials such as stainless steel, nickel, chromium, and titanium.

In particular, with the use of specialized blades, rotary bars can cut difficult-to-cut materials such as carbon fiber reinforced plastics (CFRP). They are also used for cutting with hand tools and robots.

Specific examples include cutting in the manufacturing process of automotive and aircraft parts. They are also used by DIY and craft enthusiasts when cutting or machining of small parts is required, and by selecting the blade shape to suit the uses of the application, a wide variety of machining is possible.

Rotary bars are indispensable tools in situations where precision cutting is required. By selecting a blade that is appropriate for the material and shape of the workpiece, an accurate and beautiful finish can be achieved.

Principle of Rotary Bars

A rotary bar removes material by applying cutting force to the workpiece through contact of a blade attached to a rotating bar.

There are several types of rotary bars, including cross cut, spiral cut, aluminum cut, and MC cut, and the blade type must be selected according to the uses of the bar.

The cross cut has low cutting resistance and minimizes mechanical vibration, enabling cutting of hard materials such as carbon steel and stainless steel. Spiral cuts help shorten cutting time because of their high cutting volume, and they eject needle chips. The aluminum cut has a blade shape that prevents welding of work pieces and is suitable for cutting aluminum and magnesium alloys. The MC-CUT has a small number of blades and is capable of rough machining.

Rotary bars also have specialized diamond-cut and other blade types, which are used for cutting difficult-to-cut materials such as carbon fiber-reinforced plastics. They are also used for cutting by hand tools and robots, and are widely used in various fields. By selecting the appropriate type for the cutting shape and material, more efficient and accurate cutting can be achieved.

Types of Rotary Bars

Two types of rotary bars should be used depending on the cutting shape and material: high-speed steel rotary bars and cabled rotary bars.

1. High Speed Steel Rotary Bar

Rotary bars made of high-speed steel (HSS) are commonly used to process metals and plastics, etc. Because of its relatively high hardness and resistance to temperature changes, HSS can be used for long periods of time without wearing out the cutting edges of high-speed rotating rotary bars. HSS rotary bars are also suitable for carving and other detailed work.

2. Carbide Rotary Bar

Rotary bars made of carbide (a hard alloy) are used to process hard materials such as metal and wood. Carbide is an alloy composed mainly of metals such as tungsten and tantalum, and has very high hardness. As a result, carbide rotary bars have a sharp cutting edge and can cut smoothly even through hard materials. However, they are relatively expensive and are not suitable for long-term use.

What Is a Hematocrit Capillary Tube?

A hematocrit capillary tube is an instrument used in blood testing.

Blood is composed of cellular components: blood cells (red blood cells involved in oxygen transport and white blood cells involved in the body’s immune defense) and platelets, and plasma, the liquid component that suspends these cellular components. In healthy human blood, the majority of cellular components are red blood cells. Red blood cells contain hemoglobin (Hb), which gives blood its red color and oxygen-binding capacity.

Plasma is composed primarily of water (about 93%), with other components including salts, various proteins, lipids, and sugars (e.g., glucose). The hematocrit, or the percentage of red blood cell volume in the blood, is sometimes determined during a blood test. For example, it can be used as an indicator of anemia. Anemia is a thinning of the blood, and hematocrit is used as an indicator of this condition.

The hematocrit capillary tube is the instrument used to measure this hematocrit.

Uses of Hematocrit Capillary Tubes

Hematocrit capillary tubes are primarily used to measure hematocrit in blood tests. It is also sometimes used to obtain small amounts of plasma in animal experiments.

1. Measurement of Hematocrits

Hematocrit measurements may be performed when anemia, dehydration, bleeding, or other medical or surgical conditions are suspected. A low hematocrit reflects a low number of circulating red blood cells and is an indicator of reduced oxygen-carrying capacity or overhydration.

Examples of conditions that can cause low hematocrit (anemia) include.

• Internal or external bleeding – hemorrhage
• Complications of Chronic Renal Failure – kidney disease
• Pernicious anemia – vitamin B12 deficiency
• Hemolysis – associated with transfusion reaction
• Autoimmune diseases and bone marrow failure

A high hematocrit may reflect an absolute increase in red blood cell count or a decrease in plasma volume.

• Severe dehydration – e.g., in cases of burns, diarrhea, or excessive diuretic use
• Erythrocyte Excess – erythrocyte Excess
• Viral polycythemia vera – abnormal increase in blood cells
• Hemochromatosis – inherited disorder of iron metabolism
• Indicators of overdose of exogenous erythropoietin (EPO), which stimulates red blood cell production

2. Animal Experiments

Because of its ability to collect very small amounts of blood and to obtain plasma by centrifugation, it is sometimes used to obtain minute amounts of plasma, mainly from animals (micro sampling).

Principle of Hematocrit Capillary Tubes

The most commonly used hematocrit capillary tube is a capillary tube (capillary tube) with a heparinized inner surface. Untreated (plain) capillaries are also available.

When one end of the capillary tube comes in contact with the collected blood, the blood is sucked into the capillary tube by capillary action. At the same time as the blood is sucked up, the heparinized blood is anticoagulated with heparin.

The capillary is then centrifuged to separate the blood cells from the plasma. The hematocrit is determined from the length of the blood cell portion (erythrocyte column), which appears red, and the plasma portion, which appears colorless to pale yellow (in humans).

Other Information on Hematocrit Capillary Tubes

1. Definition of Hematocrit

Hematocrit is defined as the ratio of red blood cell volume to total blood volume, also known as packed cell volume (PCV). When heparinized blood (heparin is an anticoagulant) is centrifuged, the red blood cells become packed at the bottom of the tube and the plasma remains as a clear liquid at the top. The ratio of this volume of packed red blood cells to the total blood volume is the hematocrit.

Hematocrit is reported as a percentage or ratio. In healthy adults it is about 40-48%, but in newborns it can reach 60%.

The following is a summary of the abbreviations associated with discussing hematocrit.

• Hct: Hematocrit
• ctHb: total hemoglobin concentration
• Red Blood Cell (RBC)
• MCV: Mean cell volume
• MCHC: mean corpuscular hemoglobin concentration

2. How to Use It When Measuring Hematocrit

Seal
One end of the capillary must be sealed before centrifugation. If not sealed, centrifugal force will cause the blood to flow out. To seal the capillary, a special putty is used.

After the blood is sucked up, one end of the capillary is sealed by sticking one end into the special putty and allowing the putty to bite into the inside of the capillary. The sealed side should face outward, i.e., toward which centrifugal force is applied.

Scale Plate
To obtain a hematocrit value from the centrifuged blood sample in the capillary tube, refer to the scale plate. Move the scale down the sample until the bottom of the packed red blood cell column first lines up with the “0” line on the scale plate, then the top of the plasma column lines up with the “100%” line.

At this point, read the values at the border between the red blood cell column and the plasma column. The white layer, the layer between the red blood cell and plasma columns, makes up about 1% of the sample, but this layer is not included on the red blood cell side.

3. How to Use It as a Micro-Blood Sampler

A glass capillary tube is used, and the blood is collected and the sealed capillary tube is centrifuged as in normal use. The glass capillaries are used because they are folded in the process of centrifugation. After centrifugation, a scratch is made on the border between the blood cell column and the plasma, slightly closer to the plasma, with a glass cutter, and the capillary is folded.

The broken capillary is placed in a collection vessel (e.g., microtubes) and centrifuged to collect the plasma in the vessel. Since this method is difficult to perform, recently, a special device for micro-sampling has been developed.