月: 2023年2月

What Is a Pipe Joint?

A pipe joint is a component used to connect pipes together. Also known as a joint or connector, pipe joints include various types such as ferrules and couplers. This text focuses on the most commonly used threaded pipe joints. Pipe joints differ in shape based on the connection’s direction, number, and diameter, with the material choice depending on the pipes being connected.

Typically, joints are made from the same material as the pipes, though there are joints designed for connecting different materials, such as PVC to cast iron. Selection of pipes and joints must consider the fluid type, environmental conditions, and desired service life.

Uses of Pipe Joints

Pipe joints facilitate the connection of pipes. Threaded pipe joints vary depending on the connection’s direction, number, and diameter.

Examples include elbows (street elbows) for 90° bends, sockets (nipples) and couplings for straight connections, bushings for different diameter connections, caps (plugs) for closing pipe ends, and tees for three-way branching.

These products are further categorized by whether they connect to internally or externally threaded pipes and are sold by diameter, requiring careful selection to ensure compatibility.

Features of Pipe Joints

Threaded pipe joints feature either external or internal threads, matching the threading of the pipes they connect. Sealing tape is typically wrapped around the threads to seal and secure the connection.

Pros

Connecting pipe joints does not require welding or gluing, simplifying repairs and maintenance.

Cons

Connecting threaded pipes can be time-consuming. Additionally, using a pipe wrench may damage the plating, often necessitating repair of the affected area.

Types of Pipe Joints

Pipe joints are classified by their connection type and application.

1. For Linear Connection

Sockets or unions are used for straight connections between two external threads, while nipples are used for internal threads. Bushings connect threads of different diameters, primarily to extend pipes.

2. Bending and Connecting

Elbows are used for 90° bends, and 45° elbows for 45° bends. Street elbows connect an external thread to an internal thread at a 90° angle.

Use elbows or street elbows instead of bending pipes directly.

3. When Connecting in Multiple Directions

Tees are used for T-shaped 3-way branching, and crosses for 4-way branching.

4. When Used at the End

Caps close the end of an external thread and plugs close the internal threads.

How to Select Pipe Joints

Choose pipe joints made of the same material as the pipes. Each material suits specific applications and purposes. Key materials include:

1. Galvanized Joints

Hot-dip galvanized surfaces offer rust and corrosion resistance, suitable for various fluids and gases, including industrial and cooling water, fire water, and oil.

2. Black Fittings

Made from black core malleable cast iron without plating, these fittings are suitable for a wide range of fluids, including water, oil, steam, gas, and air, noting slight differences from galvanized fittings.

3. Epoxy Resin Coated

Resin-coated joints are used for water and other fluids up to 40℃, excluding high-temperature applications.

4. PVC Pipe Joints

Made from rigid polyvinyl chloride, PVC joints vary in heat resistance: 60°C for VP pipes and 90°C for HT pipes.

What Is Wood Tar?

Wood tar, a byproduct of dry distilling wood, is a sticky black liquid used for its strong odor to repel vermin and protect crops. It separates from wood vinegar during cooling and settling, yielding two distinct layers: a lighter wood tar and a heavier, sediment layer.

Uses of Wood Tar

Employed mainly as a natural repellent, wood tar’s distinct smoky aroma deters wildlife and pests, simulating the presence of fire. It’s also utilized for its disinfectant properties in medicinal products derived from wood creosote.

Characteristics of Wood Tar

Advantages

• Effective against a wide range of pests without harming people or soil.
• Natural material with disinfectant effects.

Disadvantages

• Strong smell restricts indoor use and direct skin contact may irritate.
• Contact with plants can inhibit growth.

Types of Wood Tar

Wood tar is classified into light (soluble) and heavy (submerged) types, based on its density and solubility in wood vinegar. Market-available repellents vary in form, including liquid, granular, and solid, tailored for different applications.

How to Select Wood Tar

Choose based on the repellent’s form, considering factors like the target pest, application environment, and seasonal conditions. Liquid types offer resilience to rain, while solid types may require protection from weather elements.

How to Use Wood Tar

• Liquid Type: Apply in intervals along the field’s perimeter or areas prone to pest infestation.
• Solid Type: Position above ground level to avoid wash-off by rain, encircling protected zones.
• Granular Type: Spread generously, adjusting the application based on plant sensitivity and pest control needs.

When using wood tar products, it’s crucial to consider the specific instructions for each type to maximize effectiveness while minimizing unintended effects on plant growth.

What Is a Hot Water Heater?

In a greenhouse, a hot water heater is a system that heats the space by circulating hot water through pipes installed within the greenhouse. This water is heated by a boiler or similar device, and the rising warm air from the hot water creates a stable, uniform heating environment.

Uses of Hot Water Heaters

Hot water heaters are commonly used in greenhouses for high-value crops like orchids and greenhouse melons, where precise temperature and humidity control are crucial. However, they are less suitable for crops like strawberries and tomatoes that do not benefit as much from this type of heating.

Due to their high equipment costs, hot water heaters are typically used in larger facilities or for crops that command higher market prices.

Characteristics of Hot Water Heaters

Advantages

1. Temperature and Humidity Control: Hot water heaters can maintain moderate humidity levels and gradual temperature changes, ensuring uniform growth of crops.

2. Reduced Air Current Impact: The gentle airflow produced by hot water heaters minimizes the impact on sensitive crops.

3. Residual Heat: These heaters retain a significant amount of heat, providing temperature stability even in the case of equipment failure.

Disadvantages

The primary disadvantage is the high initial cost, making it an investment that needs careful consideration based on the expected return and the size of the facility.

Types of Hot Water Heaters

Hot water heaters can be categorized based on their fuel source:

1. Fossil Fuel-Based Heaters:

These heaters use fossil fuels like oil and are known for their high energy efficiency and ease of storage and transportation. However, the rising costs of fossil fuels and environmental concerns are shifting the preference towards biomass-fueled heaters.

2. Biomass-Fueled Heaters:

Biomass heaters, using renewable resources like wood chips, help reduce carbon dioxide emissions and can be a cost-effective alternative.

How to Select a Hot Water Heater

When selecting a hot water heater, consider the optimum temperatures for both crop growth and insect activity, especially when insects are used for pollination or as natural predators. It’s also important to weigh the initial investment against the potential returns from the crops being cultivated.

What Is a Bug Zapper?

A bug zapper typically refers to an electric device that attracts and eliminates insects. These devices use ultraviolet light to lure insects, which are then killed by an electric shock. The device mainly consists of a UV light source to attract insects and an electrified grid that delivers the fatal shock. Insects are drawn to the UV light due to their phototactic behavior, which describes their movement towards light sources.

Uses of Bug Zappers

Bug zappers are used to reduce the presence of insects in various environments, improving working and living conditions. Electric bug zappers offer the advantage of being chemical-free and effective over a wide area. They come in various forms, including stationary, hanging, and hand-held racket types. Their suitability for indoor or outdoor use varies based on their design, particularly in terms of water and weather resistance.

However, these devices are most effective against insects attracted to light and may be less effective against pests like cockroaches, flies, and mosquitoes, which are not as drawn to UV light.

What Is a Jet Pump?

A jet pump is a device that employs a fluid or steam jet to create negative pressure for suctioning material. Similar to an aspirator or ejector, it mixes the operating fluid with the target fluid to achieve high pressure, making it particularly effective for applications requiring high pressure but lower flow rates.

Applications of Jet Pumps

Jet pumps are versatile, and used in applications ranging from recirculation systems in nuclear reactors to well water extraction due to their compact design and ability to achieve the high pressures necessary for deep wells.

Features of Jet Pumps

Advantages

• Compact size with superior suction power compared to centrifugal pumps.
• Capable of suctioning water from depths up to 20 meters, ideal for well applications.
• Enhances crop quality and yield through three-dimensional growth support.

Disadvantages

• Operational noise and high energy consumption.
• Less suitable for use during disasters due to reliance on electricity.

Types of Jet Pumps

Differentiated by their suction heights and applications, jet pumps cater to both shallow and deep well needs, with variations such as injectors for high discharge pressure and ejectors for handling both gases and liquids.

How to Select Jet Pumps

• Suction Height: Choose based on the water source’s depth.
• Noise Level: Opt for quieter models if noise is a concern.
• Power Output: Select according to water usage, with 250W-400W models common for home use.

How to Use Jet Pumps

Jet pumps work in tandem with shallow or deep well pumps, typically servicing depths of 8 to 20 meters. Regular maintenance of the jet section and timely replacement of parts like the accumulator and switch ensure longevity and efficiency.

What Is a Binding Tape?

Binding tape is a versatile product designed to secure items together, notably used in agriculture for bundling fruits and vegetables, as well as in various industries to organize cords and cables.

Uses of Binding Tapes

Primarily, binding tapes bundle agricultural produce for sale or transport. They also serve in managing cords and cables, aiding in organization and identification.

Characteristics of Binding Tapes

Advantages

• Facilitates easy bundling of items without the need for metal fasteners.
• Generally easy to cut and remove without leaving adhesive residues.

Disadvantages

• Potential for slipping or breaking under excessive weight or number of items.
• Requires careful application to ensure secure bundling.

Types of Binding Tapes

• Vegetable Binding Tape: Suitable for bundling produce, often adhesive-residue-free and compliant with food safety regulations.
• Cord and Cable Binding Tape: Flame retardant options for home appliances, available in multiple colors for easy identification.
• Electrical Wire Binding Tape: Non-conductive tapes ensuring safe cable management, also available in various colors.

How to Select Binding Tapes

Selection should be based on the specific application:

• Choose food-safe, residue-free tapes for fruits and vegetables.
• Opt for flame-retardant tapes for home appliances and electronics.
• Select electrically insulating tapes for electrical wires.
• For construction materials, prefer tapes that bond securely without leaving residues.

How to Use Binding Tapes

Ensure tape is applied tightly and without gaps to prevent items from slipping. Utilizing specialized binding equipment can enhance efficiency and stability, particularly for agricultural products.

What Is a Hose Coupling?

A hose coupling is a connector used to attach a hose to a faucet, crafted from materials like plastic or metal for durability and resistance to pressure and weather. Available in various sizes and designs, these couplings make it easy to connect and disconnect hoses, enhancing convenience for tasks like watering or cleaning.

Usage of Hose Couplings

Commonly employed in outdoor watering, equipment cleaning, and hydroponics, hose couplings ensure a secure connection to prevent disconnection under pressure. They allow for extended hose lengths, offering flexibility in water supply across distances.

Features of Hose Couplings

Advantages

• Facilitates direct water supply from faucet to hose end, covering large areas easily.
• Prevents hose detachment with a specially designed connection surface.
• Enhances hose longevity by minimizing direct attachment/detachment.

Disadvantages

• Variety in diameters necessitates careful selection to match faucet and hose sizes.

Types of Hose Couplings

• By Bore Diameter: Common sizes include 25mm and 50mm, with step-type couplings accommodating various hose sizes.
• By Type: Options include direct-insert and one-touch couplers for frequent connections.
• By Material: Choices between plastic and metal affect pressure and weather resistance.
• By Use: Distinctions between faucet connectors and hose-to-hose connectors.

How to Select Hose Couplings

Selection criteria should focus on matching the bore diameter with your hose and faucet and choosing materials based on environmental conditions and water pressure levels. Step-type couplings are recommended for versatility across multiple hose sizes.

How to Use Hose Couplings

Attach the coupling to the faucet before connecting the hose to ensure a smooth and secure setup. This straightforward process allows for efficient water supply management for various applications.

What Is Mulch?

Mulch is a layer applied to the soil surface, available in natural or synthetic forms, to regulate soil temperature and moisture, suppress weeds, and enhance aesthetic appeal.

Uses of Mulch

Mulch serves multiple purposes, from protecting roadside trees and flower beds to insulating home plants and agricultural products. It’s instrumental in agriculture for packaging delicate fruits, seedling cultivation, and as a gardening aid for flowerpots.

Characteristics of Mulch

Advantages

• Maintains optimal soil humidity and temperature.
• Prevents weed growth and soil erosion.
• Offers frost and disease protection.
• Enhances the visual appeal of planters and landscapes.

Disadvantages

• Can be costly for extensive use and disposal.
• Makes it challenging to monitor soil conditions directly.
• Potential for unnoticed mold and insect infestations.

Types of Mulch

Mulch materials range from natural options like wood chips, bark, and coconut fiber, to synthetic varieties like polyethylene sheets, each with distinct benefits and applications:

Natural Mulch

• Wood and bark chips for insect repellence and soil protection.
• Coconut fiber and humus for style and soil improvement.
• Bamboo mulch for pest suppression and yield enhancement.
• Stone mulch for stylish decoration and root protection.

Artificial Mulch

• Black mulch sheets for soil warming and weed prevention.
• Transparent mulch sheets for light transmission and moisture retention.
• Silver mulch sheets for deterring pests with reflective properties.

How to Select Mulch

Selection should be based on specific needs, including the plant types, intended purpose, and the growing environment. Consider the mulch’s impact on indoor and outdoor applications and select materials that align with your aesthetic and functional requirements.

What Is a Foam Sheet?

Foam sheets are versatile, lightweight materials known for their cushioning and insulation properties. Made from various resins like polyethylene, polypropylene, and vinyl chloride, they feature a bubble structure that contributes to their impact resistance and thermal insulation capabilities. These sheets are adaptable across numerous industries, including agriculture, construction, transportation, and automobile manufacturing, owing to their excellent processability.

Uses for Foam Sheets

Foam sheets serve a broad range of applications:

• Roads: Marking stakes and land boundaries.
• Agriculture: Packaging for delicate produce and seedling cultivation.
• Construction: Insulation for pipes, moisture-proof underlayments, and buffer materials.

Features of Foam Sheets

Advantages

• Lightweight and easy to manipulate for various applications.
• Resistant to weather, water, and moisture, enhancing durability in diverse environments.
• Cost-effective due to low manufacturing and processing costs.
• Available in multiple colors, suitable for specific visibility requirements or aesthetic preferences.

Disadvantages

• Reduced durability and strength with thinner sheets, limiting support for heavy items.
• Combustibility, requiring caution near open flames.

Types of Foam Sheets

Foam sheets are categorized based on the resin materials used, each offering distinct properties:

• Foam Polyethylene Sheet: Versatile, available in different foam ratios and structures for a wide range of uses.
• Foam Polypropylene Sheet: Lightweight, rigid, chemical resistant, suitable for tatami mats, curing sheets, and packaging.
• Foam PVC Sheet: Durable, shock-absorbing, buoyant, and flame-retardant, ideal for protective cushioning and insulation.

Eco-friendly options made from plant-derived materials are also available, catering to environmentally conscious applications.

How to Dispose of Foam Sheets

Disposal practices vary by local regulations. While households typically treat foam sheets as plastic waste, businesses may need to follow specific disposal procedures for commercial waste.

What Is a pH Indicator?

A pH indicator is a generic term for organic dyes that change color with changes in pH. They are also called acid-base indicators or neutralizing indicators. The pH at which the reaction that changes the structure of the indicator occurs differs depending on the indicator. Therefore, it is important to select an indicator that matches the pH range to be checked. Phenolphthalein, which changes colors in basic solutions, is a typical pH indicator.

Most pH indicators are often used in R&D and production in the manufacturing industry and are also used to check the pH of crops and soil. In addition, pH indicators have long been used in school education, such as science classes, because of their large color change and ease of use.

Uses of pH Indicators

Since pH indicators can easily determine the pH of a sample solution, they are widely used, especially in analytical applications. For example, in the manufacturing industry, they are often used at production sites to check the neutralization point or to check the pH of wastewater. In particular, the pH range of wastewater discharged from factories to the sewage system is set by the government, so pH control of the wastewater is essential.

In addition, it is sometimes used to check the pH of soil and food in agriculture. In particular, pH measurement is extremely important for stable crop growth because soil pH has a significant impact on how crops grow, and the optimal pH varies depending on the crop and the original pH of the soil in different regions.

Principle of pH Indicators

The color of the pH indicators changes because the chemical structure of the pH indicators changes with changes in pH. The change in the aromatic ring and the position of the double bond changes the energy state of the molecule (HOMO and LUMO energies), resulting in a change in the wavelength of the light absorbed.

1. BTB Solution

Figure 1. Structural changes in BTB

BTB solution (bromothymol blue) is used for pH indicators to distinguish between acid and base because the color of BTB varies greatly among acidic, neutral, and basic solutions. Strictly speaking, BTB is acidic, so the chemical structure of commercial products is sodium salt.

When the pH of a BTB solution is less than 6.0, almost all BTB forms a salt with sodium, but when the pH is greater than 7.6, the proton of the hydroxy group of BTB is also desorbed to form a divalent anion. This structural change results in a color change: yellow for pH less than 6.0, blue for pH greater than 7.6, and green for pH in between, which is a superposition of the colors of the two compounds.

2. Phenolphthalein

Figure 2. Structural changes in phenolphthalein

Phenolphthalein solution in pH indicators is used to identify basic solutions. It is often used in school science experiments because of its easily recognizable purple coloration.

Phenolphthalein is a white solid substance that is soluble in ethanol and water. Phenolphthalein solutions in neutral or acidic environments are clear, but when the pH exceeds 9, the ether moiety cleaves and changes to an anion, turning the solution purple. On the other hand, above pH 10, phenolphthalein undergoes further structural changes, and above pH 13, the purple solution returns to clear and colorless.

Other Information on pH Indicators

1. pH Indicators in the Manufacturing Industry

Figure 3. pH indicator use in the manufacturing industry

The pH of wastewater that can be discharged into the sewage system by businesses is set by each municipality and must be neutral. In cases where the amount of wastewater used is small, such as in laboratories and R&D, a weak base such as sodium bicarbonate is used as a neutralizing agent, and pH indicators, which change color near neutral, are added to the wastewater to check its pH.

However, neutralization using sodium bicarbonate generates carbon dioxide gas, which in some cases cannot be used at production sites on large scales. In such cases, neutralization may be performed using a base or acid such as hydrochloric acid or sodium hydroxide that does not generate gas.

Since the indicator cannot be added directly to the wastewater at the production site, the wastewater is sampled after treatment and the indicator is added to check the pH level.

2. Use of pH Indicators in Agriculture

In agriculture, soil pH is controlled due to its significant impact on crops. In addition, pH confirmation is often required not only for crops but also for a wide range of food products.

For example, for foods that dissolve in water, such as dried soup, pH indicators may be added to the food dissolved in water for simple analysis. For solid foods such as meat and fish, a pH measuring instrument using an electrode is used instead of pH indicators.