[Q&A] June 9, 2017

The first type of hazard originates from the interactions between charged bodies. When the aircraft fuselage comes into contact with air, water vapor, dust, and other particles, it becomes charged electrically. Without any preventive measures, this can severely disrupt the normal operation of the aircraft’s radio equipment, rendering the aircraft “deaf and blind” ； In printing plants, static electricity between paper sheets can cause them to stick together, making it difficult to separate them and causing problems during printing ； In a pharmaceutical factory. Due to electrostatic attraction, dust accumulates, preventing the drugs from achieving the required purity level ； When a TV is on, static electricity on the screen surface tends to attract dust and oil, forming a thin layer of dirt that reduces both the clarity and brightness of the image ； The dust that is common on blended clothes and difficult to remove is also caused by static electricity. The second major hazard of static electricity is the possibility of explosions occurring when static sparks ignite certain flammable materials. On dark nights, when people take off nylon or woolen clothing, sparks and popping sounds are produced; this is basically harmless to the human body. But on the operating table, electric sparks can cause an explosion of the **agent, harming both doctors and patients ； In coal mines, it can cause gas explosions, resulting in casualties among workers and the abandonment of the mine. In summary, electrostatic hazards originate from electric power and static sparks; among these hazards, the most severe is electrostatic discharge, which can cause flammable materials to ignite and explode. It is often said that prevention is better than cure. Measures to prevent static electricity generation generally involve reducing flow velocity and volume, modifying processes prone to charge generation, and using equipment and materials that generate less static electricity. The simplest and most reliable method is to ground the equipment with wires, which allows charges to be directed into the ground and prevents static electricity from building up. Attentive passengers will probably notice that ； Discharge brushes are installed at both wingtips and the tail of the aircraft. When the plane lands, to prevent passengers from getting electrocuted upon disembarking, special grounding tires or grounding wires are typically used on the landing gear ； To discharge the static electricity generated by the aircraft in the air. We also often see an iron chain trailing from the rear of oil tankers; this is the vehicle’s ground wire. Appropriately increasing the humidity in the working environment allows charges to dissipate at all times, which can also effectively eliminate static electricity. This is why it’s difficult to conduct static electricity tests in humid weather. The antistatic agents studied by researchers can effectively eliminate static electricity within insulators. However, everything has two sides. Regarding static electricity, this hidden troublemaker. As long as one understands its temperament and makes use of its strengths while avoiding its weaknesses, it can also be used to serve humanity. For example, technologies such as electrostatic printing, electrostatic spraying, electrostatic flocking, electrostatic dust removal, and electrostatic sorting have been widely applied in industrial production and daily life. Electrostatics is also playing an important role in various applications such as desalinating seawater, applying pesticides, inducing artificial rainfall, and cryogenic freezing; even spacecraft are equipped with electrostatic devices such as electrostatic feeders.

The first type of hazard caused by static electricity stems from the interactions between charged bodies. The second major hazard of static electricity is the possibility of explosions occurring when static sparks ignite certain flammable materials.

There are three hazards associated with static electricity: first, it can cause explosions and fires. Although the energy of static electricity is not large, its high voltage and tendency to discharge result in the appearance of static sparks ； Second, it may cause electric shock. Although electric shocks caused by static electricity are not fatal, they often lead to secondary accidents, so precautions are also necessary ； Third, it may affect production. In production, static electricity may affect the normal operation of instruments and equipment or reduce the quality of products. In addition, static electricity can also cause malfunctions in electronic automatic components.

In principle, a reciprocating pump is a type of positive displacement pump. It relies on a piston or plunger that moves back and forth within the pump cylinder to change the volume of the working chamber, thereby enabling the suction and discharge of liquids. As long as the plunger force and the strength of the working chamber are sufficient, in theory the pump pressure can be infinitely high (ignoring leaks). In reality, the plunger force (provided by the power machine) and the strength of the working chamber (determined by the materials and structure) are always limited. Therefore, if the pressure continues to rise, the result is either the destruction of the power machine or damage to the working chamber. Therefore, before starting the pump, all the discharge valves in the piping system must be opened; it is not allowed for the discharge lines to become blocked, as this could lead to equipment damage or injuries. To ensure safety, a safety valve must also be installed on the pump’s discharge line, so that the discharge pressure does not exceed its rated value. This means that, during startup and operation, reciprocating pumps operate in the opposite way to centrifugal pumps – before starting a centrifugal pump, the discharge valves in the piping system must be closed, thereby minimizing the starting power required. This is what we usually refer to as open-starting for reciprocating pumps and closed-starting for centrifugal pumps.

Static electricity can cause fires and explosions; in daily life, it causes problems and leads to physical discomfort

①Production failure； ②Fires and explosions ； ③Secondary disasters caused by static electricity shocks in the human body.

1. Can cause explosions and fires； 2. Can cause personal injury ； 3. Static electricity can hinder production.

Prolonged exposure of the human body to static electric radiation can cause irritability, headaches, chest tightness, difficulty breathing, and coughing. In family life, static electricity can occur not only in synthetic clothing, but also on carpets under our feet, in everyday plastic items, painted furniture, and even various household appliances. Static electricity can attract a large amount of dust from the air; the greater the charge, the more dust it can attract. Dust often contains various toxic substances and pathogens, which can cause skin irritation, affecting its brightness and smoothness. In severe cases, it can lead to rashes and sores on the skin, and in even more serious situations, it may trigger conditions such as bronchial asthma and arrhythmia. Static electricity is mainly caused by clothing; friction from synthetic fabrics can generate electricity. During the dry season, when this gradually building up static voltage exceeds 3000 volts, a \"stinging\" effect occurs; a humming sound can be heard during discharge, and touching the conductor causes a tingling sensation. Although the static electricity on the human body has a high voltage, the current is very low, so it does not pose a risk similar to that of an electric shock

When the human body is exposed to static electricity over a long period of time, it can cause irritability, headaches, chest tightness, difficulty breathing, and coughing. In daily life, static electricity can occur not only in synthetic clothing but also on carpets, plastic items used in everyday life, shiny painted furniture, and various household appliances. Static electricity can attract a large amount of dust from the air; the greater the charge, the more dust it can attract. Dust often contains various toxic substances and germs, which can, in mild cases, irritate the skin and affect its texture and smoothness, while in more severe cases, it can cause rashes and sores on the skin. Even more serious consequences can include conditions such as bronchial asthma and arrhythmia.