Spherical Roller Bearings have two rows of rollers, a common sphered outer ring raceway and two inner ring raceways inclined at an angle to the bearing axis . The centre point of the sphere in the outer ring raceway is at the bearing axis. Therefore, these bearings are self-aligning and insensitive to misalignment of the shaft relative to the housing, which can be caused, for example, by shaft deflection. Spherical Roller Bearings are designed to accommodate heavy radial loads, as well as heavy axial loads in both directions. Spherical Roller Bearings Spherical Roller Bearings,Spherical Ball Roller Bearing,Steel Spherical Roller Bearing,Asymmetrical Spherical Roller Bearings Ningbo Ritbearing Imp & Exp Co.,Ltd. , http://www.ritbearingchina.com
The quality of drinking water is a health issue because water is the medium of disease transmission. In Southeast Asia, as in other developed regions, there may be significant water quality problems. Among these problems, contamination of drinking water sources by pathogenic microorganisms remains the most important issue.
The main factors influencing the global water treatment market come from environmental regulatory agencies. More and more countries are adopting strict policies and regulations to promote the adoption of environmentally friendly products, especially products involving human contact.
As a result, in order to meet the rapidly changing environmental requirements of the world, the demand for water treatment products is on the rise. The needs of economies from Asia and Latin America, especially China, India and Brazil, are driving the growth of the entire water treatment equipment and services market.
The demand for cleaner, purer water creates a powerful fact that the rapid development of mobile water treatment devices in the Asia-Pacific region. The mobile system can provide a range of processing options including: clarification, filtration, desalination, reverse osmosis, membrane separation, and induced air/gas flotation. The system is a skid-mounted structure that can be installed on site or on a trailer. The trailer contains instruments and equipment and is fully automated.
In addition, the scale of water treatment plants is also varied, and no two plants are exactly the same. However, whether they are state-owned, private, or mobile water treatment plants, they all have the same goal - to provide a safe and reliable source of drinking water for the customer community. Liquid analysis systems play a vital role in maintaining water plant safety.
To deal with contaminants in raw water sources used, water companies should select the appropriate combination of water treatment processes. Common processes include: pretreatment, agglomeration, flocculation, sedimentation, filtration, and disinfection. Other treatments include ion exchange, reverse osmosis, and Adsorption.
In each of these processes, optimizing the use of liquid analysis measurements will save water treatment plants time and money, and help increase water purity and safety. In addition, optimizing the use of these measurements also helps improve process and related by-products.
Pretreatment In order to better define the dynamic characteristics of raw water sources used in water treatment plants, some liquid analysis measurements are performed before entering the treatment process. Influent monitoring measurements include: pH, conductivity, temperature, turbidity, and dissolved oxygen.
Some water plants also need to keep a permanent record of each measurement for future reference, or to detect seasonal changes in source water sources.
Before the water is clarified, large filters need to be removed through the coarse filter to prevent them from entering the water treatment plant. Pretreatment also includes a one-time disinfection process that uses chlorine or ozone to treat the growth of algae and the oxidation of chemicals and microorganisms.
Caustic soda is one of the basic chemical building blocks. Because of this, it has a variety of applications, one of which is water treatment. Municipal water treatment facilities use caustic soda to adjust pH, ion exchange regeneration, and sodium hypochlorite production. Especially when controlling pH, caustic soda neutralizes waste acids, there are other similar applications. Caustic soda can be used against other bases, especially sodium carbonate (soda ash). A common factor in the selection of caustic soda is its more basic nature, ease of storage and handling.
The pretreatment is the first step in the water treatment. In the front of the filter bed of the mixing tank, the annular electrical conductivity can be used to measure whether the fluid contains caustic soda. The measurement result can indicate whether the feed pump works normally. The ring-shaped conductivity sensor is durable in this application, and a drop in the conductivity value indicates that the feed pump has not injected caustic soda into the aqueous fluid.
Primary disinfection Since water is a universal solvent, it comes in contact with a variety of different pathogens (bacteria, viruses and parasite protozoa), some of which are well known and may be fatal. Both surface and groundwater sources may be contaminated with these pathogens, and chemically disinfected and mechanically filtered processes can be used to inactivate pathogens.
Chlorine can be used as a chemical disinfectant for drinking water, and ozone (O3) is also a strong disinfectant used in water treatment. Compared with chlorine disinfection, ozone disinfection attacks the pathogens in water faster than the chlorine disinfection, thereby reducing the concentration of organic substances, iron, manganese, and sulfur, and reducing or eliminating the problems of smell and taste.
Chlorine, as a slow oxidant, has limited effects on bacteria, and Cryptosporidium and Giardia are very resistant to chlorine. Ozone treatment as a rapid and effective treatment technology is becoming more and more popular in a disinfection process.
The ozone air bubbles upwards by contacting the water in the container. When the water reaches the end of the container, one disinfection is completed and the ozone is converted back to oxygen. For proper ozone disinfection, proper water contact time and proper ozone input are required.
Clarification After pretreatment and primary disinfection, raw water clarification is usually a multi-step process with the aim of reducing water turbidity and suspended solids. Clarification usually includes coagulation, flocculation, and precipitation processes.
The smaller particles bind or "coagulate" into larger fluffy particles, called "flocs," which precipitate the sediment in the raw water source. The coagulation process is promoted by adding chemical coagulants such as alum, iron salts or synthetic organic polymers. After the chemicals were added, water flowed through the mixing channels and flash mixed in the mixing channels.
The flocs are mechanically stirred in order to adsorb suspended solids and microorganisms. It is important to maintain the proper pH during this process as it will improve the coagulation process and reduce the turbidity of the water.
If raw water sources have unusually high hardness, chemicals such as lime and soda ash need to be added to the water to reduce the calcium and magnesium content. The lime softening method can make the hardness of the water reach 60-120 ppm. However, this method causes the pH of the water to be high. Therefore, the treated water needs to be buffered to lower the pH so that it can reach an acceptable value for subsequent processes.
The flocs settle to the bottom and sludge forms in the sedimentation tank. As dirt and chemicals get heavy enough, they sink to the bottom of the pool, allowing larger particles to settle or settle out naturally. The sludge is removed by a mechanical scraper and disposed of properly. Water is removed from the surface of the sedimentation basin and flows into the sinking water channel.
The filtration and sedimentation process removes particles larger than 25 microns, but the process is not 100% efficient and therefore requires further filtration. The water turbidity entering the filtration process is 1-10 NTU.
The water flows through a sand filter and percolates down through a combination of sand, gravel, anthracite, and a mixture of gravel and fine sand. Larger particles are first blocked, smaller particles such as clay, iron, manganese, Microorganisms, organic matter, sediments and sludge from other processes will also be removed, resulting in clear water.
The filtration process also removes the residual substances produced by the oxidation reaction of organic chemicals and microorganisms during the primary disinfection process, and removes chlorine- and/or ozone-resistant microorganisms during the pretreatment process.
The filter must be backwashed periodically to remove the build-up of deposits on the filter media. Continuous monitoring of the effluent of the filter bed with a turbidimeter can be used as an indicator of filter performance and filter backwash requirements. The turbidity parameter reflects the clarity of the sample, and appearance of turbid water is caused by tiny particles in the water. Turbidity measurements also help monitor and increase the efficiency of the plant. High turbidity values ​​indicate that the filter is not working properly and backwash is required.
Government rules and regulations apply to public water systems, which require water treatment plants to minimize harmful microorganisms and viruses. It is envisaged that the filtration system can accomplish the process of reducing the harmful Cryptosporidium, Giardia, and viruses to the lowest percentage by satisfying a specific turbidity limit, combined with adequate disinfection.
By measuring the turbidity of the effluent of the combined filter, the adequacy of the filtration process and the removal of microorganisms can be determined to meet the government's standards. This standard includes: frequency of turbidity monitoring, maximum turbidity limit, and approved turbidity measurement method.
Secondary disinfection Secondary disinfection is to prevent the re-growth of certain pathogens, which are contaminated by backflow into or introduced into the treatment plant. In order to comply with the secondary remaining disinfection regulations, the factory must perform secondary disinfection with chlorination at the final processing step. Today, chlorination uses chlorine (CI2), sodium hypochlorite (NaOCl) or chlorine dioxide (CIO2) as secondary disinfectants.
When chlorine is added to the water, the free chlorine forms a mixture of hypochlorous acid (HOCI) and hypochlorite ion (OCI-), the relative amount of each substance depends on the pH value, hypochlorous acid (HOCI) and hypochlorite ion ( The total amount of OCI-) is defined as free chlorine (free chlorine). For disinfected water, hypochlorous acid (HOCI) is not only more active than hypochlorite ion (OCI-), but also has stronger disinfection and oxidation. Hypochlorous acid (HOCI) is hypochlorite ion. (OCI-) 80-100 times.
Chlorine chloride by-products were found in drinking water in 1974. When chlorine reacts with bromine and the presence of natural organic matter in the water source, chlorinated by-products are formed, which have potential health effects on humans. In analytical instruments, chlorine diffuses inside the sensor through a semipermeable membrane, and the sensor produces a current signal proportional to the chlorine concentration.
There are currently chlorine disinfection methods, such as chloramines. This method of disinfection requires the addition of chlorine and ammonia compounds to the water, with proper control to form chloramines.
Chloramine produces fewer chlorinated by-products than chlorination, and these by-products exist in the form of monochloramine, dichloramine, and trichloramine. Monochloramine is the most desirable of the three forms because It has little or no taste or odor and is considered to be the most effective disinfectant. Plant operators using chloramines for disinfection need to accurately determine the amount of monochloramine used in the water treatment system.
The final treatment of many water systems already has ammonia in the water, or addition of ammonia during the process. The excess ammonia in the water distribution system will promote biological growth and nitrogen nitrification. If the system is located in a remote area where water quality is degraded, poor water quality can affect the sensory quality of water (such as water taste, smell, and particulates). If the system is located in areas where it is difficult to consistently provide acceptable chlorine, it may directly lead to biological growth and nitrification of nitrogen.
The term “free ammonia†is used when the water naturally contains ammonia or when it is sterilized with chloramine. In the chlorination process, chlorine and ammonia are added to the water to form monochloramines. Some of the ammonia that is not chlorinated is called free ammonia. According to the pH and temperature of the water, free ammonia exists as NH4+ or NH3.
The typical pH of the water is 7.0-7.8, the temperature is 12-24oC, and more than 96% of the ammonia is in the form of ammonium ions (NH4+). As the pH and temperature increase, the content of NH3 increases and the content of NH4+ decreases.
The only accurate way to determine if the treated water contains ammonia is to perform ammonia analysis. If ammonia is detected, additional sampling devices need to be explored in the free ammonia delivery system. The ammonia content of groundwater is 0.2-2.0 mg/L.
Municipal drinking water plants carefully control the content of free ammonia (usually also described as total nitrogen or NH3-N) and chloramine (also commonly known as monochloramine or MCL),
To ensure that water is suitable for human consumption. Can provide single measurement system operation panel or dual measurement system operation panel.
One of the most significant new trends in water treatment for water treatment wireless solutions is the use of wireless analysis technology in remote or hard-to-reach locations. Wireless monitoring of pH and conductivity plays a key role in many areas of the municipal water market. New wireless pH and conductivity transmitters can be integrated into the water plant's network, making wireless technology a breeze.
New adapter technology enables wireless technology to be added to analytical instruments with HART communication capabilities without software upgrades, batteries, or additional hardware, making it cost-effective, scalable, and simple to convert wired systems to wireless systems Easy to use, this method can save 90% of installation costs for water plants.
In addition, the wireless analyzer can pass process variables and diagnostic data to the central control system, reducing on-site personnel and maintenance workload.
The new system is equipped with on-board data logging capabilities that allow process data and events to be transferred to USB storage devices for computer analysis, making water plant control systems more flexible.
In the water industry, the first obvious benefit of wireless technology is that it requires no power and no wiring to communicate with the host. Water plants and networks can integrate wireless pH and conductivity analyzers and sensors easily and cost-effectively, regardless of difficult wiring challenges or remote installation locations.
Bearing performance is not only determined by load or speed ratings. There are a number of other factors that contribute to bearing performance. To a large extent, performance is influenced by the geometry of the rollers, raceways and cages, the heat treatment during manufacture, as well as the surface finish of all contact surfaces.
Purity analysis of drinking water
RyoHashimoto detailed the use of analytical measurements and the important role that analytical measurements play in ensuring the quality and safety of drinking water. Ample, quality-safe water is essential for human survival. From a regional perspective, Asia is facing severe water supply pressures, mainly because of the high population density in Asia and the large amount of water used by agriculture and industry.