A sleeping bag (sleeping bag) is a bag used for sleeping. The vast majority of sleeping bags on the market are labelled with a comfort temperature and an extreme temperature. The comfort temperature is the range of temperatures at which the user sleeps throughout the night, with a maximum and a minimum. The maximum comfort temperature is the kind of heat you feel in a sleeping bag but not when you are sweating profusely, and is generally defined as a sleeping bag with the zip open, arms outside and the head of the bag not tightened, etc.
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First, the common sight of leakage
　　
The proportion of mechanical seal leakage accounted for more than 50% of the full maintenance of the pump, mechanical seal black and white directly affect the normal operation of the pump, are summarized as follows.
　　
Periodic leakage
　　
(1) The axial displacement of the pump rotor is large, and the interference between the seal and the shaft is large. The moving ring can not move sensitively on the shaft. In the pump flip, moving, static ring wear, no compensation for displacement.
　　
Countermeasures: In the assembly of mechanical seals, the shaft axial movement should be less than 0.1mm, auxiliary seal and shaft interference should be moderate, the radial seal in the package also, moving ring pump equipped with the package can be on the shaft Sensitive movement (the ring pressing the spring can be free to bounce back).
　　
(2) the lack of smooth surface sealing oil caused by dry friction or hair sealing surface.
　　
Countermeasures: Oil chamber cavity smooth surface height should be added to the dynamic and static seal surface.
　　
(3) Rotor periodic vibration. The reason is that the stator is not aligned with the upper and lower end caps or the impeller and spindle are unbalanced, cavities or bearings are damaged (worn out), which can shorten the sealing life and cause leakage.
　　
Countermeasures: can be based on maintenance norms to correct the above problems.
　　
2. Small submersible sewage pump seal leakage caused by grinding axis scene
　　
(1) 715kW the following small pump seal off effect often occurs grinding shaft, grinding shaft position mainly in the following: moving ring auxiliary seal ring, static ring position, a small amount of spring grinding shaft scene. Drum pump
　　
(2) The main reason for the grinding shaft: â‘ BIA double mechanical seal, the back pressure form is a bad task, the medium of particles, impurities can easily enter the sealing surface, the seal out. â‘¡ grinding the first element of the rubber bellows, and because the upper sealing surface in a poor smooth form, dynamic friction torque between the ring is greater than the rubber bellows and the shaft between the transmission torque, the relative change in seizures. â‘¢ moving, static ring adjuvant seal because it was sewage in the weak acid, weak alkali erosion, rubber parts have been inelastic. Some have been decadent, lost its due function, the phenomenon of grinding shaft occurred.
　　
(3) In order to deal with the above problems, the following methods are accepted: (1) To ensure the cleanliness of the lower end cap and oil chamber and to prevent the assembly of unclean smooth oil. â‘¡ machine seal oil chamber cavity line should be higher than the dynamic ring sealing surface. â‘¢ According to the different use of medium selection of different structure of the machine seal. High-lift pump should be designed from the new machine structure, the media should be used for aggressive media resistant to weak acid, weak base of fluorine rubber. Machine seal ring should be added to prevent pin.
　　
Second, because of pressure leakage
　　
(1) High-pressure and pressure wave mechanical seal leakage Because the spring pressure and the total pressure than the design is too large and the pressure inside the sealed chamber exceeds 3MPa, will make the seal end surface pressure is too large, difficult to form the liquid film, seal the end face of severe wear , Increased fever, the formation of sealing surface thermal deformation.
　　
Countermeasures: Assembly machine seal, the amount of spring tightening must be carried out according to the rules, do not agree to have too large or too small, high pressure under the premise of the mechanical seal should be accepted. In order to make the end face force reasonable and minimize the deformation, we can adopt the material with high compressive strength such as cemented carbide, ceramic, etc., and enhance the smoothing method of cooling. Select * drive method, such as keys, pins and so on.
　　
(2) the formation of vacuum form mechanical seal leakage pump in the start-up, down process, because the pump inlet infarction, pumping media containing gas and other reasons, there can be negative pressure in the sealed chamber, if the negative pressure in the sealed chamber will be Aroused seal dry friction, built-in mechanical seal leakage (water) scene, the difference between vacuum seal and positive pressure seal is the bias of the object, and the mechanical seal also has a certain bias of its compliance.
　　
Countermeasures: The use of double-sided mechanical seal, which helps to improve the smooth conditions, improve sealing function.
　　
Third, because of media caused by leakage
　　
(1) Most of the submersible sewage pump mechanical seal dismantling, stationary ring and moving ring auxiliary seal inelastic, and some have been decadent, forming a lot of machine seal leakage and even grinding the scene. Because of high temperature, weak acid in the sewage, weak base of the static ring and moving ring adjuvant rubber seal effect of erosion, the formation of mechanical leakage is too large, dynamic and static rubber ring seal information, is not high temperature, acid and alkali , When the sewage is acidic alkaline easy to erosion.
　　
Countermeasures: For aggressive media, rubber parts should be used high temperature resistant, weak acid, weak base of fluorine rubber.
　　
(2) Leakage of mechanical seals due to solid particles Impurities If solid particles enter the seal face, it will scratch or accelerate the wear of the seal faces. The accumulation of scale and grease on the shaft (sleeve) exterior exceeds the wear rate of the friction pair, Moving ring can not compensate for wear displacement, hard on the operating life of hard friction pair than the hard pair of graphite friction pair, due to the solid particles embedded in the graphite sealing ring sealing surface.
　　
Countermeasures: easy access to the position of solid particles should be used tungsten carbide pairs of mechanical friction seal.
　　
Fourth, due to other problems caused by mechanical seal leakage
　　
Mechanical seals also exist in the design, selection, installation, etc. not enough reasonable local.
　　
(1) The amount of spring tightening must be carried out according to the rules of the pump, do not agree to have too large or too small, error ± 2mm, tightening is too large Add pressure on the end face, friction heat too much, forming sealing surface thermal deformation and speed up the end face Wear, tightening is too small dynamic pressure ratio of the lack of end face, you can not seal.
　　
(2) Shaft (or sleeve) of moving ring seal End face and seal of device Static seal The seal gland (or shell) of the pump shall be chamfered and polished to avoid damaging the dynamic ring seal during assembly .
Development history
Early humans were using animal fur to make warm clothing and sleeping mats, which are still used today, including by the Eskimos living near the Arctic. early 19th century explorers and mountaineers began to test different sleeping bag systems, early sleeping bags were filled with camel hair, which has excellent insulation properties, and then a hollow rubber air mattress was invented and used in the 18th century In 1861 Francis Fox Tuckett tested the first Alpine sleeping bag prototype, and in the mid-1860s the envelope sleeping blanket design began to be perfected, and near the ground are hollow rubber coating as a ground thermal insulation layer.
The role of the sleeping bag is simply to keep heat loss to a minimum, while the body inside the sleeping bag is constantly generating heat to keep warm, the amount of heat generated varies from individual to individual and from situation to situation, all sleeping bag temperature calibration systems are based on a standard human body, but such a standard human body basically does not exist. A sleeping body has approximately 75-100 watts of thermal power, which translates into approximately 47-55 watts per square metre based on the surface area of the body. The amount of energy produced by metabolism is very complex and relates to age, gender and even the amount of fat under the body, but by and large a fit young male always produces far more body heat than an older man or woman. The perception of cold is related to age and experience, with novices generally feeling colder than experienced climbers. People who work outdoors a lot feel warmer in cold conditions than those who work in an office a lot.
Use
Whether it is a down or synthetic cotton sleeping bag, try not to compress it up when it is not in use for a long period of time to keep it as fluffy as possible, and it is good to get a proper tan. The purpose of this is to maintain the nature of down and cotton and extend the life of the bag, especially for down sleeping bags, try to keep them in a special down sleeping bag storage bag (loose breathable cotton bag). As a personal hygiene product, try to avoid borrowing each other's sleeping bags.
When using a sleeping bag there are several ways to improve warmth.
Equip a good quality moisture-proof pad, which is very important, as anyone who camps a lot has experienced, if the cold air goes straight from the ground to the back, that kind of cold is unbearable; drink a hot drink before bed if possible, milk and fruit jelly are fine to warm up the body.
Eat a comfortable meal before bedtime, especially with carbohydrates (starches, sugars).
wearing a long set of thermal underwear and clean socks will be very effective.
wearing more clothes when the sleeping bag is not warm enough, or covering the sleeping bag with clothes and other items.
sharing a tent with a larger number of people.
lighting a gas lamp or cooker in the tent if it is safe to do so.
Build a fire. There are so many ways to do this, so try them out when it matters.
Briefly explain the common faults of water pump
 Mechanical seal, also known as the end seal, which has a pair of perpendicular to the torsion axis of the end surface, the end of the fluid pressure and compensation for the mechanical effect of external elastic, rely on auxiliary seal together with the other end of the adherence and relative sliding, and then to avoid fluid Leakage.