Heaters vvpi combine the advantages of shell and tube and plate heat exchangers. 1.Podogrevateli vvpi, like most shell and tube units, designed to meet the requirements on the strength of gost 14249-89 "Vessels and apparatus. For even more details, read what Investment opportunities says on the issue. According to Energy Capital Partners, who has experience with these questions. Limits and methods of strength calculation ", gost 25859-83 'steel vessels and apparatuses. Limits and methods of strength calculation for low-cycle loads ', rd 26-14-88' vessels and apparatus. Energy Capital Partners may find it difficult to be quoted properly. Limits and methods of strength calculation. Elements of heat exchangers devices'.
Ie Heaters vvpi not falling within the characteristic 'Pressure vessels' nevertheless made to meet the requirements of the vessels increased risk. Cruising on the strength of the elements body with respect to the nominal permissible stress according to gost 1429-89 – 350 400%. Cruising on the strength of the tubes – 1000 1500%. In connection with this heater vvpi not sensitive to sudden temperature fluctuations and pressure. Tube bundles withstand hydroblows, vibration, etc. In general, it provides high reliability heaters vvpi including in terms of possible violations of operation modes. Such categorically unacceptable for operation plate heat exchangers.
Plate heat exchangers are not designed to meet these regulations and have a much smaller margin. Manufacturers of plate apparatus always indicate restrictions on the rate of change of pressure and temperature, noted the impossibility of operating in the presence of water hammer. 2. Intensification of heat transfer in the heaters vvpi and plate apparatus is about the same and 200 250%. However, in the heat exchangers vvpi and plate heaters used the same principles of intensification of heat transfer.
In modern meat processing plants, large grocery stores are widely used band saws. Band saws used for cutting into pieces of fresh and frozen meat, bones, fish and poultry gradually replacing the butcher, who chops the old-fashioned meat toporom.V currently in a serious enough competition in the market of food, important also look the goods offered will be proposed purchaser. Agree that neatly sliced meat on the saw looks much aesthetic than chopped with an ax. Bandsaw cuts the meat gently, smoothly, without any fragments of bone and without weight loss. Meat cutting saw takes much less time than logging. The saw easier to separate the more valuable parts of the carcass from less valuable. Finnish band saws are manufactured by the original technology, developed by ct, and may have the following performance: * with movable table * fixed table. * All equipment is working quietly with minimal vibration.
* Equipment can be easily disassembled for cleaning. Band saw comes fully ready to work. Little dwell in safety, as well as on those elements of saws, which are needed for this: * cutting on the saw must be performed quickly and rhythmically. * Do not try to exert physical effort for the product, allow the canvas saw to make this work. * The operator will not work more safely and efficiently, if he tries to apply the product to the leaf faster than the saw can cut. * When sawing, always place the bottom edge of the upper Lock the saw blade as close as possible to cut the product in this case, the cutting process is more accurate, moreover, is not protected only a small area saw blade immediately necessary sawing.
As a result of uneven heating of the metal concentrated source of heat in a welded structure having welding voltage – time and residual. Temporary welding voltage are valid only during the period welding when the temperature of welded metal. Voltage remaining in the metal after welding and complete cooling design, called the residual welding stresses. They arise from constrained thermal expansion and constrained shrinkage of metal during its heating and cooling. This constraint is due to the fact that the locally heated area of welding on all sides surrounded by the cold metal.
Additional fixing the workpiece (in the adaptation, with rigidly fixed) also interferes with normal processes of thermal expansion and shrinkage, and there are reactive residual stresses. When welding alloys with polymorphic transformations in parts of the welded joint metal, heated above the critical point, there are structural stresses. For example, when welding hardenable steels, heat-affected zone which martensite is formed with a large volume effect of transformation, the structural stresses reach high values. Distinguish three types of welding voltage. In welded structures of carbon and low-alloy steels are driven primarily by welding voltage of the first kind.
They are balanced and in amounts commensurate with the size or design of its individual parts. Welding voltage of the second and and third kinds are balanced within the microvolume and the individual grains of the metal. Depending on the direction of action in space distinguish welding voltage linear, or uniaxial, acting only on one axis, planar, or two-axle, acting in two mutually perpendicular directions, volumetric, or three-axle, acting in three mutually perpendicular directions. Direction of the action with respect to the axis cross stitch welding voltage different from the longitudinal. Technology, assembly and welding of structures should be tailored to ensure that the minimum values of welding voltage and when it is dictated by terms of design, include the removal of these stresses. If the values of welding stresses reach the yield point of the metal, then there is its plastic deformation, ie change the size and shape welded construction, called the warp. Arising during welding deformation is divided into time to develop only during the welding of the structure, and residues that remain after the welding and cooling design. Depending on the nature, form and size of the workpiece residual welding deformations are developed "in-plane" and go "out of the plane" of connected elements. Deformation "in the plane" appears in Change (decrease) the size of design, with what must be considered when cutting parts and assembly welding, providing allowance for resizing. Deformation "of the plane (angular deformation) occurs in Education bulge (hlopunov "), the local bending of sheets, the so-called mushroom bending zone during welding of elements of T-and I-sections, as well as other changes in forms of products. The magnitude and nature of residual strains are highly dependent on the thickness and properties of base metal, welding conditions, weld shape, consistency of their performance, design of welded parts. In developing the technology and build weld design should aim to reduce the residual strain. If the value of residual strain goes beyond tolerance, it involves editing the structure.
The economic effect of the introduction into the production process of electric motors and frequency inverters soft starters (soft starters) is achieved by the following factors: energy savings in pump, fan and compressor units up to 50% – 60% due to capacity control by changing the motor speed as opposed to regulation of way on / off, etc.; increase product quality, increasing the volume of production and productivity of manufacturing equipment, increasing the service life of process equipment due to the improvements of the dynamics of elektroprivoda.Pri choosing the model of the frequency converter should be based on a specific task, which should solve the actuator: type and capacity of the electric plug, accuracy and range of regulation speed, accuracy to maintain torque on the shaft of the motor design (dimensions, weight). When you work with a standard induction motor inverter should be selected with the appropriate capacity. If you need a great starting point or a short acceleration / deceleration time, select the frequency converter is a step above the standard. Examples of specific application of the frequency elektroprivodNa water pumping stations: The frequency converter is installed between the supply network and an electric motor to provide feedback. In the pressure manifold at the outlet of pump unit installed pressure sensor. Smooth regulation of frequency converter and the high accuracy of pressure in water supply networks can save energy up to 60% and leads to savings of pumped water, essentially eliminates hydroblows increasing the service life of pipes and valves.
Oil heater type pmt, developed by the design bureau, Thermal Engineering Institute of rao ues Russia. Especially for the gas-fuel oil sector, taking into account all of shortages heaters oil past models, instead of morally aged heaters model pm, pbr and their changes. At the moment, this technique is very even, successfully used in subdivisions of rao, metallurgical, Railways and other areas of the industry both in Russia and in neighboring countries. More than 10 years of experience in manufacturing heaters range itp + proven technical and operational "victory" in the model range. In heaters type pmt, used the technology of the turbulent flow.
They are all fitted with blocks of turbulent parts, thus, the effectiveness of the thermal energy of steam, increases in 2,5-3 times by reference to available models of heaters. Oil heaters range pmt (turbulent), will provide heating oil to 150. C of from 1 to 150 t / h. The total mass heaters itp is much lower mass heaters, such as performance, produced in particular tcd, which greatly simplifies maintenance and repairs. Normal heater pmt, 30-40 weight, which is only 1.3 tons. In particular, for inclusion in the operation of oil heaters, we must not less than 1-1,5 hours to their gradual warming. When connecting the heater pmt in operation, preheating is not necessary to perform. As is the practice at a low cost of fuel oil through the heater, which very often the point at thermal power plants, but on the inside "area" of pipes must be organized deposits, because of the small rapidity of flow of fuel oil in them, resulting in sharply reduced effectiveness of heat transfer. The proposed schematic diagram, use our heaters there is likely to disconnect, a part of the heaters. And because of this support in the past, we have heater, the desired speed of movement of oil in the pipes, so as to exclude the possibility of sediment.