Metering and charging the macro energy mainly through three ways: first is to install a flow control valve, the flow balance, and thus overcome the uneven phenomenon; followed by the role of temperature control valve, use of solar energy, free heat home appliances, lighting equipment; third is raised people's awareness of energy saving heat, reduce unnecessary heat open the window. This three energy channels, of which two are realized through the flow control valve. Visible, flow control valve, the metering and charging of the heating system, what occupies an important position. Therefore, how to design the flow control valve is correct, it is very important to.
Electric control valve
Electric control valve is applicable for traffic regulation equipment in computer monitor system. More commonly in unattended use of the thermal station. Electric control valve from the valve body, drive mechanism and a transmitter. Temperature control valve is operated flow regulation device through the temperature sensing packet, no external power supply; and the electric control valve, generally require single-phase 220V power supply, usually as a computer monitoring system of the implementing agencies (adjust the flow). Electric control valve or control valve is the main equipment for regulating the flow of the heating system, the other is the auxiliary equipment.
Balance valve
The balance valve manual balancing valve, self-balancing valve. Whether manual or self-balancing valve balancing valve, and their role is to increase the resistance heating system proximal, restrict the flow of the actual operation should not exceed the design flow; in other words, extra information pressure head and its role is to overcome the proximal end of the heating system, the electric control valve or control valve can work under pressure head at a license. Therefore, manual balancing valve and self-balancing valve, they are temperature control valve or electric auxiliary flow control valve regulating device, but it is very important, if the selection of properly, or the unreasonable design, electric control valve or control valve can not work very well.
Manual balancing valve
Works manual balancing valve
Manual balancing valve is a one-time manual adjustment, can not work with the system automatically changes the status of the drag coefficient, so that the static balance valve. Manual balancing valve effect the object of resistance, can play the role of manually adjustable orifice, to balance the resistance of pipe network system, to the resistance of each loop balancing role. To solve the system steady-state misalignment problem: when the operation is different from the design condition, circulation water is more than or less than the design conditions, the balance valve is the resistance of the system, can be assigned to new content according to the design calculation of the balance, the flow of each branch of the will at the same time scale, still meet the current load the corresponding flow requirements
Attention should be paid to the selection and design of the manual balancing valve problems in the
(1) the valve characteristic curve determines the valve regulating performance, such as the cut-off valve of the flow curve, if that flow changes in 95% ~ 100% between the is of no significance, so opening from 0 to 5%, the full realization of flow, the valve is not as hydraulic condition balance adjustment using. The determination of valve theoretical characteristic curve is the top pressure difference, and the actual condition as long as the valve of the right degree not to 1 valve in the small opening line before and after the valve pressure difference is large, large opening valve before and after the pressure difference is small, the valve dG/dC value increase in the small opening, large opening in the time-varying small, so the valve curve of the actual work to quickly open direction, the valve of the right degree is small and its offset is greater, for linear characteristics of the valve due to offset the actual performance will lead to the effective regulation of the valve opening degree space becomes small, so the valve theoretical curve arc as the percentage of properties such as good. Equal percentage valve characteristic curve, in the valve of the right degree of 0.3 ~ 0.5 working curves could be close to a straight line features.
(2) the valve is usually the valve in the small opening under high flow, vortex area in the valve will be formed in the strong turbulence, scroll areas and the new low pressure, where pressure is lower than saturation pressure temperature corresponding to of water vapor flash steam hammer to play a lead: serious noise, vibration of the valve and pipe, valves, pipe, tube damage. Prevention of such accidents have occurred first in the valve flow channel design considerations valve plug and seat to form the throttle channel narrow in the small opening, bound by strong turbulent vortex formation; secondly, the selection of the valve to increase the valve of the right degree, in order to avoid opening the valve in the small run. In addition, the pressure condition does not involve the issue of balancing valve installed base as low temperature return water pipes.
Self-balancing valve
Self-balancing valve may be in the case of no external power supply, the system automatically flow balance. Self-balancing valve is by keeping the orifice (fixed aperture) must be achieved before and after the differential pressure flow of qualified and, therefore, can be said to flow valve.
Set the role of targeted traffic flow valve, able to lock the water flowing through the valve, and not for the resistance balance. He can solve the dynamic imbalance problem: in order to maintain a single chiller, boilers, cooling towers, heat exchanger, high efficiency operation of these devices, you need to control the flow of these devices are fixed on the ratings; from the system end of the term, in order to avoid dynamic regulation of interaction, also need to limit the flow at the end of the device or branch office.
It should be noted in the design, self-operated flow control valve is the valve has the disadvantage of poor minimum work requirements, the general minimum working pressure product requirements 20KPa, if installed in the most disadvantaged loop, will require that the circulating pump to increase more than 2 m water column of the work head, so the installation should be taken to the proximal, distal disturbing way the. User distance from the heat source radius greater than 80% of heating do not install the self-operated flow control valve.
Temperature control valve
Structure and working principle of the radiator temperature control valve
Temperature control indoor is realized through the radiator temperature control valve. Radiator temperature control valve is from the constant temperature controller, flow control valve and a pair of connectors, of which the core component is the thermostat sensor unit, the temperature package. The volume change can sense changes in ambient temperature, temperature and package, have driven spool valve displacement, thereby regulating the amount of water to change the radiator radiator heat dissipation. Thermostatic valve set temperature can be artificially adjusted, thermostatic valve will automatically control and adjust the radiator set according to requirements of water, so to achieve the purpose of indoor temperature control. Temperature control valve is generally installed in the radiator before, by automatically adjust the flow, the residents need to achieve room temperature. Temperature control valve with two temperature control valve and the three temperature control valve branch. Three temperature control valve is mainly used for single-tube system with cross tube, the shunt coefficient in the 0 to 100% range, flow control room for large, but the price is more expensive, more complex structure. Two temperature control valve for two-pipe system, and some for single-tube system. For the two temperature control valve resistance two-pipe system large; for single pipe system resistance. Temperature control valve temperature sensing packet and assembled into a whole body in general, temperature of the scene itself is an indoor temperature sensor. If necessary, you can use a remote temperature sensor; remote temperature sensor placed in temperature controlled room, a portion of the valve body placed in a heating system.
Thermostatic valve of the type design
Temperature control valve is the main equipment of heating regulation system flow regulation, other auxiliary equipment control valve is, so temperature control is essential. A heating system if you do not set the temperature control valve that can not be termed a heat metering and charging system. In the temperature control valve design, the correct selection is very important. The purpose of temperature control valve selection, is based on the design flow (a known heat load), allowing to determine the pressure drop of KV value (flow coefficient); and then by the KV value to determine the temperature control valve diameter (model). Therefore, the design drawings or manufacturers must be given the sample value KV and the diameter of the relationship, or does not facilitate the design personnel.
The thermostatic valve of the type design, is by no means a simple selection and pipeline control valve of the same caliber is over. But in the selection process, the thermostatic valve to the selected pressure caused by an ideal working conditions. A thermostatic valve is usually the work of pressure in the 2 ~ 3mH2O between, a maximum of not more than 6 ~ 10mH2O. Therefore, we must give thermostatic valve pre-set range of values, in order to prevent noise, affect the temperature control valve work. When the same KV values, there are more than two kinds of caliber options, priority should be to choose a small-caliber valve, its purpose is to improve the adjusting performance of temperature control valve.
Differential pressure regulating valve
Principle of differential pressure regulating valve
Principle of differential pressure regulating valve, essence and self-balancing valve is the same. Only self-balancing valve, the orifice plate as a component exists in the body in; and there is no differential pressure regulating valve in the orifice of the parts, but the system differential pressure regulating valve as a back plate, therefore, the differential pressure regulating valve value actually refers to the system pressure difference between import and export. From the differential pressure regulating valve structure can be seen: This valve to control the system, the pressure difference between import and export fixed. Basic function is based on heat load heat demand for the user operation, automatically adjust the flow of heat users. When a building, due to lower temperature and some hot user requirements, the corresponding room temperature control valve open for smaller, resulting in differential pressure regulating valve of the pressure difference between the larger, more than the set value, the automatic pressure regulating valve off a small spool, increasing the throttling effect, so that the value of the system pressure decreases, until the restore settings. The net effect is to reduce the flow, heat required to meet the thermal requirements of users, frequent operation to reduce the temperature control valve. User requirements to improve room temperature heat, pressure regulating valve of the opposite effect.
In the design should pay attention to the problem
Some people think that in the indoor system, or riser, the pressure regulating valve should be installed. After simulation: if the heat in the building entrance, unified balancing valve installed (including manual, self-operated) or pressure regulating valve (but the design must be reasonable), the indoor temperature control valve within the scope of any regulation, the pressure before and after difference is no more than 6 ~ 10mH2O, the temperature control valve can be in reasonable under the condition of. Therefore, too much to install a pressure regulating valve is not necessary, it is not economical.
Circulating pump variable flow operation, the flow control valve selection
Here mainly refers to the manual balancing valve, self-balancing valve and pressure regulating valve selection. Circulating pump variable flow operation, manual balancing valve geometric disorder, the most conducive to the operation of temperature control valve; but its drawback is that manual too much, it is difficult to achieve the desired adjustment. Circulating pump variable flow operation, the heat users the most ideal entrance pressure value should be set with the outdoor temperature changes. For this point, self-balancing valve, differential pressure regulating valve, are not ideal, but it will not be regulated out of control. So using this type of control valve, which is beneficial to improve the regulation of heating system performance is.
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