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Working principle of closed cooling tower cross flow, counter flow and open cooling tower


Release time:

2018-07-11

MSTNB Series-Closed Cooling Tower (Countercurrent) 1. Working Principle The air inlet form of NB Countercurrent Cooling Tower is bottom countercurrent air inlet, which alternately forms saturated hot and humid air in reverse with falling spray water. The heat is discharged by the top fan, and the water is blocked back to the water collection tank by the special structure dehydrator for circulation. There is no filler for pre-cooling and heat dissipation in the internal space, and more space is left to increase the unit heat dissipation area of the coil, small footprint. It is especially suitable for fluid cooling with low temperature or small temperature difference. MSTNB concept: MST-MUST refrigeration N-counterflow B- closed system 2, complete set of components

MSTNB Series-Closed Cooling Towers (Counterflow)
1. Working principle
The air inlet form of NB counterflow cooling tower is bottom counterflow air inlet, which alternately forms saturated hot and humid air in reverse with falling spray water. The heat is discharged by the top fan, and the water is blocked back to the water collection tank by the special structure dehydrator for circulation. There is no pre-cooling and heat dissipation filler in the internal space, and more space is left to increase the unit heat dissipation area of the coil. The structure is compact and the area is small. It is especially suitable for fluid cooling with low temperature or small temperature difference.
MSTNB Concept: MST-MAGINTE Refrigeration N-Counterflow B- Closed System
2. Components
Complete sets of equipment generally have three major components: host, auxiliary, electric control box;
Host components:
1) Fan: The design of induced air type air cylinder conforms to the principle of aerodynamics, makes full use of the theory of homogenization of gas flow field, reduces the vortex area, reduces the flow resistance, and enables the hot air in the machine body to be quickly discharged out of the machine;
2) Water collector: The main function is to block the discharged water to the maximum extent. When the equipment is in normal operation, the lower spray pump sprays a large amount of water on the copper pipe. As the upper part is relatively close to the position of the fan, in order to prevent some water from being sucked out of the machine by the fan, the water collector needs to block it;
3) Cooling coil (condenser): generally, it can be made of two materials: a, it is welded with high-quality T2 red copper tube, with pressure resistance design of 1.6Mpa, and the heat dissipation effect of copper tube is relatively good. it is generally used in medium frequency furnace industry, cold storage (food), chemical industry, etc. B, made of high-quality low-carbon seamless steel pipe, after classification and three times of 2.5Mpa strong pressure test, the whole is carried out zinc immersion treatment in a high temperature tank, to ensure the excellent performance of the steel pipe, the general application in the central air conditioning (screw unit) industry.
Note: the cooling coil cooling fluid can be a variety of, such as pure water, quenching fluid, hydraulic oil, liquid ammonia, freon, etc;
4) Water collection tank: mainly contains a certain amount of water source (usually ordinary tap water), so that the spray pump water circulation is ensured when the spray device is working, so that the water sprayed from the spray pump to the cooling coil naturally falls into the water collection tank, thus ensuring the normal operation of the spray process.
5) Spray head: in order to make the water sprayed onto the cooling coil evenly and smoothly, to achieve the best heat dissipation effect;
6) Sprinkler pump: The main function is to evenly spray the water in the sump to the cooling coil through the pipeline and the sprinkler head. When a large amount of water sprayed by the sprinkler pump flows from top to bottom, it will take away a part of the heat from the cooling coil to achieve the purpose of cooling;
7) Air inlet grille: waterproof splash, dust prevention, direct sunlight prevention, large air inlet, small wind resistance, reduced fan energy consumption, and there will be no spray water splash phenomenon, avoid sunlight to the inside of the sink, effectively ensure the spray water quality and use temperature, effectively prevent dust and algae breeding;
8) Cooling tower shell: support, the main component of the body; made of aluminized zinc plate, it is one of the most corrosion-resistant and heat-resistant plates, and its service life is 3-6 times that of ordinary galvanized plates; according to special needs, it can also be made of 201, 304 or 316 stainless steel plates.
Auxiliary components:
1) Stainless steel water tank: mainly holds the circulating fluid to be cooled. The circulating fluid is closed, but there is still a small amount of loss. The level gauge automatically measures and alarms to supplement the cooling fluid (coolant) in time;
2) Circulating water pump: It is closely connected with the stainless steel water tank, so that the stainless steel water tank fluid enters the cooling coil of the host for circulation through the action of the circulating water pump, enters the equipment to be cooled, and then flows into the stainless steel water tank after the equipment comes out, so as to realize the corresponding The purpose of rapid circulation of the fluid;
Electric cabinet part:
1) Automatic digital display temperature control system: this system can set the upper limit temperature. when the actual temperature measured from the thermal resistor is higher than the set upper limit temperature, the system can automatically start the next program or alarm. For example, the temperature of the cooling fluid to be entered by a device shall not be higher than 40 ℃, so the upper limit temperature set on the temperature control system is 40 ℃, in order to reduce the operating cost, for the two cooling methods of the cooling equipment (spray pump, fan), only one method can be started. When the thermal resistance is measuredWhen the actual temperature is higher than 40 ℃, one mode will be automatically started, and the two modes will start to work at the same time, so as to achieve the best cooling effect. If the actual temperature is still higher than the set temperature when both modes are started, and the alarm device has been triggered, it means that the temperature of the spray water in the lower water collecting tank is also very high, and the effect of the spray water taking away heat has not been achieved, the water in the sump can be replaced;
2) Automatic control system of spray pump;
3) Fan automatic control system;
4) Circulating water pump control system;
5) Automatic liquid level alarm system;
6) High temperature automatic alarm system;
Calculation method of control power line: DC current × 0.816 ÷ 2.5
3. Selection of MSTNB series in casting, forging and heat treatment industry (medium frequency electric furnace)
For the use of medium frequency electric furnace equipment in the industry, generally in accordance with the medium frequency electric furnace power selection;
Medium frequency electric furnace equipment is generally divided into two parts: power supply and furnace body:
The calculation formula for cooling a full set of medium frequency electric furnace equipment is: power * 0.45*860 = cooling capacity (Kcal/h)
For cooling only the power part, the calculation formula is: power * 0.15*860 = cooling capacity (Kcal/h)
For cooling only the furnace body part, the calculation formula is: power * 0.35*860 = cooling capacity (Kcal/h)
Note: 0.45, 0.15, 0.35 and 860 are all constants. Refer to the following parameter table for cooling capacity parameters
For example: a set of 400KW medium frequency electric furnace water circulation part, need to buy FBN closed cooling tower full set of equipment cooling, according to the above formula:
400KW*0.45*860=154800Kcal/h
According to the similar values in the following parameter table, the model of closed cooling tower is MSTNB-30.
MSTHB Series-Closed Cooling Towers (Cross Flow)
1. Working principle
The working fluid (water, oil or other liquid) flows in the coil. The outer wall of the coil is wrapped by spray water. The heat of the fluid is transferred through the pipe wall and forms saturated humid and hot steam with water and air. The heat is discharged into the atmosphere by the fan, and the water is blocked back to the water collecting tank for circulating spray. The spray water reduces the water temperature through the PVC heat sink during the circulation process and forms the same flow of wind and water with fresh air, the coil mainly relies on sensible heat conduction, and the important feature of this operating principle is to suppress the scale generation on the outer wall of the coil. Especially suitable for high temperature fluid (such as 80 or more) or cooling temperature difference (such as 60-35) fluid cooling.
MSTHB Concept: MST-MASHINTE Refrigeration H-Cross Flow B- Closed System
2. Components
Complete sets of equipment generally have three major components: host, auxiliary, electric control box;
Host components:
1) Fan: The design of induced air type air cylinder conforms to the principle of aerodynamics, makes full use of the theory of homogenization of gas flow field, reduces the vortex area, reduces the flow resistance, and enables the hot air in the machine body to be quickly discharged out of the machine;
2) Heat dissipation filler: the heat dissipation filler is hung on the air inlet side of the tower in pieces for cooling by spraying water. It is made of hard vinyl chloride resin (PVC) plate, which is flame retardant, the plate body is specially embossed, and the liquid baffle plate is integrally formed at the edge of the inner side (fan side). Maximize the heat exchange performance of water and air, and control the amount of water scattering to a minimum. And durable, strong resistance to high durability.
3) Cooling coil (condenser): generally, it can be made of two materials: a, it is welded with high-quality T2 red copper tube, with pressure resistance design of 1.6Mpa, and the heat dissipation effect of copper tube is relatively good. it is generally used in medium frequency furnace industry, cold storage (food), chemical industry, etc. B, made of high-quality low-carbon seamless steel pipe, after classification and three times of 2.5Mpa strong pressure test, the whole is carried out zinc immersion treatment in a high temperature tank, to ensure the excellent performance of the steel pipe, the general application in the central air conditioning (screw unit) industry. Note: the cooling coil cooling fluid can be a variety of, such as pure water, quenching fluid, hydraulic oil, liquid ammonia, freon, etc;
4) Water collection tank: mainly contains a certain amount of water source (usually ordinary tap water), so that the spray pump water circulation is ensured when the spray device is working, so that the water sprayed from the spray pump to the cooling coil naturally falls into the water collection tank, thus ensuring the normal operation of the spray process.
5) Spray head: in order to make the water sprayed onto the cooling coil evenly and smoothly, to achieve the best heat dissipation effect;
6) Sprinkler pump: The main function is to evenly spray the water in the sump to the cooling coil through the pipeline and the sprinkler head. When a large amount of water sprayed by the sprinkler pump flows from top to bottom, it will take away a part of the heat from the cooling coil to achieve the purpose of cooling;
7) Air inlet grille: waterproof splash, dust prevention, direct sunlight prevention, large air inlet, small wind resistance, reduced fan energy consumption, and there will be no spray water splash phenomenon, avoid sunlight to the inside of the sink, effectively ensure the spray water quality and use temperature, effectively prevent dust and algae breeding;
8) Cooling tower shell: support, the main component of the body; made of aluminized zinc plate, it is one of the most corrosion-resistant and heat-resistant plates, and its service life is 3-6 times that of ordinary galvanized plates; according to special needs, it can also be made of 201, 304 or 316 stainless steel plates.
Auxiliary components:
1) Stainless steel water tank: mainly holds the circulating fluid to be cooled. The circulating fluid is closed, but there is still a small amount of loss. The level gauge automatically measures and alarms to supplement the cooling fluid (coolant) in time;
2) Circulating water pump: It is closely connected with the stainless steel water tank, so that the stainless steel water tank fluid enters the cooling coil of the host for circulation through the action of the circulating water pump, enters the equipment to be cooled, and then flows into the stainless steel water tank after the equipment comes out, so as to realize the corresponding The purpose of rapid circulation of the fluid;
Electric cabinet part:
1) Automatic digital display temperature control system: this system can set the upper limit temperature. when the actual temperature measured from the thermal resistor is higher than the set upper limit temperature, the system can automatically start the next program or alarm. For example, the temperature of the cooling fluid to be entered by a device shall not be higher than 40 ℃, so the upper limit temperature set on the temperature control system is 40 ℃, in order to reduce the operating cost, for the two cooling modes (spray pump and fan) of the cooling equipment, only one mode can be started. When the actual temperature measured by the thermal resistance is higher than 40 ℃, one mode will be automatically started. The two modes will start working at the same time to achieve the best cooling effect. If both modes are started, the actual temperature is still higher than the set temperature, and the alarm device has been triggered, it means that the temperature of the spray water in the following water collection tank is also very high, and the effect of the spray water to take away heat cannot be achieved. The water in the water collection tank can be replaced;
2) Automatic control system of spray pump;
3) Fan automatic control system;
4) Circulating water pump control system;
5) Automatic liquid level alarm system;
6) High temperature automatic alarm system;
Calculation method of control power line: DC current × 0.816 ÷ 2.5
MSTNK Series-Counterflow Open Cooling Towers
NK series-counter-current open cooling tower has the following disadvantages compared with NB series-closed cooling tower: 1. It occupies a larger area and has a larger noise (closed tower adopts a low-noise fan with less noise);
2. Large amount of water supplement (the amount of water to be supplemented every day in summer is 1/3 of the total amount of water in the cooling tower);
A large amount of water vapor evaporates, taking away good water molecules and reducing water quality;
4, easy to enter impurities, rain, etc., easy to produce scale, and difficult to clean;
5. The cooling effect is relatively poor (it can reach 41 ℃ in summer, and the closed tower can guarantee 30-32 ℃)
MSTNK series-countercurrent open cooling tower relative to MSTNB series-countercurrent closed cooling tower its working principle is basically similar, the difference is that NK series-open cooling tower without cooling coil, which for the use of open tower in various industries has been greatly restricted; but open tower relative to the closed tower investment cost is small.