【 Weak current College 】 clean room air-conditioning system solutions

<br> <BR> I. Introduction <BR> <BR> 1, clean room air-conditioning system-related specifications <BR> <BR> with the economic development and living standards improve, the current in the electronic, pharmaceutical, food, bio- .engineering, medical and other fields on the increasingly demanding clean room, clean technology also will be developed. .It combines the technology, construction, decoration, plumbing, air purification, HVAC and other aspects of the technology. .In accordance with the People s Republic of standard ' GBJ73-84 " clean room design specifications, the air conditioning system " associated with the major technical indicators: <BR> <BR> A, each level of air cleanliness <BR> M3 ≥ 0.5 micron particles in the air .Number = 0.5 per M3 micron particles in the air a few <BR> 100 level ≤ 35 × 100 <BR> 1000 level ≤ 35 × 1000 ≤ 250 <BR> 10000 grade ≤ 35 × 10000 ≤ 2500 <BR> 100000 grade ≤ 35 × .100000 ≤ 25000 <BR> <BR> B, temperature and humidity <BR> (1) to meet production requirements; <BR> (2) production process without temperature and humidity requirements, the clean room temperature is 20-26 ℃, humidity of the small .at 70%; <BR> (3) persons living with clean rooms and rooms with a temperature of 16-28 ℃. . <BR> <BR> C, <BR> positive pressure clean room clean room must maintain a certain pressure. .Different levels of clean rooms and clean areas and non-static pressure difference between the clean area should be not less than 4.9Pa, clean areas and outdoor static pressure difference, should not be in 9.8Pa.. .<BR> In addition, the air flow, wind speed and other technical requirements. .In short, the indicators between clean and are very strict, therefore, its precise control becomes necessary. .<BR> <BR> 2, the meaning of clean room controlled air conditioning <BR> <BR> in the modern commercial and industrial buildings, equipment, more air-conditioning systems, automation and security management is so important to ensure good operation. .Meanwhile, the general air of total energy consumption over 40% of energy consumption, therefore saving air conditioning energy conservation is an important means. .In terms of clean rooms, even more so. .Controlled use of air conditioning products, will produce the following number of advantages: <BR> <BR> First, since the air conditioning system to automate monitoring, can enable the system to run more secure, and maximize comfort. .Of clean rooms, it became necessary to ensure the production conditions. .In addition, automated controls, you can meet the system and ensure the safe operation of the system, while a variety of technical indicators, the maximum energy-saving control, in line with the increasingly serious energy and environmental needs. .The data indicate that use of controlled air-conditioning system, air conditioning equipment can save 10% of the annual operating costs. .More optimistic estimates suggest that up to 15% -30%. .The controlled air-conditioning products, the total investment in buildings or factories for less than 0.5% of the total investment, return on investment time is short. .Meanwhile, as a result of automatic control and management of equipment, maintenance personnel can be reduced, saving personnel costs, improve management level, to reduce the occurrence of unexpected accidents and equipment damage, leading to potential benefits. .<BR> <BR> 3, clean room air conditioning control system Features <BR> <BR> Excel20 HONEYWELL Chinese version of the controller's advanced Excel5000 American family, a member of the controller. .Particularly suitable for clean rooms such as operating rooms, clean room air-conditioning control, according to "clean room construction and acceptance of," "clean room design specifications should," "mining, ventilation and air conditioning design" and other national standards, and considering the above .The system of internal relations as the core of our Excel20 build a more complete clean room controlled air-conditioning system, which proportional integral control with constant temperature and humidity, indoor remote start and stop air conditioning, indoor temperature setting, the key failure (fire) alarm and associated .Lock, non-critical failure (filter clogging / air heat) alarm and interlock to prevent air condensation in summer / winter frost, the boot sequence and chain, custom start and stop time, program and so on. .<BR> <BR> Second, clean room air conditioning automatic control system constitutes <BR> <BR> 1, analog meters <BR> analog automatic control theory because of its sophisticated control instrumentation, simple structure, low investment, easy to adjust and other factors, in the past .air-conditioning, hot and cold sources and water supply and drainage system has been widely used. .General analog controller for an electrical or electronic, hardware only, no software support. .Therefore, in the adjustment process is relatively simple and put into operation. .Its composition is generally single-loop control system is only applicable to small-scale air conditioning system. .From the development trend, it has been less used, in this no further. .<BR> <BR> 2, the computer control system <BR> sticks due to a computer, control, communications technicians and image technology, the micro-computer control technology in the application of automatic control of refrigeration and air conditioning more and more common. .Traditional control system in the introduction of micro-computer, you can take full advantage of the power of the computer arithmetic, logic and memory functions, the use of computer instruction, the preparation of a compliance control law software. .Computer implementation of these procedures, we can achieve control and management of the controlled parameter, such as data acquisition and data processing. .Control of the computer process can be summarized as real-time data acquisition, real-time decision-making and real-time control of three steps. .These three steps will be repeated continuously so that the whole system in accordance with the laws of a given control, regulation. .It also accused the state variables and equipment operation, fault monitoring, etc., limit alarm and protection, historical data and so on. .It should be said to control functions such as computer-controlled precision, real-time, reliability, etc. are not to be controlled by analog control can not be compared. .More importantly, due to the introduction of computers has brought the management functions (such as alarm management, history, etc.) enhance the analog controller is simply not possible. .Thus, in recent years, automatic control of refrigeration and air conditioning applications, particularly in medium and large air-conditioning systems in automatic control, computer control has been dominant. .<BR> <BR> A, <BR> the so-called direct digital control digital control is a microprocessor in the next move based analog instrument without the aid of the system in which sensors or transmitters, or the output signal directly input to the micro-computer .in, the micro-computer according to the pre-programmed computing direct drive actuators control, referred to as DDC (DirectDigitalControl), this computer is called the direct digital controller, referred to as DDC controllers. .DDC controller's CPU to run fast, and its input to the port configuration (I / 0) as more. .Therefore, it can simultaneously control multiple loops, multiple analog equivalent higher price than features. .<BR> <BR> B, distributed control system DCS TotalDistributedSystem <BR> abbreviated as TDS. .Computer control with the traditional methods, it is decentralized control as much as possible, as centralized management capabilities. .It is from the central station, sub-station, on-site sensors and communication channels connected. .Is the sub-station to the core of the DDC microprocessor controller. .It is scattered throughout the system charged with equipment at the scene, and on-site sensors and actuators directly connected, to achieve the detection and control of field devices. .Central station for centralized monitoring and management functions, such as centralized monitoring, centralized start and stop control, lumped parameter changes, alarm and record processing. .Can be seen on, distributed control system of centralized management by the central station to complete, while the control and regulation by the DDC controller sub-station is completed. .<BR> <BR> Third, clean room air-conditioning and automatic control system to achieve <BR> <BR> 1, <BR> general air purification system, clean room space, the air treatment using the air filter. .Typically, the early installation of filters and effects in the filter efficiency, air cleanliness can reach 10,000. .The requirements for a clean install clean room should be HEPA filter. .In this way, can achieve higher air cleanliness (such as 100 or even higher). .Long-term use of the filter, the filter on the sink with the dust will slowly increase, this will increase the air resistance, affect the entire air conditioning system operation. .Therefore, the projects deal with resistance to change filter the air force of automatic detection and alarm. .Commonly used measurement of differential pressure before and after the filter pressure Pd, and the differential pressure signal for display and alarm limits according to the set pressure for timely and cleaned or replaced. .<BR> <BR> 2, temperature control <BR> <BR> A, a heating control, also known as pre-heating time <BR> heated air is used to heat the fresh air or heating fresh air and a return air mixed wind. .Heat is generally used for a cold winter area, to prevent the fresh air and a mixture of saturated return air to produce water mist or ice. .Heating is also used in a hybrid does not allow a change in clean air-conditioning system. .When using steam or hot water heating, the general control of steam or hot water valve opening to achieve temperature control; when using electric heating, through the thyristor power controller, control the heating electric power to achieve temperature control. .<BR> <BR> B, three heated secondary heating and reheating the control <BR> air cooler is usually located in the table after or after the second return air mixing section. .The purpose of reheating is required in a case of relative humidity, temperature or air conditioning in order to ensure the indoor air temperature. .The control situation with the same heating time. .Into a fine three times the heating and heating, often in high-precision temperature control, fine-tune the settings for temperature of heating. .Its control should be based on the principle of reference to the specific circumstances of implementation. .<BR> <BR> 3, humidity control <BR> <BR> A, wet processing, and control air-conditioning <BR> clean room project, wetting operation is generally in the winter or air dry season, when the transition. .More air humidification method. .Usually steam humidifier and electric humidifier switch control or power regulation. .Steam humidification, depending on humidity control requirements, through the electromagnetic valve position control or two-way control valve with continuous adjustment to achieve. .<BR> <BR> B, desiccant (drying) treatment and control of air-cooled dried <BR> used coolers to complete. .Table of cold air such as the handling of the two wet cooling process. .Coolers were used when humidity control is by adjusting the surface cooler refrigerant (such as frozen water) flow toachieve. .When the humidity is higher than the required value, can increase the cold water valve opening to increase their traffic, to achieve desiccant (ie, drying) treatment; the other hand reduce the flow, to achieve wetting treatment. .Should be noted that, due to the physical properties of air, the humidity control is relatively complex, the method is greater. .Moreover, the air temperature and humidity are two parameters in the adjustment process and interaction. .If for some reason the room temperature, water vapor in the air caused by the saturation partial pressure changes in the absolute case of constant moisture content, relative humidity will decrease. .Therefore, when you adjust a parameter which can also lead to changes in other parameters. .For example, cooler in the summer to dehumidify by adjusting the table, opening a large cold-water valve, in the normal humidity, but also to lower the temperature. .Therefore, in the process design and design automation solutions should take full account of this characteristic. .<BR> <BR> 4, positive control <BR> national standard in China, between different levels of clean room should be larger than 4.9Pa, clean area and should be greater than between the 9.8Pa. .Basic clean room to determine the structure, during operation, maintaining positive pressure can control the amount of fresh air or return air to achieve. .That by controlling the throttle or back to the new throttle opening to achieve. .<BR> <BR> 5, other control and air conditioning rooms in clean energy <BR>, in addition to the technical specifications necessary to ensure the show, some for safety and energy-saving requirements. .Combined with years of engineering practice, have the following main aspects. .<BR> <BR> A, fan failure alarm. .<BR> Fan airflow by detecting the state to determine whether the fan working. .Ruoyin motor burned out or fan belt loose stall and other causes, immediately tothe police. .<BR> <BR> B, Fan <BR> frequency control room to maintain clean and stable pressure or some fresh air / return air ratio, can be machine (motor) Speed implementation of the frequency control. .Proved frequency control throttle opening than simply regulation and control better, but also significantly save power consumption. .Because the air conditioning system, fresh air / return delivery accounted for the largest proportion of energy consumption. .The throttle control is actually through the throttling device (ie throttle) to achieve the airflow changes. .<BR> <BR> C, <BR> pump frequency control of a regulator in a pump system, using frequency control (pump rpm) to achieve flow control than the use of throttling device (ie, regulating valve) is better. .This approach not only in better control, while reflected in the significant savings on power consumption. .<BR> <BR> D, energy-saving program <BR> the application of the computer control system to make energy-saving control a reality. .That in addition to the above-mentioned process characteristics of the air conditioning system controls the implementation of energy saving, the computer control can be achieved, such as enthalpy control, the night cycle, the night wind purification, the best start and stop, zero-energy areas. .Of course, for a particular clean room, its energy-saving procedures should be prepared in accordance with their specific circumstances, to achieve the best energy saving results. .<BR> <BR> Four, air-conditioning control system device configuration <BR> <BR> automatic control system for air conditioning equipment controllers, sensors and actuators. .Mainstream control systems such as the former had to shift from analog to control the computer control, in this, mainly on the realization of direct digital control equipment for both the DDC control brief. .<BR> <BR> 1, DDC controller <BR> Power: 24 <BR> power consumption: 45 <BR> protection standards: <BR> backup battery: 3V lithium battery <BR> LCD: 4 lines × 16 security .Fu <BR> EPROM in a standard procedure in the energy-<BR> Excel DDC controller, is the national standard DCP intelligent substation. .Programming each controller are stored in their memory. .Excel20 i80186 16-bit microprocessor with 16 physical points can be controlled, (you can join the 16 detectors, switches, actuators). .<BR> <BR> It consists of the basic CPU module and power modules as a basis, then any set by software according to the actual needs of the following modules: analog input, and into the module (AL): 7 points, 0 ~ 1VDC, 2 ~ 10VDC ., 420MA; analog output module (AO): 3 points, 210VDC; digital input module (DI): 2 points, dry contact; digital output module (DI): 4 relay outputs; switch the start / stop can be .time schedule to control the when to enable stop; flexible schedule of up to 1 year. .<BR> <BR> 2, temperature sensor <BR> effective temperature range: -20 ℃ to 50 ℃ <BR> maximum transmission distance: 200 meters <BR> environmental requirements: -35 ℃ to 60 ℃, 5% RH to 95 .% RH <BR> electrical wiring: 2 × 1.5MM2, power lines should be shielded <BR> <BR> 3, hot and cold water valves and proportional integral electric drive <BR> valve. .These include: valve V5011, the percentage of properties such as electric valve actuators ML7984 or M7421, matching the different body of chilled water and hot water for the media, DN25-150 for selection of the grid. .<BR> <BR> 4, steam heating / humidification valve and valve drives <BR> V5011, linear features, electric valve actuators M7421, matching the different valve for steam media, DN25-150 specifications for each .selection, 4.6 drive electric throttle, electric new air valve ML6184, damper actuator ML6XXX, ML7XXX, ML8XXX, for 0.75M2-15M2 throttle area, there are switching / intermittent type / continuous choices. .<BR> <BR> 5, the air pressure switch <BR> DPS400 <BR> pressure range :40-400Pa <BR> protection class: IP54 <BR> switching capacity: 1.5A/250VAC <BR> <BR> 6, .air pressure and differential pressure transmitter table <BR> 2000 series micro-differential form: <BR> live show: the pointer display; <BR> measuring range: smallest section of 0-60Pa; <BR> micro-differential pressure transmitter .MODT30 <BR> Range: Min 0-25Pa <BR> output signal :4-20MA <BR> input signal: air pressure <BR> working power :10-35VDC <BR> <BR> 7, other tests, school .<BR> portable digital testing instrument temperature / humidity table 485-1/2: range: temperature -30-85 ℃, humidity of 0-100% RH; Accuracy: Temperature ± 0.5 ℃, the temperature ± 2% RH; power supply: 9V .alkaline batteries; Probe Length: 219mm (485-2 type). .<BR> Portable digital pressure / differential pressure gauge 477 type (with a temperature display): Range: Minimum 0-1000Pa; Operating temperature :0-50 ℃; Accuracy: 50% FS; power supply: 9V alkaline battery; <BR> .Type 471 portable digital anemometer (with temperature display): Range: Minimum 0-1000Pa; working temperature :0-40 ℃; Accuracy: ± 3% FS; supply: 9V alkaline battery. .<BR> Portable particle counters: hand-held, battery-operated; to 0.1FM (cubic feet / minute) calculated 0.3 or 0.5 micron particles; 5 computing model; store data: 200 Group; RS232/RS485 output; Display: 4 lines .LCD, 7 results. .<BR> <BR> <BR>.