ABSTRACT: This paper summarizes the main monitoring contents of clean operating room in intelligent hospital, puts forward some new concepts of monitoring system design, and presents the principle block diagram of a three-level structure monitoring system based on PROFIBUS. Through precise control of the parameters in the operating room, it can provide safe, comfortable and efficient work for the operating department. The environment also effectively solves the problem of energy saving.
Key words: clean operating room; monitoring content; monitoring system
Clean operating room is the symbol of intelligent hospital. Modern hospitals have clean operating room, which is composed of clean operating room, purification ward and other auxiliary rooms. Clean operating room often uses filters to circulate and filter indoor air, organize airflow reasonably, establish scientific human, logistics process and strict zoning management, so as to achieve the goal. The temperature, humidity, pressure, air intake and air cleanliness in the operating room should be tested and controlled in order to ensure the reliable operation of the equipment and reduce energy consumption, so as to provide a comfortable, safe and efficient working and living environment for the operating department.
1. Main Monitoring Contents of Clean Operating Room
1.1 Indoor Temperature
According to the technical specifications for clean operating rooms in hospitals, operating rooms at all levels (especially clean operating rooms, standard clean operating rooms, general clean operating rooms and quasi-clean operating rooms) require temperatures of 22-25 [1]. However, in practical application, the set temperatures often need to be controlled between 18-25 [2]. Usefulness, setting temperature should be adjustable artificially.
1.2 Indoor Humidity
Relative humidity of special clean operating room and standard clean operating room is 40%-60% in the specifications. Relative humidity of general clean operating room and quasi-clean operating room is 35%-60%, and priority control of humidity is emphasized. Relative humidity of indoor is a certain range, but the objective parameter of system control is designed. The reason is that when the relative humidity is 50%, the bacteria in the air will die after 10 minutes of plankton, and when the relative humidity is higher or lower, most bacteria will still live even after 24 hours, that is to say, 50% of the relative humidity in the air is the best. Humidity can also be adjusted artificially.
1.3 Indoor Pressure
Specifications require that special clean operating rooms and standard clean operating rooms maintain a minimum static pressure difference of +8 Pa for adjacent low-level clean rooms, while general clean operating rooms and quasi-clean operating rooms maintain a micro-pressure difference of +5 Pa. For areas directly connected outdoors, a micro-pressure difference of not less than +15 Pa and a maximum static pressure difference of not more than +30 Pa should be maintained. If the operation room is contagious and clean, the corresponding micro-negative pressure should be maintained outside.
1.4 Indoor Fresh Air Volume
Clean operating room should meet the fresh air volume of 60 m3/h per person and ventilate 4-6 times/h, at the same time, it should compensate the indoor exhaust and keep the indoor micro-positive pressure. It should not be less than 1 000 m3/h for special clean operating room, 30-36 times/h for standard clean operating room and no less than 800 m3/h for general clean operating room, 18-22 times/h for ventilation. It has no less than 800 m3/h, 12-15 times/h ventilation in the quasi-clean operating room and no less than 600 m3/h. Fresh air ratio is 10%-25%, and the obstetric delivery room is fresh air.
1.5 Planktonic Bacteria
The maximum average concentration of planktonic bacteria is 5/m3 in the special clean operating room, 25/m3 in the standard clean operating room, 75/m3 in the general clean operating room and 175/m3 in the quasi-clean operating room, and the maximum surface contamination density is 5/cm3. In addition, there are operating preparation room, articles storage room, nurses'station, anesthesia room, dressing room and cleaning room. Control of temperature and humidity, micro-pressure difference, fresh air volume, maximum average concentration of planktonic bacteria and noise in net corridor etc.

The main monitoring contents of the clean operating room are shown in Table 1

2 Design Concepts
1) Electric airtight valves are installed on the circulating air supply, return air and exhaust ducts of each operating room. [3] When the air conditioning system of an operating room stops running, the corresponding electric airtight valves are closed in time to prevent the operating room from being polluted. Scientific air filtration system is set up, reasonable selection of filtering mode and general high-level air supply to the operating room is adopted. A three-stage filtration system is adopted. The return air is pressurized by the primary filter fan, filtered by the intermediate efficiency filter, and finally filtered by the last high efficiency filter. The fresh air is filtered by the initial and intermediate efficiency two levels. The pressure difference between the two sides of the filter is monitored, and the blockage alarm of the medium efficiency and high efficiency filter is given.
2) Air-conditioning displacement ventilation system. Compared with traditional ventilation mode, displacement ventilation strengthens the purification function and highlights the energy-saving effect. The core of displacement ventilation is the technology of fresh air exchange. It is a kind of technology that filters, purifies and heat exchanges outdoor fresh air into the room, and at the same time filters and purifies indoor polluted harmful gases. It is an efficient, energy-saving and environmentally friendly ventilation way to discharge out of the room after treatment and control the indoor temperature and cleanliness.
3) During the normal working period of the operating department, the air conditioning unit and the fresh air unit operate simultaneously. When the operating department only works in part of the operating room, only the independent air conditioning unit and the fresh air system in part of the operating room need to be operated, which not only guarantees the normal operation of part of the operating room, but also guarantees the normal pressure distribution and directional flow of the whole operating department.
4) The independent exhaust fans of each operating room are interlocked with the automatic door of the operating room, and frequency converters and delay devices are set up. The exhaust fans stop immediately when the door is opened, and then open the exhaust fans after closing the door and establishing positive pressure. This not only ensures that the positive pressure is maintained when the door is opened, but also avoids frequent start and stop of the exhaust fans due to opening and closing the door. The air volume of the machine can be controlled by the frequency converter to maintain the indoor pressure at normal level.
5) Independent fresh air unit control, using static pressure to control the fan frequency conversion, adjust the air volume, in order to achieve the purpose of energy saving. Fresh air unit and air conditioning unit interlock, only start the fresh air unit first can start the operating room air conditioning units. As long as one operating room is working, fresh air system will continue to operate, only in the whole operation. Fresh air units are not shut down until the unit is closed.
6) Fresh air units and circulating air conditioning units adopt a set of digital controllers to control temperature, humidity, primary and secondary return air volume, water valve opening, and monitor and alarm parameters such as pressure difference before and after filters. The operating room is equipped with a general controller, which is interlinked with air conditioning units, exhaust fan units and fresh air units. Indoor air parameters are set on site.
7) The central monitoring and management mode is adopted to control the start-up, operation and shutdown of air conditioning units and fresh air units so as to achieve the goal of energy saving on the premise of meeting the requirements of various parameters.
3 system design
Temperature, humidity, pressure and cleanliness in a clean operating room are controlled by purifying air conditioning units. [4] The control system needs to automatically adjust the parameters of the operating room after real-time data collection, storage and statistical analysis, so as to realize the optimal control and management of the whole system and make the operation and management of the equipment more efficient. The core object of the monitoring system is the air conditioning unit and fresh air pretreatment unit in the operating room. The system design should conform to the strong universality, easy maintenance and management. After each equipment is put into operation, it can be guaranteed to be continuously opened. It has the functions of "automatic" and "manual", and implements decentralized control and centralized supervision. See principle.
3.1 Real-time monitoring of temperature, humidity and micro-pressure difference in operating room
According to the actual needs, monitoring points are set up in the operation department, and corresponding temperature, humidity or pressure sensors are arranged in each monitoring point to monitor the main parameters (temperature, humidity, pressure), filter status, operation status and failure status of each purification air conditioning unit in real time.
The temperature sensor monitors the temperature of heater inside the unit, alarms for overtemperature and interacts with related equipment in parallel, monitors the surface temperature of coil intake side, and automatically switches the control mode according to seasonal variation.
Monitor the pressure difference between the coil and the electric heater. Close the cold/hot coil and the electric heater without air flow passing through the unit.
The monitoring system can adopt three-level structure of management level, monitoring level and process control level. The system structure block diagram is shown in Fig. 1 [5].
3.2 Automatic adjustment of temperature and humidity in operating room
Temperature and humidity are regulated by the opening of refrigeration, preheating, heating and humidifying valves; the opening of two-way regulating valves of heating coil and surface cooling coil is controlled according to the return air temperature; and the opening of steam humidifying valve is controlled according to the return air temperature, so as to control the temperature and humidity of operating room as a set value. Electric regulation of cold and hot water is provided accordingly. Valves and their actuators and humidifying solenoid valves for controlling humidification amount.
Because the air in summer is generally high temperature and humidity, it can be cooled and dehumidified in the supercooled section first, then heated to meet the requirements of temperature and humidity. In winter, the air is generally low temperature and dry, then heated and humidified first. In spring and autumn, fresh air outside can be used as much as possible.
3.3 Automatic regulation of micro-positive pressure in operating room
According to the indoor environmental pressure, frequency conversion constant air pressure control is realized by using frequency converter, which is realized by controlling the wind speed of frequency conversion fan and exhaust fan and changing the air volume. It is necessary to monitor and control the operating frequency of the air supply fan and exhaust fan, monitor the air pressure at the air supply outlet and exhaust outlet, and set up the air duct pressure sensor accordingly.
The principle block diagram of the unit control system is shown in Fig. 2. The monitoring system should also be scalable and can be easily incorporated into the building automation system (BAS) of the whole intelligent hospital as a subsystem.
4 Concluding remarks
By using advanced computer control technology and management software, we can scientifically control and manage the mechanical and electrical equipment in the clean operating room, accurately stabilize the temperature, humidity and pressure of the operating department at the set value, thus reducing the labor intensity of the staff, effectively solving the problem of energy saving, saving the workload and operation of maintenance and management. The problem of operating expenses. Intelligent management of medical equipment in clean operating room of intelligent hospital is still lack of mature experience, and some problems are still under discussion.
Reference:
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[2] Zhang Xianghong. Intelligent system design of hospital clean operating room [J]. Intelligent building and city information, 2003, (3): 16-19.
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Shandong Aide Purification Engineering Co., Ltd. has strong technical strength and construction experience, according to the different needs of clean places, using professional equipment, to form different levels of clean standard space, to create the most suitable production and working environment. At present, it has established close cooperation with many enterprises and is a trustworthy professional purifying project implementer. Wechat Public Number: Aide-188