The purpose of invalidating the above-mentioned electri […]
The purpose of invalidating the above-mentioned electrical devices is that when the elevator speed limiter and safety gear act or the elevator car squats to the bottom or rushes to the top, the emergency electric operation switch can be used to conveniently, quickly and safely drive the elevator to the leveling position to make the ride The personnel leave the elevator safely. Since the permanent magnet synchronous gearless drive main engine is commonly used in machine room-less elevators, if it is directly operated by disc wheels, the operating force must be greater than ". In addition, even if the gear-driven main engine is used, manual emergency operation is not as convenient as machine room operation. Therefore, no The elevator in the machine room should be provided with emergency electric operation first to facilitate emergency rescue. The rescue device uses manual or electric brake release. In the case of power failure, this rescue device can open and drive the main engine brake through a specified operation outside the hoistway. The rescue work mainly depends on the unbalanced torque of the car and the counterweight. Move to the nearest landing. However, this rescue method has a rescue blind zone, that is, when the weight of the car and the counterweight are equal, the unbalanced moment difference is small, and when the car rushes to the top or squats, the rescue cannot be carried out only by opening the brake. Judging from the on-site inspection, many manufacturers have not considered this issue, which makes rescue work impossible when the above-mentioned situation occurs. The operation method of some manufacturers to solve this problem is as follows: Rescue when the weight of the car and the counterweight is equal. At this time, the unbalanced torque difference is small. After the brake is released, the car and the counterweight will not move, and the weight difference cannot be used for rescue. To break this state of balance, it is necessary to increase the weight of the car or counterweight. For example, when using a hook code, first determine the position of the car during rescue. If the car needs to move up the leveling layer, the rescuer will enter the pit from the base station, hang the hook code at the lower part of the counterweight side compensation chain, and leave the pit. Release the brake. Since the counterweight is heavier than the car, the car moves up to the leveling position. The rescuer opens the landing door and the car door and releases people. If the car needs to move down the leveling layer, the rescuer will go up the car top, put the hook code on the car top, or enter the pit and hang the hook code on the car side compensation chain, leave the car top or pit, and release With the brake, the car moves down to the leveling position, and the door is opened to release people. Rescue when the car hits the roof. At this time, the weight of the car side is basically less than the weight of the counterweight. Enter the pit and hang the hook on the car side compensation chain. After the brake is released, the car can move down to the leveling position. Release people. Rescue when the car is squatting on the bottom. At this time, the weight of the car is often greater than the weight of the counterweight. The rescuer gets on the top of the car and hangs the hook on the counterweight side compensation chain. The personnel leave the car top. After the brake is released, the car is on Just move to the leveling position. The method of supporting the operation state of the car Since the emergency operation of the machine roomless elevator is carried out outside the hoistway, there is a problem that cannot be ignored, that is, how to grasp the direction of the car at any time during the rescue process and whether the car enters the leveling This information is the basic guarantee for the rapid and safe realization of emergency rescue. At present, the structure type of buzzer and observation hole is commonly used. Observation holes Some elevator manufacturers have made leveling marks on the overspeed governor rope and installed a lighting lamp at a proper position in the hoistway. The light shines directly on the overspeed governor rope. This light is powered by an emergency power supply when the elevator is out of power. The observation hole is installed near the emergency operation device, usually at an appropriate height on the back of the control cabinet, and only maintenance personnel can access it.
A better way is that the observation hole can be covered with plexiglass or iron sheet at ordinary times, and it can be easily removed during emergency rescue. The function of the observation hole is not only used for emergency rescue, but also can rely on this device to observe the elevator operation during the function test. Buzzer When the car reaches the leveling area, the buzzer will give a sound prompt to tell the rescuers that the car has arrived at the landing, but the rescuers can only tell the car that the car is stopped based on the sound of the buzzer. On which floor, through the observation hole and the floor mark on the speed limiter rope, you can immediately know the floor where the car is located, reducing rescue time, which is more important for high-rise elevators. From the above discussion, it can be seen that the emergency rescue device of the machine-roomless elevator should be used for emergency electric operation first. If a manual or electric brake release device is used, a hook code should be configured, there should be an observation hole near the brake release device, a floor mark should be placed on the speed limiter rope in the hoistway, and a buzzer indicating that the car has reached the landing Device. Only equipped with a more complete rescue device can ensure that rescue work is carried out quickly, accurately and safely
The unreasonable calculation results in uneven airflow distribution in the car, resulting in uneven indoor temperature and humidity; ③The introduction of outdoor fresh air is not ideal. At present, except for the elevator shaft of a few high-end buildings, the elevator shaft of most buildings is transported by cold air in summer. There is no mechanical ventilation system.
The ASHRAE standard defines thermal comfort as follows: a state of satisfaction with the thermal environment. For any air conditioning (heating, cooling) system, human thermal comfort is an important part of it. At present, the most commonly used and easiest to master comfort models are PMV (PredictedMeanVote, predicted average vote value) and PPD (PredictedPercentage of Dissatisfied, predicted percentage of dissatisfaction). PMV is a comprehensive index that comprehensively considers the effects of human activity, clothing thermal resistance, air temperature, average radiation temperature, air flow speed, and air humidity on thermal comfort. PMV in the Fanger comfort equation and the above 6 The relationship between these factors can be found in the literature <2>. In order to study thermal comfort, Fanger has done a lot of experiments. He asked the subjects to make subjective responses to the feelings of cold and heat (using the voting method) in a specific artificial environment under the combination of different factors that affect human comfort, that is, the seven-level feeling. But even if most people are satisfied with the thermal environment, there will still be people who are dissatisfied due to the physiological differences between people. To illustrate this relationship, the indicator PPD is proposed. It can be seen that even if a certain environmental condition is satisfactory to most people, such as PMV=0, 5% of people are still dissatisfied. The ISO7730 standard recommends that the PPD value for a certain thermal environment should be less than 10%, so the thermal comfort requirement of the indoor environment should be -0.5＜PMV＜0.5.
In order to obtain the thermal environment in the car, the following is an analysis of the most commonly used elevator of a certain brand with a load capacity of 1000kg and a specification of 13 people. The internal structure is that the length X is 1600mm, the width Z is 1500mm, the height Y is 2350mm, and the plane with Z=1500mm is the plane where the elevator door is located. Assume that there are 12 passengers in the elevator, 4 people in the horizontal direction, and 3 people in the vertical direction. The heat dissipation capacity per person is 35W, which is a total of 420W. There is a fluorescent lamp on the top of the car, and each heat dissipation capacity is 30W, totaling 180W. The 40mm double louvered air outlet delivers air, and uses the gap at the bottom of the car (size: 1500mm, 15mm, 2+1600mm, 15mm) to exhaust the air, the car wall is set to be insulated, the initial temperature in the car is 31%, and the ventilation temperature is 31% , The relative humidity is 83%, the ventilation rate is 0.08m3/s, the air supply speed is set to 5m/s; outdoor conditions are 31 benefits. The position of the air supply and exhaust outlets, the air circulation path and the ventilation volume of the car ventilation are called airflow organization. According to the elevator specifications, the longest time for the elevator to go from the first floor to the top floor should not exceed 48s. Because its running speed is small, the influence of the elevator running speed on the ventilation in the car is not considered. The non-steady state simulation is adopted, and the step length is set to 10s. Simulate for 48s, the elevator door does not open during operation, and investigate the air temperature, speed and thermal perception of people in the car.
The main reasons for the poor thermal comfort environment in the elevator car are: concentrated heat sources, huge quantities, uneven temperature and speed distribution, and insufficient ventilation. You can choose to increase the air volume to improve the thermal comfort. When the air volume is 0.32m3/s, the thermal environment in the car is at an acceptable value. The PMV value has been reduced from the original 2.65 to 2.05. Four fans of the same model as the original model can be used, and the air outlets are arranged symmetrically; the top air supply is changed to the top exhaust air, and an acceptable thermal environment can also be obtained, and the required air volume It is less than when the air supply is increased. The average indoor speed is also low. Using this kind of ventilation method not only can remove more heat, but also maintain negative pressure in the car. When the elevator doors on each floor are opened, more low-temperature air can flow in, which is more conducive to reducing the temperature in the car. . The air in the elevator shaft is used for the ventilation in the car to limit the cooling capacity of the air supply. According to ventilation regulations, when the calculated outdoor temperature of summer ventilation exceeds 30%, the temperature difference between the calculated ventilation temperature and the temperature of the working place cannot exceed 3%. The summer ventilation temperature in the south is generally very high. For example, the summer ventilation temperature in cities such as Guangzhou, Shanghai, Nanjing and Wuhan all exceeds 30 Yi. It is recommended to reduce the supply air temperature through the treatment of the air in the elevator shaft (ie: incorporate the elevator shaft into the ventilation and air-conditioning design of the entire building, and send cold air to the elevator shaft); and the outdoor fresh air can be appropriately added to the shaft, which will affect the elevator car. The air quality inside has a greater improvement.