In the daily maintenance work of the clean room, the function of instruments is equivalent to a mirror to supervise the running state of the clean room. From the point of view of clean room, this paper talks about the application of measuring instruments in clean room.
A List of Main Instruments and Instruments
1. Air pressure measuring instrument: It is mainly used to measure the micro-pressure difference between clean rooms and between clean and non-clean areas. It can also measure wind speed and calculate air volume by pressure difference method.
(1) Liquid manometer: The liquid manometer has the advantages of easy use, low price, high accuracy, easy manufacture and installation, but it has the shortcomings of limited measuring range and fragile glass tube.
Commonly used working fluids are alcohol, water, mercury and so on. Alcohol and water are the main measuring fluids in clean room.
The main types of liquid manometers are U-tube manometer, inclined tube manometer and compensatory manometer.
(2) Spring manometer: The spring manometer is based on the principle that the spring element deforms under the action of the measured pressure, and its deformation is a function of the measured pressure. Its advantages are simple structure, easy to carry, convenient installation and low cost. Commonly used spring manometers are: spring tube manometer, diaphragm tube manometer and diaphragm core manometer.
(3) Electrical manometer: Electrical manometer is a manometer which uses piezoelectric principle or electrical method such as resistance change under high voltage to measure pressure. It is suitable for measuring pressure when the change is very fast, the value is very high or almost absolute vacuum.
2. Wind speed and wind measurement instruments:
(1) The principle of wind speed measuring instrument includes mechanical type, heat dissipation type and dynamic pressure measuring type.
A. Mechanical anemometer: such as airfoil anemometer, which uses the original pressure of flowing gas to drive the mechanical device to display its flow velocity.
B. Heat dissipation anemometer: It is based on the heat dissipation of the heated object in the fluid is proportional to the flow velocity of the fluid. It can measure the heat dissipation of the sensor, that is, the flow velocity of the fluid. The commonly used heat dissipation anemometers are hot wire anemometer and hot ball anemometer.
(2) Air Meter: In the clean room, the total air volume is usually measured by air duct method, and the return air volume of each room is mostly measured by air outlet method. Its principle is that the average air speed is multiplied by the cross-section area.
3. Cleanliness tester:
A. Dust particle detection instrument: At present, the cleanliness detection of clean room mainly uses light scattering dust particle counter, which is divided into incandescent lamp dust particle counter and laser dust particle counter.
Its principle is to use the scattering phenomenon of particles in the air to measure the number of particles by converting the light pulse signal of particles in the sampled air to the corresponding electric pulse signal, and to measure the size of particles by using the relationship between the light scattering intensity of particles and the square of particle size.
B. Instruments for the detection of biological particles: At present, the main methods for the detection of biological particles are medium method and filter method. The instruments used are planktonic bacteria sampler and sedimentation bacteria sampler.
The main types of plankton samplers are solid impact sampler, centrifugal air microorganism sampler, cyclone microorganism sampler, liquid impact microorganism sampler, filter microorganism sampler and large capacity electrostatic precipitation sampler.
Sedimentary bacteria sampler mainly includes high-pressure disinfection pot, incubator and Petri dish.
4. Temperature tester: general thermometer, according to its principle of action can be divided into expansion thermometer, pressure thermometer, thermocouple thermometer and resistance thermometer.
Expansion thermometers: solid Expansion thermometers and liquid expansion thermometers.
B. Pressure thermometer: It can be divided into gas-filled pressure thermometer and steam-filled pressure thermometer.
C. Thermocouple thermometer: It is based on the principle of thermoelectric effect. When the temperature of two different metal nodes is different, there will be electromotive force. If the temperature of one point is known, the temperature of another point can be calculated by measuring the electromotive force.
D. Resistance thermometer: Based on the fact that the resistance of a metal and its alloys or semiconductors varies with temperature, the temperature can be measured by measuring the resistance accurately. The advantages of resistance thermometer are: high accuracy, sensitivity, fast response, wide temperature measurement range, no need for cold node compensation, and can be used for remote temperature measurement.
5. Humidity tester: According to its principle, humidity tester can be divided into dry-wet bulb thermometer, hair thermometer, electric thermometer and so on.
6. Noise tester: The principle of noise tester is to convert sound energy into electricity by capacitive microphone, and then to be processed by amplifier and geophone. Finally, the sound pressure value is given.
7. Illuminance tester: The principle of portable illuminometer is to use a photosensitive element as a probe. When there is light, the photocurrent will be generated. The stronger the light, the greater the photocurrent, the illuminance can be measured when measuring the current.
The professional technicians of Ed Purification Engineering design a reasonable plan to adapt to the production process and the cost of the project. The design technical indicators meet the national standard of clean room. The experienced construction team of the purification project is fast and efficient, and the after-sales service is perfect. To learn more about the medical purification industry, please pay attention to the Wechat Public No. Aide-188 (Ed Purification and Oxygen Supply)