The mechanical deflection angle of the movable part of the surface can be measured and converted, and the size to be measured is directly indicated by the indicator, so it is also called the direct-reading appearance.
According to the working principle, the indication surface can be divided into magnetoelectric appearance, electromagnetic system appearance, electric system appearance and induction system appearance.
The appearance of the magnetoelectric system is made according to the principle of the electromagnetized conductor being subjected to electromagnetic force in the magnetic field, which has the advantages of high accuracy, high sensitivity, uniform scale, low power consumption, and convenient reading, but its overload capacity is poor, and the structure is complex and the cost is high, and it can only measure the direct flow.
The appearance of the electromagnetic system is the same as that of the magnetoelectric system, which is made by the principle of electromagnetic interaction, but its magnetic field is generated by the measured current and can be used in AC and DC circuits.
An electric system exterior is a type of exterior that works through the interaction of the current in one or more dynamic coils and the current in the fixed coil.
The appearance of the electric system has the advantages of high accuracy, AC and DC, and can form a variety of lines to measure a variety of parameters, but there are also deficiencies such as being susceptible to the influence of external magnetic fields, large power consumption, poor overload capacity, and uneven scale of the scale.
The appearance of the induction system is a mechanical indicator meter in which the rotational torque is generated by the interaction between the alternating magnetic field and the induced current in the conductor of the movable part.
The appearance of the induction system is simple, the cost is low, the working range is wide, and the overload capacity is strong, but unfortunately the accuracy is low, and it is only suitable for the measurement of AC circuits.
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Briefly describe the knowledge of instrument valves
Valves are the most common equipment in chemical enterprises and play a great role. They seem to be simple and easy, but in the actual operation process, they also need to meet the relevant technical requirements, otherwise they will cause safety accidents. Only the valves related to our liquid level appearance are introduced here, and other equipment is not analyzed. ...
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Wuzhong instrument high pressure differential control valve selection
1. Confirm the working conditions: P1, △P, Q, T1, fluid characteristics, allowable noise, etc.; Select the appropriate ANSI pressure class for the body and trim requirements
2. Calculate the required initial Cv value, check the noise and cavitation levels
3. Select the type of trim of the control valve: if there is no noise ...
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Wuzhong instrument spherical core processing island
A few days ago, in a large digital workshop of Wuzhong Instrument Co., Ltd., the operators were working carefully. Every day, tens of thousands of parts orders are sent from dozens of sales outlets across the country such as Guangzhou and Hainan, and nearly 200 pieces of equipment in the workshop are processed and produced.
Because of the working conditions ...
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Prevention and elimination methods of leakage on the sealing surface of valves
1. When the sealing surface is grinding, the grinding tools, abrasives, abrasive cloth and sandpaper and other objects should be selected in a reasonable grinding method, and the coloring inspection should be carried out after grinding, and the sealing surface should be free of indentations, cracks, scratches and other shortcomings;
Second, the connection between the valve stem and the closure should meet the planning requirements, and the top center is not suitable.
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Wuzhong instrument control valve knowledge
The actuator of the control valve has pneumatic type, electric type and electro-hydraulic linkage type, and the pneumatic equipment is divided into barrier type and cylinder type. Depending on the action when the operating signal and the drive source disappear, the actuator has a forward type, a reverse type, a non-directional type, and a persistent type. The positive type is used in the operation signal and drive ...
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Advantages and disadvantages of Wuzhong instrument gate valve
Gate valves have the following advantages:
Low fluid resistance: the medium channel inside the valve body is straight, and the medium does not change its direction of activity when it flows through the gate valve.
The torque required for opening and closing is small;
It can be used on a ring network pipeline where the medium moves in both directions, that is, the flow direction of the medium is not ...
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How to use thermocouples in Wuzhong meters
The correct use of thermocouples can not only accurately obtain the temperature value and ensure that the product is qualified, but also save the data consumption of thermocouples, which can not only save money but also ensure product quality. Incorrect installations, errors such as thermal conductivity and time lag are the first errors in the use of thermocouples.
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The working principle of the automatic circulation valve - Wuzhong instrument
The active circulation valve is a pump protection device. It actively protects the centrifugal pump (especially the hot water medium) from partial cavitation damage and instability that may occur in the pump body when operating at low load. Once the pump flow rate falls below the preset flow, the bypass is completely opened to ensure that the pump needs a small flow rate. Namely...
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The structure of the pressure reducing valve - Wuzhong instrument
Load the organization
The role of the loading tissue is to apply a downward loading force from the top of the pressure reducing valve. The loading structure of the FITOK pressure reducing valve is mainly the loading of tension springs. Tension spring loading has the advantage of reliability and low cost, and is the most versatile loading device in pressure reducing valves.
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The control valve can also be called a "full-function valve" - Wuzhong instrument
There are a total of eight functions of the conditioning valve, and the eight functions of the full-function ultra-light conditioning valve are excellent, so it is called "full-function valve".
1. The conditioning function is one of the main functions of the conditioning valve, which is manifested as (1) flow characteristics; (2) Adjustable ratio R; ...
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Wuzhong instrument pneumatic valve fault location analysis
1. In the case of interlocking action of pneumatic valve equipment, the valve orientation should have the following situations:
The EC air supply is discarded and the valve is in a closed position
FO__ air source is discarded, and the valve is in the opening position
FL-_ The air source is lost, and the valve is in the time position and has been insisting
FL ...
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Analysis of technical problems of Wuzhong instrument chemical centrifugal pump
1. What is a chemical centrifugal pump?
Answer: It is a machine that adds liquid energy by increasing the effect of centrifugal force through the impeller to increase the mechanical energy of the liquid, so as to transport the liquid.
2. What are the characteristics of chemical centrifugal pumps?
Answer...
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Wuzhong instrument gate valve movement mode
When the gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, only rely on the medium pressure to press the sealing surface of the ram to the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves are forcibly sealed, that is, when the valve is closed, it is necessary to rely on external force to forcibly ...
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Pneumatic valve fault location analysis - Wuzhong instrument
In the process of use, several problems are usually presented in the direction of (FO, FC, FL), and the "fault" in the valve fault closing/obstacle opening refers to: the action of the valve when the gas source is gone. For the fault location of pneumatic valves, it is mainly divided into several situations:
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Valve positioner classification - Wuzhong instrument
1. The valve positioner is divided into pneumatic valve positioner, electrical valve positioner and intelligent valve positioner according to the input signal.
(1) The input signal of the pneumatic valve positioner is a standardized gas signal, for example, the 20-100kPa gas signal, and its output signal is also a standardized gas signal. ( ...
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Various valve types and principles - Wuzhong instrument
The valve is a control component in the fluid transportation system, which has the functions of shut-off, conditioning, diversion, preventing backflow, stabilizing pressure, diverting or overflowing pressure relief.
Valves for fluid control systems, from the simplest shut-off valves to the most chaotic valves used in automated control systems, range from ...
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Wuzhong instrument valve selection precautions
Valve application requirements
(1) General gate valves, ball valves, and globe valves are prohibited from dispatching according to their structural characteristics. However, in process design, it is widely used for mediation. Because of the scheduling application, the valve seal has been in a throttling state for a long time, and the impurities in the oil have washed the seal, endangering the seal.
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Identify the valve refurbishment method - Wuzhong instrument
1. Remove the nut and identification plate at the upper end of the valve stem, and look at the lock nut raw material inside, the raw material is brass, otherwise it is a counterfeit product.
2. Look at the steel seal, the valve steel seal is pressed on it before the valve has passed the heat treatment, and the professional steel seal skills are used.
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Standard pressure method for turbine fixed ball valve - Wuzhong instrument
The process of shell experiments and seal experiments done by turbine fixed ball valves in some artificial environments is as follows.
1. The double blocking and discharge function of the turbine fixed ball valve: the turbine ball valve is fixed by using the tension spring preload floating valve seat, when the valve is in two different states of full open and fully closed, the flow ...
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Sealing performance requirements for cryogenic disc valves - Wuzhong instrument
There are two main reasons for the leakage of cryogenic valves, one is internal leakage; The second is leakage.
1) Internal leakage of the valve
The main reason is the deformation of the sealing pair at low temperature.
When the temperature of the medium drops to the point where the data undergoes a phase change, the volume changes ...
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