Its
advantage is that there is no
friction force caused by magnetic
coupling force, but its disadvantages are: 1. The structure of the loop supplying power to the spotlight is complicated
2. The electric guide rail is immersed in the liquid. It must be made of
corrosion-resistant materials, and it cannot be used in explosion-proof occasions. When running up and down, the
brush will carry the medium from the guide rail to the float.
3. There is an aging problem in the elastic insulating ring, which affects reliable use
5. The power supply to the spotlight and the power supply to the photosensitive element belong to two circuits, and the float measurement and photosensitive element parts are independent, that is, the magnetic float uses pulleys and tracks, and the remote sensor uses a set of fixed brackets, resulting in a complex structure
6. Roller pulleys and spotlights are placed on the float, which further increases the quality of the float, and then needs to increase the volume and thickness of the float and the
float chamber shell. In this case, it is not suitable for low-density and high-pressure applications.
7. It is easy to form water film on the surface of the spotlight or gather dust on the photosensitive element, which will affect the use
10. There are many internal parts in the
float chamber shell. When it is used in strong corrosive media, all the internal parts must be made of expensive
corrosion-resistant materials, resulting in increased costs.
[0008] As described in ZL99220056.3, ZL94235895.3, ZL200820107045.9, ZL94206404.6, and ZL89210466.X, they have the following problems respectively: 1. The structure is complex and huge, the transmission mechanism has many wire wheels, and the friction is large, which affects the accuracy and sensitivity
3. Some have no remote transmission or the remote transmission
signal is not continuous
4. Cumulative errors caused by slipping
5. On-site instruction and remote transmission use two independent mechanisms, resulting in complex structure and high cost
[0009] As described in ZL200410015416.7, this liquid level gauge can solve the application of high-pressure boilers well, but it has the following disadvantages: 1. Two structural parts or fixed frames are used for on-site indication and remote transmission, making the structure complicated
2. The remote transmission
signal is not continuous
3. The magnetic car needs 4 wheels, otherwise the cursor will deflect or
shake up and down and cannot be used. This will make the structure complicated, and the second will increase the weight of the magnetic car, thereby increasing the load of the float, which is equivalent to the increase in the weight of the float. , it is difficult to meet the use in high temperature and
high pressure or
high pressure and
low density medium occasions
[0010] As mentioned in ZL89210640.9, the liquid level gauge uses rolling friction to reduce the frictional force. Its disadvantages are: 1. The signal remote transmission part needs to add a sliding wire
resistor with a skeleton and the sliding wire
resistor. The movable arm makes the structure complex and additionally increases the friction
2. The local instructions are not clear
3. Although it is mentioned that the float is simple in spherical shape, when the float is made of non-ferromagnetic material, ferromagnetic material is inlaid on the
waterline or equatorial zone, which will form sliding friction and cause large
friction force. It can be seen that the inventor only considered The spherical float is simple to manufacture, and the ferromagnetic material is embedded in the horizontal line or equatorial zone, it can be seen that the inventor did not consider the influence of the shape of the float on the friction force
But there are the following shortcomings: 1. The float is open, and the condensate is easy to deposit inside the float, which affects normal use
2. The structure is complicated, and a lot of parts are used only for the clear display on site
3. At the same time, there are some problems listed in the aforementioned ZL200410015416.7
In addition, the
reed switch signal is discontinuous, unreliable, and the circuit is complicated
[0013] As described in ZL97243163.2, its
advantage is that the on-site instructions are clear, but there are still the following shortcomings: 1. Two pairs of static contacts are used to connect different light-emitting diodes, so that there are many switches and light-emitting elements, which affects reliability.
2. More components and more complex structure
3. The signal is not continuous
[0016] As described in ZL98239064.5, ZL01250601.X and ZL94239095.4, their advantages are that the load on the float is reduced and the sensitivity of the float is improved, but there are the following disadvantages: 1. The upper and lower pulleys are tensioned and displayed Belt, increased friction, causing
display lag and affecting accuracy
2. As a live display, the structure appears complex
3. If remote transmission is added, an additional mechanism consisting of a magnetic car is required, which makes the structure more complicated and brings great inconvenience to manufacturing and debugging.
5. The structure of the remote sensor is complex and the circuit is complicated
6. The remote transmission signal is discontinuous
7. There is sliding friction between the float and the float chamber, the friction force is large, and the display lags behind
[0017] As described in ZL97213710.6, it adopts a magnetic coupling structure, and adds a counterweight to the
color band outside the float to balance the quality of the float, which is conducive to improving its
operating temperature and
pressure range, and making it suitable for use in low-density occasions , but its shortcomings are: 1. When the
working pressure is high, the partition between the magnetic coupling parts will be very thick, and the axial end face of the partition is flat, which is equivalent to the
flange or blind plate on the pipeline , its thickness is determined by the
working pressure, temperature,
diameter, and the selected material, and the standard design will be very thick. If the thickness of the partition is too large, the magnetic coupling force will be too small until it does not work. The attenuation of the magnetic attraction force and the distance It is at the geometric level. If it is coupled radially outside the circular
pipe, its wall thickness will be much smaller. The wall thickness will be calculated by the design of pressure vessels or pipes. It can also be calculated by checking the
pressure vessel or
pipe design manual.
2. There are many parts in the floater, and
corrosion-resistant materials must be used for corrosive media, which increases the manufacturing cost
3. Steel wire and
steel belt are used inside, medium fluctuations can easily cause breakage and affect service life
4. Difficulty in visual inspection at night or in dark places
5. Two sets of structures are used for on-site indication and remote transmission, and the structure is complex, affecting reliability and high manufacturing cost
6. The upper and lower pulleys tighten the ribbon, which increases the friction and affects the sensitivity and measurement accuracy
7. The magnetic coupling is a sliding friction, the friction is large, and it also affects the accuracy
[0018] 3. Existing float type liquid level gauge without local indication but with remote transmission
[0019] As described in ZL99203851.0 and ZL02215560.0, their advantages are simple in structure, and their disadvantages are: 1. The sensing element is inserted into the tube extending in the container liquid, which is not resistant to high temperature
2. The float with a guide hole in the middle is not resistant to
high pressure3. Another set of connecting pipes is required if the local indication is realized
4. The float is easy to get stuck
5. Use
reed switch to make more components, unreliable and discontinuous signal
6. Two spiral tube type resistance wires are adjacently wound on the insulator, too dense is easy to
short circuit, too sparse will affect the accuracy
When the winding is too loose, it may not work properly due to the
point contact of the ball and the disconnection
7. It is possible to stop work during maintenance
[0020] As mentioned in ZL98229246.5: Its
advantage is that it does not require magnetic sensitive components, which greatly improves reliability, but it also has the following disadvantages: 1. The
resistor is placed in the sensor tube, which cannot be used in high temperature applications
3. The weight of the float increased by the magnetic trolley is not conducive to the use in high temperature and high pressure or high pressure and
low density occasions
4. The signal is not continuous
5. There is no on-site instruction, if additional on-site instructions are added, an additional set of institutions is required
6. The structure of the magnetic trolley is complex
[0024] 1. The remote transmission signal is not continuous;
[0025] 2. There are many precious metals or corrosion-resistant materials (pulleys, bearings, float chambers, etc. need to be selected according to
process conditions, such as high temperature and corrosion), which further increases the manufacturing cost;
[0027] 4. The counterweight (or counterweight) is immersed in the liquid to affect the accuracy;
[0028] 5. The local instructions are not clear; it is difficult to observe in dark places;
[0029] 6. Difficulty in
assembly and calibration;
[0035] 10. The structure is complex, such as on-site indication and remote transmission need two sets of mechanisms, other complex mechanical mechanisms, etc., with
large size, poor reliability and high cost
[0036] 11. The float or float chamber needs to be made very long, which wastes materials, is huge in size, and has a heavy burden on packaging and transportation
[0037] 12. The float is easy to get stuck
[0038] In addition, it is impossible to set up a large lighting lamp for a liquid level gauge in many factories and construction sites or in many outdoor places, and it is even more impossible to install lighting lamps for each liquid level gauge separately, which is not conducive to energy saving.
This leads to the inconvenience of observation
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