TWI842339B - Axial-flow water meter and impeller thereof - Google Patents

Abstract

The present invention relates to an axial-flow water meter and an impeller thereof. The impeller includes an axle member and a blade member. The blade member includes a central portion and a blade portion, wherein the central portion surrounds the axle member, and the blade portion surrounds the central portion. The central portion is made of a first material, and the blade portion is made of a second material, wherein the density of the first material is greater than 1g/cm³, and the density of the second material is less than 1g/cm³. Moreover, when the blade member surrounds the axle member, the density of the impeller is between 0.95g/cm³ and 1.20g/cm³. The impeller is semi-submersible when being placed into water, and thereby improves the sensing sensitivity for water-volume detection. According to the present invention, when being used to detect high-flow water, the impeller can withstand the impact of high-flow water; when being used to detect low-flow water, the impeller can be pushed to rotate easily.

Description

Axial flow water meter and its impeller

The present invention relates to an axial flow water meter and its impeller, and in particular to an invention in which the central portion of the impeller has a material with a higher tensile strength and the blade portion of the impeller has a material with a lower tensile strength and a lower density through secondary injection molding.

A water meter is used to measure the volume of water flowing through the water meter. Among them, the axial flow water meter immerses the impeller in the water flow, and the extension direction of the impeller's rotating axis is parallel to the direction of the water flow. The volume of water flowing through the water meter is calculated by the number of revolutions of the impeller. In order to consider the strength of the impeller during use, the impeller is usually made of metal or materials with high mechanical strength to withstand the impact of high-pressure water flow. However, please refer to Figure 6. Although the heavy impeller A made of a single material of metal or engineering plastic with high mechanical strength (density greater than 1g/ ^cm3 ) can improve strength, the weight F1 of the heavy impeller A also increases with the material of manufacture. The heavy impeller A will cause a greater load on the rotating shaft, such as increased friction. When the water flow through the water meter is low, the low-flow water cannot easily push the heavy impeller A, making it impossible for the water meter to detect the low flow. In addition, the increased friction will also cause problems such as uneven rotation or increased wear.

Please refer to Figure 7. To solve the problem of being unable to detect low-flow water flow and improve the sensitivity of the impeller, the mass of the impeller itself is often reduced to reduce the friction between the shaft and the shaft contact surface. Therefore, a single plastic material with a material density less than water is often selected to make a light impeller B, so that the light impeller B is lighter and easier to be pushed by low-flow water, so that the water meter can detect low-flow water. However, when the light impeller B is immersed in water, buoyancy F2 will be generated, and the light impeller B will apply an upward buoyancy F2 to the rotating shaft, thereby increasing the friction between the shaft and the shaft contact surface. Similarly, it will also cause problems such as uneven rotation or increased wear. Moreover, the material density is less than 1g/cm The mechanical strength of the plastic material of ³ is also insufficient. When the water flow is too large, the impeller B itself will not be able to withstand the large water flow and will be deformed, and even the plastic material of the impeller B and the shaft will not be able to be combined and separated, causing the impeller B to be damaged and unusable.

Therefore, in order to improve the sensitivity of the impeller to detect low flow rate water flow, and when the flow rate is large, the impeller also has better mechanical strength to resist the impact of large water flow, and an impeller is proposed, comprising: a shaft; a blade member, including a center portion and a blade portion, the center portion is covered on the shaft, the center portion is provided with a plurality of protrusions from the surface, the blade portion covers the center portion, the protrusions extend into the blade portion, and the center portion is covered between two opposite sides of the blade portion, and the two opposite ends of the shaft extend from the two opposite sides of the blade portion respectively, the center portion is made of a first material, and the blade portion is made of a second material, the density of the first material is greater than 1g/ ^cm3 , and the density of the second material is less than 1g/ ^cm3 , and when the blade member is wrapped around the shaft, the density of the impeller is between 0.95g/cm ³ and 1.20g/cm ³ .

Furthermore, the first material and the second material are both polymer materials.

Furthermore, the tensile strength of the first material is between 880 and 920 kg/cm ² , and the tensile strength of the second material is between 360 and 400 kg/cm ² .

Furthermore, the impact strength of the first material is between 50 and 55 J/m, and the impact strength of the second material is between 2.5 and 3.5 J/m.

Furthermore, the first material is polyphenylene oxide (PPO).

Furthermore, the second material is polypropylene (PP).

Furthermore, the material of the shaft is tungsten steel.

Furthermore, the shaft has two opposite ends and a middle section between the two opposite ends, the middle section is concavely provided with a plurality of embedding grooves, and the central portion is wrapped around the middle section of the shaft and embedded in the aforementioned embedding grooves.

Furthermore, the central portion is covered on the shaft by plastic injection molding, and the blade portion is covered on the central portion by plastic injection molding.

An axial flow water meter includes an impeller as described above, and the axial flow water meter includes a water meter body; the impeller is arranged on the water meter body.

Based on the above technical features, the following effects can be achieved:

1. The center of the blade is made of a material with high density and high tensile strength. When the impeller is pushed by water, the center of the blade has a higher bearing capacity. When the water flow is large, the center will not deform due to insufficient bearing capacity, causing the blade to separate from the shaft and damage the impeller.

2. The blade part of the blade is made of a material with a lower density and lower tensile strength, so that the density of the impeller as a whole is close to the density of water and presents a semi-floating state, thereby reducing the weight of the impeller sinking. When low water flows through the impeller, the blade can be pushed by the low water and rotate easily, so that the water meter can detect the volume of low water flowing through.

3. Because the density of the impeller is close to that of water, when the impeller is immersed in water, it is in a semi-floating state. The impeller will not float completely upwards due to being too light, causing the axis to bear the upward buoyancy, nor will it be too heavy to sink completely, causing the axis to bear the downward gravity. This can reduce the friction when the axis rotates, making the impeller more sensitive when sensing water flow.

1: Water meter body

2: Impeller

21: Shafts

22: Leaf pieces

221: Center

222: Leaf section

F1: Weight

F2: Buoyancy

A:Heavy impeller

B: Light impeller

[Figure 1] is a three-dimensional appearance diagram of the impeller of the present invention.

[Figure 2] is a cross-sectional view of the impeller of the present invention.

[Figure 3] is a cross-sectional view of the axial flow water meter of the present invention.

[Figure 4] is a schematic diagram of the operation of the axial flow water meter of the present invention.

[Figure 5] is a schematic diagram of the operation of the axial flow water meter of the present invention.

[Figure 6] is a diagram showing that the axial flow water meter is equipped with a heavier impeller and cannot sense small amounts of water.

[Figure 7] is a diagram showing an axial flow water meter equipped with a lighter impeller and the buoyancy generated by the impeller in water.

Combining the above technical features, the main functions of the axial flow water meter and its impeller of the present invention can be clearly presented in the following embodiments.

Please refer to the first, second and third figures first. The axial flow water meter of the present invention includes a water meter body 1 and an impeller 2. The impeller 2 is arranged on the water meter body 1.

The impeller 2 includes a shaft 21 and a blade 22. The blade 22 includes a center portion 221 and a blade portion 222. The center portion 221 is coated on the shaft 21. The blade portion 222 covers the center portion 221. The center portion 221 is made of a first material. The blade portion 222 is made of a second material. The density of the first material is greater than 1g/ ^cm3 . The density of the second material is less than 1g/ ^cm3 . When the blade 22 is coated on the shaft 21, the density of the impeller 2 is between 0.95g/ ^cm3 and 1.20g/cm3. ³ ; specifically, the material of the shaft 21 is tungsten steel, and the shaft 21 has two opposite ends and a middle section located between the two opposite ends, the middle section is concavely provided with two embedding grooves, the center portion 221 is covered on the middle section of the shaft 21 and embedded in the aforementioned embedding grooves, the center portion 221 is convexly provided with a plurality of protrusions from the surface, the blade portion 222 covers the aforementioned protrusions, and the center portion 221 is covered between the two opposite sides of the blade portion 222, and the two opposite ends of the shaft 21 extend from the two opposite sides of the blade portion 222. The central portion 221 is coated on the shaft 21 by injection molding, and the blade portion 222 is coated on the central portion 221 and the middle portion of the shaft 21 by injection molding. The first material and the second material are both polymer materials. The first material is polyphenylene oxide (PPO), and the tensile strength of the first material is between 880 and 920 kg/cm ² and the impact strength is between 50 and 55 J/m. The second material is polypropylene (PP), and the tensile strength of the second material is between 360 and 400 kg/cm ² and the impact strength is between 2.5 and 3.5 J/m.

Please refer to the second and fourth figures. When the axial flow water meter of the present invention is used, when the water flow rate is high and the water pressure is strong, the water pressure during the flow will drive the impeller 2 to rotate, and the sensing element in the water meter body 1 will sense and calculate the number of times the impeller 2 rotates, and then convert it into the volume of water flowing through the water meter body 1, thereby recording the water volume. When the impeller 2 is driven by the water flow and rotates, the blade portion 222 of the blade member 22 is subjected to a smaller force near the blade tip, while the central portion 221 of the blade member 22 is subjected to a larger force. When the water flow is larger, the force on the central portion 221 of the blade member 22 will also increase. The central portion 221 of the blade member 22 of the present invention is made of a material with a higher density and a higher tensile strength, which can withstand larger water flow. The flow rate is controlled so that the center portion 221 of the blade 22 will not be deformed due to insufficient tensile strength when subjected to a large water flow rate. The deformed center portion 221 will affect the coupling force between the blade 22 and the shaft 21. After long-term use, the blade 22 will separate from the shaft 21 and the impeller 2 will be damaged, making the axial flow water meter of the present invention unable to continue to detect the amount of water flowing through.

Please refer to the second and fifth figures. Since the overall density of the impeller 2 of the present invention is close to the density of water, when the impeller 2 is immersed in the water flow, the impeller 2 will be in a semi-floating state, and the blade portion 222 of the blade member 22 is made of a material with a lower density, so that the weight of the blade member 22 is lighter. When the water flow rate is low and the water pressure is weak, the low-flow water flow can still easily push the impeller 2 to rotate, so that the water meter body 1 detects the low-flow water flow and records the water volume.

By setting the density of the impeller 2 as a whole close to the density of water, the impeller 2 can have a semi-floating effect when immersed in water, which can improve the sensitivity of sensing the amount of water, and the central part 221 of the blade member 22 is made of a material with a higher density and a higher tensile strength, and the blade part 222 of the blade member 22 is made of a material with a lower density and a lower tensile strength, which can simultaneously meet the requirements of the water flow. When the water flow is large, the center portion 221 of the blade member 22 must have a higher bearing capacity. When the water flow is low, the blade portion 222 of the blade member 22 is light and can still be pushed and rotated easily by the low water flow, so that the axial flow water meter of the present invention can withstand the water pressure of high flow when detecting high flow, and the impeller 2 can still be easily pushed and rotated when detecting low flow.

Combined with the description of the above embodiments, the operation, use and effects of the present invention can be fully understood. However, the above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of implementation of the present invention. In other words, simple equivalent changes and modifications made according to the scope of the patent application and the content of the invention description are all within the scope of the present invention.

2: Impeller

21: Shafts

22: Leaf pieces

221: Center

222: Leaf section

Claims (8)

An impeller comprises: a shaft having two opposite ends and a middle section between the two opposite ends, the middle section being concavely provided with a plurality of embedded grooves; a blade member comprising a central portion and a blade portion, the central portion being covered by plastic injection molding on the middle section of the shaft and embedded in the aforementioned embedded grooves, the central portion being provided with a plurality of protrusions on the surface, the blade portion being covered by plastic injection molding on the central portion and the shaft at the same time, so that the aforementioned protrusions extend into the blade portion, and the central portion is covered between two opposite sides of the blade portion, and the two opposite ends of the shaft respectively extend from the two opposite sides of the blade portion, the central portion is made of a first material, and the blade portion is made of a second material, the density of the first material is greater than 1g/ ^cm3 , and the density of the second material is less than 1g/ ^cm3 , and when the blade member is wrapped around the shaft, the density of the impeller is between 0.95g/cm ³ and 1.20g/cm ³ . The impeller as described in claim 1, wherein the first material and the second material are both polymer materials. The impeller as claimed in claim 2, wherein the tensile strength of the first material is between 880 and 920 kg/cm ² , and the tensile strength of the second material is between 360 and 400 kg/cm ² . The impeller as described in claim 2, wherein the impact strength of the first material is between 50 and 55 J/m, and the impact strength of the second material is between 2.5 and 3.5 J/m. The impeller as described in claim 2, wherein the first material is polyphenylene oxide (PPO). The impeller as described in claim 2, wherein the second material is polypropylene (PP). An impeller as described in claim 1, wherein the material of the shaft is tungsten steel. An axial flow water meter, comprising an impeller as in any one of claims 1 to 7, the axial flow water meter comprising: a water meter body; the impeller is arranged on the water meter body.

Images