JPH0518690Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Field of Application> This invention relates to an electrode device for controlling moisture content in a container rotary concrete mixer.

<Conventional Technology> Concrete mixers for mixing cement and aggregate include fixed container types and rotating container types. When controlling the moisture content of concrete materials in the case of a rotating container type, if the container is fixed, it is easy to attach and wire the electrodes for measuring electrical resistance to the stationary mixer container, but in the case of a rotating container type, Even if electrodes are attached to the mixer container, it is difficult to extract signals from the electrodes. Therefore, it is common practice to measure the aggregate moisture content in advance by sampling.
Measures have been taken such as determining the amount of water to be added per batch and subsequently metering the amount of water to be added, or controlling the amount of water by controlling the current value of the stirring blade motor.

<Problems to be solved by the invention> When adjusting the moisture content based on the aggregate moisture content measured by sampling as described above, it is difficult to maintain a stable water/cement ratio because the variation in the aggregate moisture content from batch to batch is relatively large. In addition, when controlling the moisture content using the current value of the stirring blade motor, the motor current value required for stirring does not always fluctuate, so only rough control is possible.
None of them were completely satisfactory. This invention attempts to solve these conventional problems.

<Means for solving the problem> This invention consists of a mixer container that rotates in a fixed direction, a stirring blade that rotates in opposite directions between the center of rotation of the mixer container and the inner wall surface of the container, and a baffle plate. It has an electrode mounting member consisting of a cylindrical casing, and one end of the baffle plate is placed close to the inner wall surface of the part of the mixer container where the concrete material stirred by the stirring blade flows into a rotating flow along the mixer container. The surface of the baffle plate is fixed to a pedestal provided above the mixer container so as to face the rotating flow, and the electrode is attached to the electrode mounting member so that its surface is substantially flush with the surface of the baffle plate, By leading the lead wire electrically connected to the electrode to the outside through the cylindrical housing,
This solves most of the problems mentioned above.

<Example> In the container-rotating type concrete mixer shown in FIG.
is normally closed by an opening/closing lid (not shown). Concrete material is introduced into the mixer container 1 from the open upper end, and after being poured to a height indicated by the symbol L, it is kneaded by adding a predetermined amount of water and rotating the stirring blades 3. Stirring blade 3
As shown in FIG. 2, is arranged at an eccentric position inside the mixer container 1 with respect to the mixer container 1, and rotates in the opposite direction (arrow B) to the rotation direction (arrow A) of the mixer container 1. let 4 is a stirring blade drive motor, and 5 is its belt transmission means. The concrete material that has been mixed is discharged from the discharge hole 2 without leaving any residue by opening the cover of the discharge hole 2 and lowering the discharge guide 6 located at the position indicated by the two-dot chain line to the position indicated by the solid line. . 7 is the ejection guide 6
The elevating device 8 is a pedestal to which the elevating device 7 is attached, and is provided above the mixer container 1.

By the way, an electrode mounting member 10 is fixed to this pedestal 8, and an electrode 9 is attached to the electrode mounting member 10. It can be seen from FIG. 1 that the electrode 9 is located below the line L, so that it is embedded in the concrete material. Also, the second
The figure shows the mounting position of the electrode 9 when viewed from a plan view. That is, although FIG. 2 also shows the streamlines of the concrete material being mixed in the mixer container 1, since the mixer container 1 and the stirring blades 3 rotate in opposite directions as described above,
The flow of concrete material flowing approximately in the middle of the mixer container 1 fluctuates repeatedly and is not constant, so even if the electrode 9 is placed at such a location, the output will fluctuate greatly, so what is a suitable electrode installation location? I can't say that. On the other hand, the flow of concrete material flowing around the inner wall surface of the mixer container 1 is quite stable, partly due to the influence of centrifugal force! Moreover, the electrode mounting member 10 is composed of a baffle plate 10a and a cylindrical casing 10b, one end of which baffle plate 10a is brought close to the inner wall surface of the mixer container 1, and the surface of the baffle plate 10a is connected to the rotating mixer container. Mount 8 so as to face the flow of concrete material in 1.
If the electrode 9 is fixed to Impeccable.

As shown in FIG. 3, the electrode 9 has a central metal pole part 9a and an outer ceramic insulator part 9.
b, and the outermost metal protective outer skin part 9c, electrode mounting holes 11 are bored in the baffle plate 10a and the cylindrical casing 10b, and the protective cover protrudes into the inside of the cylindrical casing 10b. Attach the outer skin part 9c to the washer 12 and nut 1
3, and a lead wire 14 is fixed to the pole portion 9a, and the lead wire 14 is led out through the cylindrical housing 10b. On the other pole, another lead wire 16 is attached using the deflection plate 10a and the mounting bolt/nut 15 of the cylindrical housing 10b, and the lead wire 16 is pulled out to the outside in the same manner as described above. When the electrode 9 is attached, the surface of the electrode 9 and the surface of the baffle plate 10a are substantially flush with each other. This is to avoid disturbing the above-mentioned preferred flow conditions.

Next, the actual moisture control using the electrode 9 described above will be explained with reference to FIG. When the mixer container 1 is empty, the two electrodes are electrically disconnected, but when concrete material is poured into the mixer container 1 and the electrode 9 is buried in the concrete material, moisture is removed. The two poles become electrically conductive through the concrete material containing the . However, the electrical resistance between the two electrodes is high at the initial stage when water is not yet supplied. In FIG. 4, the resistance symbol means the electrical resistance of the concrete material. The electrical resistance of the concrete material detected by the electrode 9 is converted into a voltage signal by a resistance/voltage converter 17, and the voltage signal is sent to a controller 18.
The solenoid valve 1 of the water supply line is activated by the command from the controller 18.
9 is opened and water is supplied into the mixer container 1. As water is supplied in this manner and mixing progresses, the electrical resistance value of the concrete material decreases, but the solenoid valve 19 continues to be open. However, when the electrical resistance value decreases to the target water-to-cement ratio, the solenoid valve 19 is closed by the action of the controller 18, and the water supply is stopped.

To specifically determine the setting value for the controller 18, add water little by little manually for the first batch, stop when the appropriate amount of water is reached, and check the input value for the controller 18 at that time. It is sufficient to read the value on the meter and use the read value as the setting value of the controller 18. By the way, if you show it in concrete numbers,
Mixer container 1 diameter: 900 mm, depth: 600 mm, container rotation speed: 34 RPM, stirring blade rotation speed: 109 RPM, aggregate: 110
kg, cement 35 kg, water 11 kg (water/cement ratio)
0.31), the electrical resistance value is 190Ω.

<Effect of the invention> This invention has the following effects on the mixer container 1 that rotates in a fixed direction.
Since the stirring blades 3 rotate in opposite directions between the center of rotation of the mixer container 1 and the inner wall surface of the container, the concrete materials can be mixed well and sufficiently uniformly without moisture spots.

One end of the baffle plate 10a is placed close to the inner wall surface of the mixer container where the concrete material stirred by the stirring blades 3 flows in a rotating flow along the mixer container 1, so that the flow of concrete material is prevented at the part where the baffle plate 10a is located. The density of the water increases, the flow speed increases, and the flow becomes stable.
A stable moisture detection field will be formed.

Since the concrete material rubs the surface of the deflection plate 10a at high speed, the concrete material does not adhere to the surface of the electrode 9 attached flush with the surface of the deflection plate 10a, and cleaning to remove the adhesion is not required.

In addition, even if the container is a rotating type, since the electrode mounting member 10 is fixed to the pedestal 8 provided above the rotating mixer container 1, wiring with the electrode 9 is easy, and moisture can be adjusted by electrical resistance. . In addition, since the electrode 9 is installed flush with the baffle plate 10a with one end close to the inner surface of the mixer container 1, stable contact with the circulating concrete material is maintained, and no fluctuations in measured values are observed. This allows it to be mixed as a concrete material with a constant water/cement ratio.
Furthermore, a cylindrical housing 10b is integrated with the baffle plate 10a.
does not disturb the above-mentioned stable contact state in any way and serves as a watertight passage for the lead wires 14 and 16.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing an example of the moisture control electrode device for the container rotary concrete mixer of this invention, Figure 2 is its plan view, Figure 3 is an enlarged cross-sectional view of the electrode installation location, and Figure 4 is It is an explanatory diagram showing the relationship with related equipment. DESCRIPTION OF SYMBOLS 1... Mixer container, 8... Frame, 9... Electrode, 10... Electrode mounting member, 10a... Breaking plate,
10b...Cylindrical housing, 14, 16...Lead wires.

Claims (1)

[Scope of utility model registration request] It has a mixer container that rotates in a fixed direction, a stirring blade that rotates in the opposite direction between the center of rotation of the mixer container and the inner wall surface of the container, and an electrode mounting member that includes a baffle plate and a cylindrical casing. , one end of the deflection plate is placed close to the inner wall surface of the mixer container where the concrete material stirred by the stirring blades flows into a rotating flow along the mixer container, and the surface of the deflection plate is placed close to the inner wall surface of the mixer container where the concrete material stirred by the stirring blades flows into a rotating flow along the mixer container. The electrode is fixed to a pedestal provided above the container, the electrode is attached to the electrode mounting member so that its surface is almost flush with the surface of the deflection plate, and the lead wire electrically connected to the electrode is attached to the cylindrical casing. Electrode device for moisture adjustment in a container rotary concrete mixer that is led out through the body.