JPH0376357B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method and apparatus for producing grease, and more particularly, to an improvement in temperature control when producing grease. When producing grease, it is important to precisely control the temperature of the mixing system in order to obtain high quality grease. For example, Figure 1 shows an example of an ideal temperature change in a mixing system when manufacturing grease. It is particularly important to convert heating to cooling. By the way, even if you try to realize such a temperature change in each specific mixing system, the actual temperature change in the mixing system will depend on the types and amounts of reactants and additives, their mixing ratio, mixing time, and Since it is influenced by various factors such as the performance of the stirring device and cannot be determined unambiguously, the mixing system can be heated or cooled simply by following the passage of time and based on empirical rules. However, it was extremely difficult to achieve an appropriate temperature change. It is also possible to control the temperature by continuously detecting the temperature of the mixed system, but grease is a mixed system of lubricating base oil (mineral oil or synthetic oil) and oil, and this mixed system is The state is not uniform, the heat transfer state changes successively, and furthermore, the heat transfer coefficient is low and the viscosity is extremely high.
Therefore, it may be difficult to accurately grasp the constantly changing temperature of the mixing system and take prompt action, and controlling the temperature only based on the temperature detected by the stirring device does not necessarily guarantee high quality. Grease was not available. As a result of intensive research into the relationship between the stirring torque when stirring the mixing system, the temperature of the mixing system, and the properties of the finished grease, the inventors of the present invention detected the stirring torque and mixed the grease based on this detected value. The inventors have discovered that by controlling the temperature of the system, ideal temperature changes in the mixing system can be easily achieved and high quality grease can be obtained, and the present invention has been completed. That is, an object of the present invention is to provide a manufacturing method and a manufacturing apparatus that can appropriately control the temperature of a mixing system and easily manufacture high-quality grease. detects the stirring torque of the stirring device that mixes the lubricating base oil and the liquid, and based on this detected value, for example, after the stirring torque suddenly decreases, it changes from slow heating to cooling until it reaches the next maximum value. The purpose is to achieve the above objective by controlling the temperature by, for example, changing the temperature. Further, the device according to the present invention is provided with a temperature control mechanism that connects a torque detector that detects stirring torque to the stirring device and controls the temperature of the stirring device based on the detection value detected by the torque detector. With this temperature control mechanism, for example, after detecting the rate of change in the stirring torque, when the rate of change reaches a predetermined level, the heating of the stirring device is switched to cooling, thereby achieving the above purpose. This is what we are trying to achieve. Embodiments of the present invention will be described below based on the drawings. FIG. 2 shows an embodiment of the grease manufacturing apparatus according to the present invention, in which the stirring device 1 is replaced by the stirring tank 2.
A supply pipe 3 for supplying reactants is provided in the upper part of the stirring tank 2, and a discharge pipe 5 for discharging finished grease is provided in the lower part. A fixed blade 5 is arranged in the stirring tank 2, and a drive shaft 6 is arranged in the center of the stirring tank 2.
is fixed. A temperature control layer 8 such as an electric heater or a heat medium circulation path is provided on the outer periphery of the stirring tank 2 . The drive shaft 6 is connected to an output shaft of a drive source 11 such as a motor, and the output of the drive source 11 is controlled by a drive source control unit 12, and the torque of the output shaft during stirring, in other words, the drive shaft 6 The stirring torque is detected by a torque detector 13 connected to the drive source 11. That is, even if a constant output is given to the drive source 11 by the drive source control unit 12, the drive shaft 6
A reaction force corresponding to the properties is applied to the stirrer, and the torque of the drive shaft 6 actually changes during stirring. This is detected as stirring torque. Torque detector 13
is connected to a temperature control mechanism 21, and in this temperature control mechanism 21, the temperature control layer 8 is controlled, or in other words, the temperature of the stirring device 1 is controlled based on the detected value detected by the torque detector 13. It is configured. The temperature control mechanism 21 detects the rate of change in the stirring torque detected by the torque detector 13.
a change rate detection section 22 that detects by differentiating an input signal from the change rate detection section 22, and a level detection section 23 that generates an output signal when the change rate detected by the change rate detection section 22 reaches a predetermined detection level. and,
It has a control section 24, such as a switch, a variable resistor, or a heat medium flow rate regulating valve, which receives the output signal of the level detection section 23 and controls the temperature adjustment layer 8. The control unit 24 also includes a temperature detection unit 25.
is connected, and a thermometer 26 provided at a predetermined position in the stirring tank 2 is connected to the temperature detection section 25,
When the temperature in the stirring tank 2 is below a predetermined temperature, the control section 24 does not issue a command to the temperature adjustment layer 8 even if it receives the output signal from the level detection section 23. The manufacturing process using this apparatus is, for example, as follows. Step 1: A lubricating base oil is added to fatty acids, etc., which are raw materials for manufacturing soap, and the two are mixed, and the inside of the stirring tank 2 is heated. Step 2: Saponifying the fatty acids and the like to produce soap. During this time, the temperature inside the stirring tank 2 is maintained constant. Step 3: While heating again, lubricating base oil is added and dehydrated and concentrated to promote uniform dispersion of the entire mixed system. Step 4: Switch from heating to cooling. The temperature at the time of transition from step 3 to step 4 is the highest temperature. Step 5: The mixed system is further cooled to grow Setsuken crystals. The relationship between each of these steps and the ideal temperature change is shown in the above-mentioned FIG. 1, but each step can be performed under such temperature changes as follows. That is, temperature control in steps 1 to 5 and control at step transition points other than when transitioning from step 3 to step 4 after the maximum temperature point are as follows:
This is performed manually or automatically based on the temperature inside the stirring tank 2 detected by the temperature detection section 25. However, an extremely quick response is required, and control at the highest temperature point, which is the most important control in obtaining high-quality grease, in other words, control at the transition point from step 3 to step 4 is performed using the torque detector 13. This is done based on the stirring torque detected by . Figure 3A
shows the state of change in the stirring torque detected by the torque detector 13 from the start of operation. At this time, the rate of change of the stirring torque detected by the rate of change detector 22 is shown in FIG. 3B, and the output signal detected by the level detector 23 is shown in FIG. 3C. The output signal shown in FIG. 3C is
The highest level of the rate of change of the stirring torque is determined, and the control section 24 that receives this output signal controls the temperature control layer 8 to change from heating to cooling while this output signal is being generated. At this time, a delay circuit having a predetermined delay time may be used. Note that cooling here includes natural heat dissipation that occurs only when heating is stopped. When the temperature is controlled based on the stirring torque in this way, the stirring torque suddenly decreases until it reaches the next maximum value (the region indicated by the symbol A in Figure 3A). In other words, the maximum temperature point is set during this period and the process is transferred from step 3 to step 4. Note that during an unstable period for a while after the start of operation, the stirring torque tends to become unstable and the rate of change tends to fluctuate. In the following, the output signal from the level detection section 23 is output to the control section 24.
The temperature adjustment layer 8 is not controlled even if the temperature is received. Therefore, measures are taken to prevent malfunctions. This embodiment has the following effects. Unlike the conventional case where temperature control is performed only based on detected temperature, by using temperature control based on stirring torque in combination, it is possible to control the cooling start point at an extremely appropriate time with certainty. Therefore, the temperature of the mixing system can be appropriately controlled without relying solely on empirical rules, and high-quality grease can be easily produced. A specific example is as follows. 12-Hydroxystearate (8.5% by weight), mineral oil (paraffinic 500N, 87.5% by weight), and other additives (4.0% by weight) were used as raw materials and cooled in area A (see Figure 3 A). The time when the stirring torque was started was taken as an experimental example, and the time when cooling was started before the stirring torque reached the minimum value (region B in Figure 3 A) was taken as a comparative example 1, and furthermore, the stirring torque that had once decreased increased. Comparative Example 2 is a case in which cooling is started after the point when the temperature starts to decrease after reaching the maximum value (region C). The following table shows these experimental examples, comparative example 1,
The properties of the finished grease in 2 are shown,
It can also be seen from this table that according to this example, a high-quality grease with low stiffness can be obtained.

[Table] Furthermore, according to this embodiment, since the temperature of the mixing system can be appropriately controlled, unnecessary heating and power can be eliminated, and requests for resource and energy conservation can be met. Furthermore, manufacturing errors can be eliminated, and from this point of view as well, resources can be saved and manufacturing costs can be reduced. In addition, in implementation, the output torque of the drive source 11 may be maintained constant or may be adjusted as appropriate as the manufacturing process progresses. Further, when the rate of change of the stirring torque is detected by the change rate detection section 22, the temperature is adjusted by the control section 24 via the level detection section 23, and cooling is started in the region A of FIG. 3A of the stirring torque. However, other or all times when temperature adjustment is required may also be controlled based on the detected value of the stirring torque. Furthermore, rather than detecting the rate of change in stirring torque,
The temperature of the stirring device 1 may be controlled based on the absolute value of the stirring torque when the output torque (torque at zero load) of the drive source 11 is kept constant, the relative relationship of the stirring torque to the output torque, etc. Further, the stirring device 1 may be of either a pressurized type or a normal pressure type (open type). As described above, according to the present invention, it is possible to provide a manufacturing method and a manufacturing apparatus that can appropriately control the temperature of a mixing system and easily manufacture high-quality grease.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of an ideal temperature change state of a mixing system in grease production, FIG. 2 is a sectional view showing the configuration of an embodiment of a grease production apparatus according to the present invention, B and C are diagrams respectively showing the state of change of the stirring torque, the rate of change of the stirring torque, and the output signal generated by the level detection section based on this rate of change in the embodiment. DESCRIPTION OF SYMBOLS 1... Stirring device, 2... Stirring tank, 5... Fixed blade, 6... Drive shaft, 7... Rotating blade, 8... Temperature adjustment layer, 11... Drive source, 13... Torque detection unit,
21...Temperature control mechanism, 22...Level detection section,
24...Control unit, 25...Temperature detection unit, 26...
thermometer.

Claims (1)

[Scope of Claims] 1. A method for producing grease, which comprises: detecting the stirring torque of a stirring device for mixing lubricating base oil and oil; and controlling the temperature of the stirring device based on the detected value of the stirring torque. . 2. The method for producing grease as set forth in claim 1, characterized in that cooling of the stirring device is started before the stirring torque reaches the next maximum value after it once sharply decreases. 3. A torque detector that detects the stirring torque of a stirring device that mixes the lubricating base oil and the mixture, and a temperature control mechanism that controls the temperature of the stirring device based on the detected value of the detected stirring torque. Grease manufacturing equipment characterized by: 4. In claim 3, the temperature control mechanism includes a change rate detection section that detects a change rate of stirring torque, a level detection section that detects a predetermined level of the change rate, and an output of the level detection section. A grease manufacturing device comprising: a control section that receives a signal and controls a temperature adjustment layer of a stirring device.