WO2022022064A1 - Granulation system for traditional chinese medicine extract powder for treating cervical spine disease, and method - Google Patents

Abstract

A granulation system for a traditional Chinese medicine extract powder for treating a cervical spine disease, and a method, which belong to the field of traditional Chinese medical granulation technology, said system comprising a mixing apparatus (1), a low temperature drying device (2), and a dry granulation device (3) which are sequentially connected; the mixing apparatus comprises an upper mixing device and a lower mixing device, a material feed opening is arranged on a material feed end of the upper mixing device, a material outlet opening is arranged on a material outlet end of the upper mixing device, the lower mixing device is located below the material outlet opening of the material outlet end of the upper mixing device, a material outlet channel (4) is arranged within the lower mixing device, and a top part of the material outlet channel (4) is in communication with the material outlet opening of the upper mixing device. After raw materials undergo ambient temperature and low temperature mixing, low temperature freeze-drying is performed, and subsequently dry granulation is performed. Granules obtained from granulation possess good flowability and compressibility.

Description

A kind of traditional Chinese medicine extract powder granulation system and method for treating cervical spondylosis technical field

The invention belongs to the technical field of traditional Chinese medicine granulation, and in particular relates to a traditional Chinese medicine extract powder granulation system and method for treating cervical spondylosis.

Background technique

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not necessarily be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

In the existing granulation method, the extract is filtered and boiled to remove large particles to obtain fine powder, and the boiling process is used to increase the fluidity, and then spray granulation is performed. However, after this process, some effective substances contained in the traditional Chinese medicine are removed, which affects the retention effect of the medicinal effect.

However, in the complex preparation method of traditional Chinese medicine components, different components are required to be extracted separately, and then combined together for granulation, and the physical states of the various extracts before being mixed together are different, such as fluidity and Compressibility, powder structure characteristics, etc. And due to different types of traditional Chinese medicines, the physical properties of the extracts obtained by different methods are different.

Therefore, if the existing spray granulation method is adopted, due to the different fluidity of the pharmaceutical ingredients in the process of flowing, the obtained powder composition is not uniform, and it is easy to agglomerate and agglomerate. Due to the non-uniform composition, the structure of the obtained dry powder is non-uniform, and the particle size of the particles is non-uniform. If the fluidity of the extract is improved through complex processing technology, it will affect the retention of the medicinal effect and the quality of the Chinese medicine granules.

SUMMARY OF THE INVENTION

For the problems existing in the above-mentioned prior art, the purpose of this invention is to provide a kind of Chinese medicine extract powder granulation system and method for the treatment of cervical spondylosis. According to the fluidity, compressibility and powder structure characteristics of traditional Chinese medicine extracts, a granulation system and method are proposed, so that the obtained traditional Chinese medicine granules have a uniform quality and improve the retention rate of the active ingredients of the medicine.

In order to solve the above technical problems, the technical scheme of the present invention is:

A first aspect, a traditional Chinese medicine extract powder granulation system for the treatment of cervical spondylosis, comprising a mixing device, a low-temperature drying device, and a dry granulation device connected in sequence, and the mixing device includes an upper mixing device and a lower mixing device. The feeding end is provided with a feeding port, the discharging end of the upper mixing device is provided with a discharging port, the lower mixing device is located below the discharging port of the discharging end of the upper mixing device, and a discharging channel is set in the lower mixing device. The discharge port of the upper mixing device is connected, and a cooling structure is arranged in the lower mixing device.

The traditional Chinese medicine extract for the treatment of cervical spondylosis involves two clear pastes and one Panax notoginseng powder and volatile oil. By using the above system, a kind of better fluidity and certain compressibility can be obtained. The mixture is relatively uniform.

Clear paste is a miscible dispersion, a complex system of organic compounds. Miscible dispersions containing eutectic mixtures, solid solutions, amorphous precipitates, and the like. Such miscible dispersions have larger surface areas and surface energies, thus increasing the properties of moisture absorption and blocking.

The properties of the ointment obtained by different preparation methods of the ointment are different, and the properties of the ointment obtained from the traditional Chinese medicine with different components are also different.

The surface energy of the mixture is reduced by the mixing device. After the surface energy is reduced, the wettability of the mixture is better, so that the material in the mixture is more uniform and has better fluidity, so the granulation quality is better.

The second aspect, the granulation method of Chinese medicine extract powder for the treatment of cervical spondylosis, the concrete steps are:

The raw materials and auxiliary materials are mixed at normal temperature and low temperature in turn;

The mixture is freeze-dried at low temperature;

The mixture obtained by low temperature freeze drying is dry granulated.

One or more technical solutions of the present invention have the following beneficial effects:

Based on the physical properties of the middle components of the traditional Chinese medicine extract, and considering its fluidity and compressibility, a granulation method suitable for this traditional Chinese medicine was obtained.

After the mixing process of the granulation system, the difference in fluidity and compressibility of different extracts is satisfied, and the fluidity of the mixture is improved from the point of view of the surface energy that affects the fluidity of the mixture.

The raw materials and auxiliary materials are comprehensively proportioned, so that the fluidity and compressibility of the mixture are within a suitable range, which is conducive to the obtained granulation particles, and has better surface smoothness and particle uniformity.

Guarantee the quality and clinical efficacy of traditional Chinese medicine granules, improve the granulation efficiency, and provide a reliable and fast technical platform for the research of traditional Chinese medicine molding process and pharmaceutical prescription. , It has broad application prospects in promoting the export of traditional Chinese medicine preparations.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present application, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

Fig. 1 is the structure diagram of the traditional Chinese medicine extract powder granulation system for the treatment of cervical spondylosis of the embodiment;

Fig. 2 is the top structure view of the upper mixing device of the embodiment;

Fig. 3 is the cross-sectional structure diagram of the discharge channel of the embodiment;

Among them, 1. mixing device, 2. low temperature drying equipment, 3. dry granulation equipment, 4. discharging channel, 5. mixing channel, 6. feeding channel, 7. cooling chamber, 8. cooler.

detailed description

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

A first aspect, a traditional Chinese medicine extract powder granulation system for the treatment of cervical spondylosis, comprising a mixing device, a low-temperature drying device, and a dry granulation device connected in sequence, and the mixing device includes an upper mixing device and a lower mixing device. The feeding end is provided with a feeding port, the discharging end of the upper mixing device is provided with a discharging port, the lower mixing device is located below the discharging port of the discharging end of the upper mixing device, and a discharging channel is set in the lower mixing device. The discharge port of the upper mixing device is connected, and a cooling structure is arranged in the lower mixing device.

In some embodiments of the present invention, the discharge channel is arranged vertically, the cross-section of the discharge channel is double circles, the double circles are partially overlapped, and the outer sides of the double circles have convex structures of different sizes. The material channel is a hollow tube structure.

In some embodiments of the present invention, the upper mixing device includes a middle mixing channel and several oppositely arranged feeding channels on both sides of the mixing channel, the feeding channels are located above the sides of the mixing channel and are inclined in the axial direction perpendicular to the mixing channel set up.

In some embodiments of the present invention, several feeding channels are provided independently, and a screw conveyor is provided in the mixing channel.

In some embodiments of the present invention, the lower mixing device includes a discharge channel and a cooling chamber, and the discharge channel is located in the cooling chamber and is sealed with the cooling chamber.

In some embodiments of the present invention, the mixing device further includes a cooler, the cooler is arranged below the upper mixing device, on one side of the upper mixing device, and the cooler communicates with the cooling chamber through a medium pipe.

As shown in Figure 1, in the traditional Chinese medicine extract powder granulation system, each raw material (Pueraria Radix Paeoniae Alba, Chuanqiongyanhu Suoqing Cream, Panax notoginseng powder) is fully mixed first through the mixing device 1, and the mixed materials pass through the lower mixing equipment. , In the lower mixing equipment, the mixed material passes through the shrinkage of the discharge channel and the cooling effect of the cooling equipment, the material in the mixed material has the effect of shrinkage, the surface energy is reduced, the fluidity is enhanced, and the fluidity-enhanced mixture passes through the low-temperature drying equipment. 2. After drying, the dry granulation equipment 3 performs granulation. During the granulation process, the mixing effect of the materials is better, which is beneficial to the obtained granules with better uniformity.

As shown in Figure 2, the top of the upper mixing device of the mixing device is an open or closed structure. A feed port is set at a position opposite to the side wall of the upper mixing device in the feed channel, so that feeding can be carried out through the feed port. Or if it is an open setup, this allows feeding directly into the feed channel.

As shown in Figure 2, the mixture is driven by the screw conveyor to move. When the mixture moves to the top of the discharge channel, under the action of the gravity of the mixture, it enters the discharge channel, between the top of the discharge channel and the upper mixing device. An opening is provided at the junction.

As shown in Figure 3, the mixed material passes through the discharge channel 4, which is equivalent to extruding the mixed material. The upper mixing device is located above the lower mixing device, and the mixed material passes downward through the discharge channel 4 under the action of gravity. Under the constraints of gravity and the discharge channel, the material passes through the discharge channel 4. The outlet channel 4 is designed in the shape of a double circle, and the double circles are partially overlapped. In this way, the materials in each circular channel are in contact with each other at the overlapping part, and the outer sides of the double circles have convex structures of different sizes. In the cleaning process, the shape of the discharge channel 4 through which the mixed cleaning solution passes is variable, so that the surface of the formed agglomeration structure is rougher and more variable, which is beneficial to the tendency of the mixture to reduce the surface energy. And after the mixture passes through the discharge channel, the mixture is further mixed evenly.

As shown in FIG. 2 , each feeding channel 6 and the mixing channel 5 are arranged obliquely, so that the material can be inclined to fall into the mixing channel 5, and the two opposite feeding channels 6 collide and overlap each other in the mixing channel 5, which is beneficial to improve the mixing. The effect is that the feeding of the adjacent or opposite feeding channels 6 is different, so that the two kinds of clear paste and Panax notoginseng powder can be wrapped and mixed with each other. Avoid wrapping too much clear cream or Panax notoginseng powder in one location.

The cooling chamber 7 is filled with a cooling medium, so that the discharge channel 4 can be cooled. The cooler 8 is connected to the cooling chamber 7, and the cooling liquid can be pumped into the cooling chamber. .

The mixture contributes to the reduction of the surface energy at low temperature and improves the fluidity.

Second aspect, utilize the Chinese medicine extract powder granulation method of the above-mentioned Chinese medicine extract powder granulation system for the treatment of cervical spondylosis, and the concrete steps are:

The raw materials and auxiliary materials are sequentially mixed at normal temperature and low temperature;

The mixture is freeze-dried at low temperature;

The mixture obtained by low temperature freeze drying is dry granulated.

In some embodiments of the present invention, the raw materials are successively mixed at normal temperature and low temperature. When mixing at normal temperature, in each feeding channel of the upper mixing device, the feeding of two adjacent feeding channels is different, and the opposite two feeding channels have different feeding materials. The feeding of each feeding channel is different, and the low temperature is 5-18°C; preferably: 8-15°C; more preferably 10-12°C.

In some embodiments of the present invention, the auxiliary materials are dextrin and carboxymethyl cellulose, and the mass ratio of dextrin and carboxymethyl cellulose is 10:3-5; preferably 10:4.

In some embodiments of the present invention, the mass ratio of the total mass of each raw material to the total mass of the auxiliary materials is 10:3-6; preferably 10:5. The total mass of each raw material and the mass ratio of auxiliary materials affect the fluidity and compressibility of the mixture, and indirectly affect the uniformity and surface morphology of the obtained particles.

In some embodiments of the present invention, each raw material includes Pueraria lobatae clearing paste, Chuanqiongyanhusuo clearing paste, and Panax notoginseng powder, and the particle size of Panax notoginseng powder is 100-120 mesh. For special raw materials, different proportions of auxiliary materials are added to the raw materials, and different treatment methods can be set to obtain better granulation effect.

In some embodiments of the present invention, the granulated granules are mixed with Qiang Huo Wei Ling Xian volatile oil to obtain a product.

In some embodiments of the present invention, the vacuum degree of low-temperature freeze-drying is -0.1～-0.5MPa, and the temperature is -10～-15°C; preferably, the vacuum degree of low-temperature freeze-drying is -0.2～-0.5MPa, and the temperature It is -10～-12℃.

In some embodiments of the present invention, dry granulation is carried out using a dry granulator, and the granulation conditions are: the main pressure is 5-8 MPa, the side pressure is 0.5-2 MPa, and the rolling speed is 10- 30 rpm, and the propeller speed is 50-80 rpm.

Each intermediate product obtained by the pharmaceutical preparation method in CN1228071C, wherein step (1) pulverizes Panax notoginseng powder into 100-120 mesh fine powder (panax notoginseng powder of the present invention); step (2) extracts volatile oil from Qianghuo and Weilingxian , the distilled aqueous solution is collected in another device, the medicinal residues are decocted with water for 1h, and the filtrate is for subsequent use; step (3) Pueraria lobata and Paeonia lactiflora are decocted twice with water, the first time is 2 hours, the second time is 1 hour, the filtrate and the above two aqueous solutions Merge, concentrate, alcohol precipitation, reclaim ethanol, become clear paste with relative density 1.25-1.30 (50 ℃) after concentrating (Pueraria Radix Paeoniae Alba clear paste of the present invention); Step (4) Zhongchuan Qiong, Corydalis fragrans are extracted with ethanol reflux, and the residue is discarded , the extracting solution recovers ethanol, and is concentrated into a clearing paste with a relative density of 1.25-1.30 (50° C.) (the Chuanqiongyanhusuo clearing paste of the present invention). 1-15 copies of Panax notoginseng, 3-20 copies of Chuanqiong, 2-15 copies of Yanhusuo, 3-20 copies of Baishao, 4-25 copies of Weilingxian, 3-20 copies of Gegen, and 4-25 copies of Qianghuo.

Below in conjunction with embodiment, the present invention is further described

Example 1

The Pueraria lobatae clearing paste, the Chuanqiongyanhusuo clearing paste, the Panax notoginseng powder and the auxiliary materials were first mixed at room temperature in a mixing device, and then mixed at 10 ° C, and the obtained mixture was freeze-dried at a low temperature (-0.3 MPa, -12 ° C) ); the mixture obtained by low temperature freeze drying is carried out dry granulation (main pressure is 6 MPa, side pressure is 1 MPa, roll speed is 20 rev/min, propeller speed is 60 rev/min).

The mass ratio of the total mass of Pueraria Baishao Qing ointment, Chuanqiong Yanhusuo Qing ointment and Panax notoginseng powder to the auxiliary materials is 10:5, the auxiliary materials are dextrin and carboxymethyl cellulose, and the mass ratio of dextrin and carboxymethyl cellulose in the auxiliary materials 10:4.

Example 2

The pueraria white peony root clearing paste, Chuanqiongyanhusuo clearing paste, Panax notoginseng powder and auxiliary materials were first mixed at room temperature in a mixing device, and then mixed at 12 ° C, and the obtained mixture was freeze-dried at a low temperature (-0.4MPa, -10 °C ); the mixture obtained by low temperature freeze drying is carried out dry granulation (the main pressure is 7 MPa, the side pressure is 1.5 MPa, the rotational speed of the roll is 25 rpm, and the rotational speed of the propeller is 70 rpm).

The mass ratio of the total mass of Gegen Baishao Qing ointment, Chuanqiong Yanhu Suo Qing ointment and Panax notoginseng powder to the auxiliary materials is 10:4, the auxiliary materials are dextrin and carboxymethyl cellulose, and the mass ratio of dextrin and carboxymethyl cellulose in the auxiliary materials 10:3.

Example 3

The pueraria white peony root clearing paste, Chuanqiongyanhusuo clearing paste, Panax notoginseng powder and auxiliary materials were first mixed at room temperature in a mixing device, and then mixed at 11 °C, and the obtained mixture was freeze-dried at low temperature (-0.5MPa, -11 °C). ); the mixture obtained by low-temperature freeze-drying is carried out dry granulation (main pressure is 8 MPa, side pressure is 2 MPa, roll speed is 30 rev/min, propeller speed is 75 rev/min).

The mass ratio of the total mass of Gegen Baishao Qing ointment, Chuanqiong Yanhu Suo Qing ointment and Panax notoginseng powder to the auxiliary materials is 10:3, the auxiliary materials are dextrin and carboxymethyl cellulose, and the mass ratio of dextrin and carboxymethyl cellulose in the auxiliary materials 10:5.

Comparative Example 1

The Pueraria lobatae clearing paste, the Chuanqiongyanhusuo clearing paste, the Panax notoginseng powder and the auxiliary materials were first mixed at room temperature in a mixing device, and then mixed at 10 ° C, and the obtained mixture was freeze-dried at a low temperature (-0.3 MPa, -12 ° C) ); the mixture obtained by low temperature freeze drying is carried out dry granulation (main pressure is 6 MPa, side pressure is 1 MPa, roll speed is 20 rev/min, propeller speed is 60 rev/min).

The mass ratio of the total mass of Gegen Baishao Qing ointment, Chuanqiong Yanhu Suo Qing ointment and Panax notoginseng powder to the auxiliary materials is 10:8, the auxiliary materials are dextrin and carboxymethyl cellulose, and the mass ratio of dextrin and carboxymethyl cellulose in the auxiliary materials 10:7.

Comparative Example 2

Compared with Example 1, the particle size of Panax notoginseng powder is 150 meshes, and other granulation methods are the same as those in Example 1.

Test Example 1

Fluidity Determine the fluidity of the clear paste according to the method specified in GB8077. Fluidity of Example 1 and Example 3, and Comparative Example 1. The results shown in Table 1 are obtained. As shown in Table 1, the mixing effect of the mixing device of Example 1 can be obtained. The obtained mixed powder is relatively uniform and has good fluidity. After the addition ratio of the adjuvant in Comparative Example 1 was changed, the fluidity decreased relative to that of Example 1. In Comparative Example 2, the particle size of the raw materials changed, and the fluidity of the obtained mixture became poor, so the fluidity of different raw materials was different.

In Table 1, no cooling chamber is provided, which is based on Example 1, in the mixing device, the mixture is not cooled. Compared with the mixture of Example 1, the fluidity of the mixture without the cooling cavity was slightly reduced.

Table 1 Mobility

Fluidity(mm) Before entering the mixing unit After the mixing device flows out No cooling chamber provided Pueraria Root + Bai Shao Qing Cream 180     Chuanqiong + Yanhu Suo Qing ointment 160     Mixed clear cream + Panax notoginseng powder 140 250 (Example 1) 240 Mixed clear cream + Panax notoginseng powder 140 200 (Comparative Example 1)   Mixed clear cream + Panax notoginseng powder 140 210 (Comparative Example 2)  

Test Example 2

The materials obtained after freeze-drying in Example 1 and Comparative Example 1 were compressed using a tablet machine, and the powder obtained by drying each raw material by a method of spray drying was compressed into tablets. The clear paste was mixed, boiled for 5 minutes, then added with Panax notoginseng powder and auxiliary materials (the ratio of each raw material and auxiliary material was the same as that in Example 1), and then sprayed and granulated, and the results were shown in Table 2. It can be seen from Figure 2 that the freeze-dried mixture in Example 1 has better compressibility, better viscosity and punchability than spray drying, and better brittle hardness of the powder. In Comparative Example 1, the mixing ratio of the auxiliary materials was changed, and although it had better hardness, the viscosity and punchability were reduced compared with that of Example 1.

Table 2 Compressibility

Test Example 3

Example 1, Comparative Example 1 and the spray drying method and the comparison of the surface morphology of the particles obtained after dry granulation, as shown in Table 3, the spray drying method is the same as the spray drying method in Test Example 2, and the dry granulation method is the same. The operating conditions were the same as those of Example 1. It can be obtained from Table 3 that the particle size after granulation in Example 1 is uniform, indicating that the granulation method of Example 1 improves the granulation quality. The granules obtained by spray drying and dry granulation methods vary in size, with a small amount of agglomeration. The diameter of the particles obtained in Comparative Example 1 is relatively regular, but there are some small pits on the surface of the particles, which affect the overall granulation effect.

Table 3 Powder structure

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

A traditional Chinese medicine extract powder granulation system for treating cervical spondylosis, characterized in that the specific steps are: comprising a mixing device, a low-temperature drying device, and a dry granulation device connected in sequence, and the mixing device comprises an upper mixing device and a lower mixing device, The feeding port of the upper mixing device is provided with a feeding port, the discharging end of the upper mixing device is provided with a discharging port, the lower mixing device is located below the discharging port of the discharging end of the upper mixing device, and a discharging channel is set in the lower mixing device, and the material is discharged. The top of the channel is communicated with the discharge port of the upper mixing device, and a cooling structure is arranged in the lower mixing device. The traditional Chinese medicine extract powder granulation system for treating cervical spondylosis according to claim 1, characterized in that: the discharge channel is arranged vertically, the cross-section of the discharge channel is a double circle, the double circle parts overlap, and the double circle The outer side of the tube has a raised structure of different sizes, and the discharge channel is a hollow tube structure. The traditional Chinese medicine extract powder granulation system for treating cervical spondylosis according to claim 1, wherein the upper mixing device comprises a middle mixing channel and a plurality of oppositely arranged feeding channels on both sides of the mixing channel, and the feeding channel is located in the mixing channel Above the side of the mixing channel, it is inclined in the axial direction perpendicular to the mixing channel; preferably, several feeding channels are independently arranged, and a screw conveyor is arranged in the mixing channel. The traditional Chinese medicine extract powder granulation system for treating cervical spondylosis according to claim 1, wherein the lower mixing device comprises a discharge channel and a cooling cavity, and the discharge channel is located in the cooling cavity and is sealed with the cooling cavity. The traditional Chinese medicine extract powder granulation system for treating cervical spondylosis according to claim 1, characterized in that: the mixing device further comprises a cooler, the cooler is arranged below the upper mixing device, on one side of the upper mixing device, the cooler is connected to a cooler. The cooling chambers are communicated through medium pipes. Utilize any described Chinese medicine extract powder granulation system for the treatment of cervical spondylosis of claims 1-5 to carry out the method for Chinese medicine extract powder granulation, it is characterized in that: the concrete steps are: The raw materials and auxiliary materials are sequentially mixed at normal temperature and low temperature; The mixture is freeze-dried at low temperature; The mixture obtained by low temperature freeze drying is dry granulated. The method for granulating traditional Chinese medicine extract powder according to claim 6, characterized in that: the raw materials are successively mixed at normal temperature and low temperature, and the low temperature temperature is 5-18°C; preferably: 8-15°C; further It is preferably 10-12°C. The method for granulating traditional Chinese medicine extract powder as claimed in claim 6, characterized in that: the auxiliary materials are dextrin and carboxymethyl cellulose, and the mass ratio of dextrin and carboxymethyl cellulose is 10:3-5; preferably 10:4. The method for granulating traditional Chinese medicine extract powder as claimed in claim 6, characterized in that: the mass ratio of the total mass of each raw material to the total mass of auxiliary materials is 10:3-6; preferably 10:5; The raw materials include Pueraria Radix Paeoniae Alba clearing paste, Chuanqiongyanhusuo clearing paste, Panax notoginseng powder; Or, the granulated granules are mixed with Qiang Huo Wei Ling Xian volatile oil to obtain a product. The method for granulating traditional Chinese medicine extract powder as claimed in claim 6, characterized in that: the vacuum degree of low temperature freeze drying is -0.1～-0.5MPa, and the temperature is -10～-15 ℃; The vacuum degree is -0.2～-0.5MPa, and the temperature is -10～-12℃; Or, dry granulation is carried out using a dry granulator, and the granulation conditions are: the main pressure is 5-8 MPa, the side pressure is 0.5-2 MPa, the rolling speed is 10-30 rpm, the propeller The speed is 50-80 rpm.

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