AU2008213550A1

AU2008213550A1 - Microwave rotary film concentrator

Info

Publication number: AU2008213550A1
Application number: AU2008213550A
Authority: AU
Inventors: Xiaobing Sun; Haihua Wu; Wensheng Zhang
Original assignee: PHARM TECH TIANJIN CO Ltd
Current assignee: PHARM-TECH(TIANJIN)CO Ltd
Priority date: 2007-02-01
Filing date: 2008-01-10
Publication date: 2008-08-14
Anticipated expiration: 2028-01-10
Also published as: CN101234257A; WO2008095422A1; DE112008000296T5; AU2008213550B2; JP2010517738A; CN101234257B

Description

Microwave rotary film concentrator Field of the invention The invention relates to a concentrating device and more particularly, relates to a microwave rotary film concentrator. Background of the invention Concentrating techniques are widely used in evaporation of liquid and crystallization process of composite, and these techniques include not only concentration under normal pressure, concentration under reduced pressure but also include refrigerated dry. Concentration under reduced pressure is a process in which the pressure is lowered, evaporation temperature of charges is accordingly decreased, and then heat is supplied to the liquid, thus causing evaporation of the solvent and finally improving concentration and facilitating crystallization. Conventional concentration with single effect and concentration with multiple effects suffer from some drawbacks such as long heating time and low heat exchange efficacy. In addition, it is easily subject to decomposition due to exposure of effective components under high temperature for a long time. Also, conventional heat exchanger includes plated structure or arrays of tubes both of which result in difficulties in cleaning surface of the exchanger and possibility of fouling, thereby leading to lowered heat transfer rate as well as significant heat consumption. Moreover, possibly it will result in bumping during evaporating process, as there exist a great number of bubbles, and this always causes loss of liquid material. To obtain more effective concentration, it is necessary to decrease degree of vacuum. This decrease however, further slows down the speed of concentration and causes more component loss. The evaporation speed is proportional largely to evaporation surface area, and accordingly the evaporation speed will be increased if the surface area is increased effectively. Furthermore, it is necessary at present to effectively avoid bubbling during solution evaporation process and reduce loss of effective components. Summary of the invention One object of the invention is to provide a microwave rotary film concentrator which is highly effective yet causes less loss. The microwave rotary film concentrator according to the invention comprises a hermetical tank (1), a rotary evaporator (2), a plurality of microwave generators (3), solution feeding tube (4), a discharging tube for concentrated solution (5), a condenser (6), a plurality of microwave shielding devices (7), a stirring motor (8) and a vacuum system. The hermetical tank forms major part of the microwave rotary film 2 concentrator, and the tank has a cylindrical chamber with an openable lid provided thereon. A sight glass is disposed on the lid for checking boiling state of liquid contained in the concentrator, hence being able to adjust parameters of the concentrator. The microwave shielding device is located on the internal surface of a viewing window. One or more such as two microwave devices are placed on the inner wall of hermetical tank. An opening connected with the condenser is placed in the tank, and the condenser is communicated with the vacuum system via a duct. A rotary film concentrator is set up inside the tank at its center location. The evaporating surface of the evaporator is designed to have a conic or circle shape with a cone angle b of 5-180 degree, and preferably 60-120 degree. The angle between an axis of the evaporator and horizontal plane is 0-90 degree, and more preferably is 20-60 degree. The evaporator may be either solid or hollow. In case of solid evaporator, materials used to construct the evaporator include but is not limited to stainless steel, quartz glass, ceramic, PTFE (Poly-tetra-fluoro-ethene), plastic and so on. While in case of hollow evaporator, materials contacting the evaporating surface of the solution contain but is not limited to stainless steel, ceramic; the filed materials of hollow jacket comprise but is not limited to silicone oil, glycerin, tetra-pod Zinc Oxide Whisker composite, calcined mixture of ferroferrite and iolite with ratio of 30:70 and the like, all these 3 materials bringing good thermal stability and function of preventing vaporization of liquid or solid. Materials forming external layer of a jacket include but is not limited to quartz glass, ceramic, PTFE, plastic or the like, all these materials containing particles which are microwave-permeable, no microwave energy absorbable, highly heat resistive yet with low heat expansion coefficient. Ceramic used to constitute the external layer of the jacket may include alumina, magnesium fluoride and zinc sulfide and the like. Plastic used to constitute the external layer of the jacket may include PE (Polyethylene), PS (Polystyrene) and so on. The external edge of the conical surface of the evaporator has an annular baffle (10) mounted thereon to prevent leakage of liquid out of the evaporator. The angle c between the baffle and conical surface is 5-175 degree, and preferably is 60-120 degree. A groove with semi-circle shaped section and a diameter of 0.5-2cm is formed between the baffle and conical evaporating surface. The evaporator is coupled at its bottom with the stirring motor directly or indirectly. In case of indirect connection, a magnetic stirring device is employed to connect to a magnetic stirring motor located outside of the hermetical tank. While in case of direct connection, a shaft is used to connect to an external stirring motor. A liquid delivery system includes a solution feeding tube, a discharging tube for concentrated solution and corresponding pumps and ducts. An opening 4 towards the discharging tube is defined at a location where the evaporator cone and the baffle are combined together. An angle d of 0-180 degree, preferably 60-120 degree is formed between the opening and the line through the center and vertex of the circle. The distance between the tube opening and evaporating surface is 2-20mm. The discharging tube is tangential to internal surface of the cone and is opposite to rotation direction of the evaporator. A rectangular baffle (11) is disposed at a location 2-20mm far away from a collection tube opening for prevention of liquid leakage. A circular baffle (12) with a diameter of 5-8cm is additionally placed at a location where a vertical line from the uppermost point of the external edge of the evaporator intersections the discharging tube. An inlet of the solution feeding tube parallel to the cone axis is located inside the evaporator and at the center thereof. A rectangular baffle (13) is located at a location which is 0.2-1cm distanced from the inlet of the solution feeding tube. The rectangle baffle (13) is tangential to the circle. Temperature sensors T1 T2 T3 are provided to the solution feeding tube, solution discharging tube and hermetical tank respectively for easily controlling parameters. Microwave shielding devices are mounted on respective external ducts to shield irradiation. The microwave rotary film concentrator of the invention obtains several effects. For example, by way of microwave heating, problems 5 such as low efficiency of stream heating and large size are eliminated, thus effectively causing reduction in size of the concentrator. By way of rotation, the liquid is forced to become film by centrifugal forces, thus effectively leading to increase in evaporating area, reducing heating duration, and improving stability of the substance. This is suitable to concentrate substance which is sensible to heat. At the same time, bubbling of the substance is also prohibited in an effective manner under centrifugal force, and as a result, the applicability of the concentrator is further extended. Using magnetic stirring device as the drive device of the rotary evaporator, problems such as leakage of lubricant oil and destruction of vacuum due to bad sealing quality existed in conventional shaft transmission are overcome. Moreover, the evaporator with smooth surface can be monitored directly. The entire equipment can be disassembled, and therefore can be cleaned completely, thereby avoiding pollution. By way of microwave heating, fouling which would otherwise accumulated by steam heating and which would result in low thermal efficiency, is prevented, thus preventing the increase in energy consumption. The invention overcomes such drawbacks existing in prior art as low evaporating speed, high operation temperature, decomposition of solution due to long time heating as well as difficulties in working under reduced pressure due to bumping of the solution, low energy use 6 efficiency, large size of the equipment and difficulties in cleaning, and thus has a wide prospect of application. Description of the drawings Fig. 1 shows a side elevation view of an embodiment of the invention; and Fig. 2 shows a front view of the embodiment of the invention. Preferred embodiments of the invention The invention is described below in great detail with reference to some embodiments which are only illustrative but not intended to limit the invention. Embodiment 1 The microwave rotary film concentrator includes a hermetical tank (1), a rotary evaporator (2), a plurality of microwave generators (3), solution feeding tube (4), a discharging tube for concentrated solution (5), a condenser (6), a plurality of microwave shielding device (7), a stirring motor (8) and a vacuum system. The hermetical tank forms major part of the microwave rotary film concentrator, and the tank has a cylindrical chamber with an openable lid provided thereon. A sight glass is disposed on the lid. A microwave shielding device is located on the internal surface of a viewing window. 7 One microwave device is located on the inner wall of the hermetical tank. An opening connected with the condenser is defined in the tank, and the condenser is communicated with the vacuum system via a duct. A rotary film concentrating device is disposed inside the tank at its center location. The evaporating surface of the evaporator is designed to have a conic shape with a cone angle b of 180 degree. The angle a between an axis of the evaporator and horizontal plane is 90 degree. The evaporator is solid and made of stainless steel. The external edge of the conical surface of the evaporator has an annular baffle (10) mounted thereon. The angle c between the baffle and conical surface is 60 degree. A groove with semi-circle shaped section and a diameter of 2cm is formed between the baffle and conical evaporating surface. The evaporator is coupled at its bottom indirectly by a magnetic stirring device to a magnetic stirring motor located outside of the hermetical tank. A liquid delivery system includes a solution feeding tube, a concentrated solution discharging tube and corresponding pumps and ducts, an opening of the discharging tube located at a location where the evaporator cone and the baffle are combined together, wherein, an angle d of 120 degree is formed between the opening and the line through the center and vertex of the circle, and the distance between the tube opening and evaporating surface is 0.2m. The discharging tube is tangential to internal surface of the cone and is opposite to rotation 8 direction of the evaporator. A rectangular baffle (11) is disposed at a location 0.2m far away from a collection tube opening. A circular baffle (12) with a diameter of 8cm is additionally placed at a location where a vertical line from the uppermost point of the external edge of the evaporator intersections the discharging tube. An inlet of the solution feeding tube parallel to the cone axis is located inside the evaporator and at the center thereof. A rectangular baffle (13) whose long plane is tangential to the circle, is located at a location which is 0.2cm distanced from the inlet of the solution feeding tube. Temperature sensors T1 T2 T3 are provided inside of the solution feeding tube, solution discharging tube and hermetical tank respectively. Microwave shielding devices are mounted on respective external ducts. Embodiment 2 The microwave rotary film concentrator includes a hermetical tank (1), a rotary evaporator (2), a plurality of microwave generators (3), solution feeding tube (4), a concentrated solution discharging tube (5), a condenser (6), a microwave shielding device (7), a stirring motor (8) and a vacuum system. The hermetical tank forms major part of the microwave rotary film concentrator, and the tank is a cylindrical chamber with an openable lid provided thereon. A sight glass is disposed on the lid. A microwave shielding device is located on the internal surface of a viewing window 9 of the sight glass. Two microwave devices are located on the inner wall of the hermetical tank. An opening connected with the condenser is defined in the tank, and the condenser is communicated with the vacuum system via duct. A rotary film concentrating device is disposed inside the tank at its center location. The evaporating surface of the evaporator is designed to have a conic shape with a cone angle b of 60 degree. The angle a between an axis of the evaporator and horizontal plane is 0 degree. The evaporator is hollow and made of stainless steel. The hollow jacket is filled with tetra-pod Zinc Oxide Whisker composite, while the outer layer of the jacket is sealed with ceramic. The external edge of the conical surface of the evaporator has an annular baffle (10) mounted thereon, and the angle c between the baffle and conical surface is 120 degree. A groove with semi-circle shaped section and a diameter of 0.5cm is formed between the baffle and conical evaporating surface. The evaporator is coupled at its bottom indirectly by a magnetic stirring device to a magnetic stirring motor located outside of the hermetical tank. A liquid delivery system includes a solution feeding tube, a discharging tube for concentrated solution and corresponding pumps and ducts. An opening towards the discharging tube is defined at a location where the evaporator cone and the baffle are combined together. An angle d of 180 degree is formed between the opening and the line through the center and vertex of circle. The 10 distance between the tube opening and evaporating surface is 2cm. The discharging tube is tangential to internal surface of the cone and is opposite to rotation direction of the evaporator. A rectangular baffle (11) is disposed at a location 1cm far away from a collection tube opening. A circular baffle (12) with a diameter of 5cm is additionally placed at a location where a vertical line from the uppermost point of the external edge of the evaporator intersections the discharging tube. An inlet of the solution feeding tube parallel to the cone axis is located inside the evaporator and at the center thereof. A rectangular baffle (13) whose long plane is tangential to the circle, is located at a location which is 2cm distanced from the inlet of the solution feeding tube. Temperature sensors T1 T2 T3 are provided to the solution feeding tube, solution discharging tube and hermetical tank respectively for easily controlling parameters. Microwave shielding devices (7) are mounted in respective external ducts. Embodiment 3 The microwave rotary film concentrator includes a hermetical tank (1), a rotary evaporator (2), a plurality of microwave generators (3), solution feeding tube (4), a discharging tube for concentrated solution (5), a condenser (6), a plurality of microwave shielding device (7), a stirring motor (8) and a vacuum system. I ! The hermetical tank forms major part of the microwave rotary film concentrator, and the tank has a cylindrical chamber with an openable lid provided thereon. Two sight glasses are disposed on the lid. There is a microwave shielding device located on the internal surface of a viewing window of the sight glass. One microwave device is fixed inside the solution feeding tube which locates outside of the hermetical tank. There is an opening connected with the condenser in the tank, and the condenser is communicated with the vacuum system via a duct. A rotary film concentrating device is disposed inside the tank at its center location. The evaporating surface of the evaporator is designed to have a conic shape with a cone angle b of 120 degree. The angle a between an axis of the evaporator and horizontal plane is 30 degree. The evaporator is solid and its evaporating surface is made of PTFE (Poly-tetra-fluoro-ethene). The external edge of the conical surface of the evaporator has an annular baffle (10) mounted thereon. The angle c between the baffle and conical surface is 60 degree. A groove with semi-circle shaped section and a diameter of 2cm is formed between the baffle and conical evaporating surface. The evaporator is coupled at its bottom directly by a shaft to a stirring motor located outside of the hermetical tank. A liquid delivery system includes a solution feeding tube, a concentrated solution discharging tube and corresponding pumps and ducts. An opening towards the discharging tube is defined 12 at a location where the evaporator cone and the baffle are combined together. An angle d of 60 degree is formed between the opening and the line through the center and vertex of the circle. The distance between the tube opening and evaporating surface is 0.2cm. The discharging tube is tangential to internal surface of the cone and is opposite to rotation direction of the evaporator. A rectangular baffle (11) is disposed at a location 1cm far away from a collection tube opening. A circular baffle (12) with a diameter of 3cm is additionally placed at a location where a vertical line from the uppermost point of the external edge of the evaporator intersections the discharging tube. An inlet of the solution feeding tube parallel to the cone axis is located inside the evaporator and at the center thereof. A rectangular baffle (13) whose long plane is tangential to the circle, is located at a location which is 1cm distanced from the inlet of the solution feeding tube. Temperature sensors T1 T2 T3 are provided to the solution feeding tube, solution discharging tube and hermetical tank respectively for easily controlling parameters. Microwave shielding devices (7) are mounted on respective external ducts. 13

Claims

1. A microwave rotary film concentrator comprises a hermetical tank (1), a rotary evaporator (2), a plurality of microwave devices (3), solution feeding tube (4), a discharging tube for concentrated solution (5), a condenser (6), a plurality of microwave shielding device (7), a stirring motor (8) and a vacuum system, wherein the hermetical tank forms major part of said microwave rotary film concentrator, and the microwave devices are provided at the inner wall of the hermetical tank; an opening connected with the condenser is located on the body of tank, and the condenser is communicated with the vacuum system via a duct; a rotary film concentrating device is disposed inside the tank at its center location; the external edge of the evaporator surface has an annular baffle (10) mounted thereon; an opening towards the discharging tube is defined at a location where the evaporator cone and the baffle are combined together; the discharging tube is tangential to the inner surface of the evaporator; the evaporator is coupled to a stirring motor by direct manner or indirect manner; and microwave shielding devices are mounted on respective external ducts.

2. The microwave rotary film concentrator according to claim 1, wherein the evaporating surface of the rotary evaporator (2) is 14 designed to have a conic or circle shape with a cone angle b of 5-180 degree; and the angle between an axis of the rotary evaporator (2) and a horizontal plane is 0-90 degree.

3. The microwave rotary film concentrator according to claim 1, wherein the evaporating surface of the rotary evaporator (2) is designed to have a conic shape with a cone angle b of 60-120 degree; and the angle between an axis of the rotary evaporator (2) and a horizontal plane is 20-60 degree.

4. The microwave rotary film concentrator according to claim 2 or 3, wherein the rotary evaporator (2) is solid and made of any one or more of stainless steel, quartz glass, ceramic, PTFE and plastic.

5. The microwave rotary film concentrator according to claim 2 or 3, wherein the rotary evaporator (2) is hollow; and the evaporating surface contacting the solution is made of stainless steel or ceramic or combination thereof; wherein the hollow jacket is filled with one or more of silicone oil, glycerin, tetra-pod Zinc Oxide Whisker composite, calcined mixture of ferroferrite and iolite (with a mixture ratio of 30:70); and wherein the materials of the external layer of the jacket selected from any one or two of stainless steel, quartz glass, ceramic, PTFE and plastic.

6.The microwave rotary film concentrator according to any one of claims 1-3, wherein the rotary evaporator (2) has a concentrator 15 baffle (10) mounted on the edge of its conical evaporating surface, and the angle c between the conical evaporating surface and the baffle is 5-175 degree.

7. The microwave rotary film concentrator according to any one of claims 1-3, wherein the rotary evaporator (2) is connected indirectly with an external stirring motor (8) through a magnetic stirring device and locates inside the center of the hermetical tank.

8. The microwave rotary film concentrator according to any one of claims 1-3, wherein the hermetical tank has an openable lid, and a sight glass (9) is disposed on the lid.

9. The microwave rotary film concentrator according to any one of claims 1-3, wherein the angle d between a collection opening of the discharging tube of the rotary evaporator (2) and a vertical line is

60-120 degree. 10.The microwave rotary film concentrator according to claim 1, wherein the evaporating surface of the rotary evaporator (2) is designed to have a conic shape with a cone angle b of 60-120 degree; the angle a between an axis of the rotary evaporator (2) and a horizontal plane is 20-60 degree; the rotary evaporator (2) has a concentrator baffle (10) mounted on the edge of its conical evaporating surface, and the angle c between the conical evaporating surface and the baffle is 6-120 degree; the angle d between an 16 collection tube of the discharging tube of the rotary evaporator (2) and a vertical line is 60-120 degree; the rotary evaporator (2) is connected indirectly with an external stirring motor (8) through a magnetic stirring device and locates inside the center of the hermetical tank; the hermetical tank (1) has an openable lid provided thereon, and a sight glass (9) is disposed on the lid. 17