WO2008006291A1

WO2008006291A1 - A wholly sealed microwave sulfur lamp

Info

Publication number: WO2008006291A1
Application number: PCT/CN2007/002011
Authority: WO
Inventors: Zhenda Li
Original assignee: Zhenda Li
Priority date: 2006-07-07
Filing date: 2007-06-27
Publication date: 2008-01-17
Also published as: CN201004452Y

Abstract

Disclosed is a wholly sealed microwave sulfur lamp, wherein a heat- conductive gel or a heat-conductive oil or a heat-conductive resin is utilized as a medium to conduct the heat, which is produced therein by the magnetron and the direct current high voltage producing circuitry, plus a pump for promoting the flow of said heat-conducting fluid to transfer the heat directly into the atmosphere through the metal out cover of the lamp as its natural heat radiator, with no need of compulsive wind blasting cooling for magnetron and the direct current high voltage producing circuitry including the high voltage pack and the electronic frequency conversion power supply.

Description

A Wholly Sealed Microwave Sulfur Lamp

Technical Field

The present invention relates to a lighting device, more particularly to a wholly sealed microwave sulfur lamp.

Background Art

In a microwave sulfur lamp, light with a continuous spectrum is generated from luminescent material, sulfur, inside a quartz bulb, of which transitions between molecular levels are excited by using microwave of 2450 MHz. A microwave sulfur lamp has many advantages, such as having a wide optical spectrum with low UV and IR contamination, good effects of vision, and a sustaining high luminous flux rate with no appreciable change over its whole lifetime, therefore, it can be used in the vast fields of outdoor lighting, such as, for highways, streets, wharves, bridges, tunnels, advertisements, airports, scenery illuminations, public places and occasions, special sites and regions of firms, families, restaurants, mobile facilities, and automobiles, etc. Conventionally, a microwave sulfur lamp works by supplying a raised voltage to a magnetron with an LC transformer operated at the industrial frequency fed from the 220 V power network for producing microwaves to drive the lamp bulb to generate light. A lot of heat is produced in the process due to the low efficiency, 60-70% ordinarily, of an industrial frequency transformer. Besides, the ideal power feeding condition of matched pure direct current with no disturbance for the magnetron is often hardly met by the high voltage commutated current from an industrial frequency transformer, causing a low operational efficiency of the magnetron of about 60 - 70%, thus about 40% of the electricity is dissipated into heat but not transformed as microwave. Such large amount of heat causes a high temperature, over 350° can often be detected at a test point on the magnetron surface, which is close to its critical status and will reduce the lifetime of the magnetron, and damage may be caused even when operated in favorable environment. Conventionally an air blast engine has been included for forced cooling, then there must be air intake and outlet on the out cover of the device, through which large amounts of fast heated smog and salt-fog can be absorbed by the operating microwave sulfur lamp, cutting down the lifespan of the product, and even breaking the device, as a result, it is difficult to apply and popularize such a microwave sulfur lamp. Quite much electricity is wasted because of the low efficiencies of the LC industrial frequency power transformer and of the magnetron, conventional microwave sulfur lamps are now remained in the stage of laboratory research having no prospect for industrial large scale production and application. Moreover, the big size and heavy weight of an industrial frequency transformer result also in the inconvenience for the installation, maintenance, and anti-windage of the product to a great extent.

Summary of the Invention

The object of the present invention is to provide a wholly sealed microwave sulfur lamp, with the advantage of good heat-sinking effect while wholly sealed.

Said object can be realized by means of the following technical solutions:

A wholly sealed microwave sulfur lamp, comprising: a direct current high voltage producing circuit, a magnetron coupled with said direct current high voltage producing circuit for producing a microwave driven by the high voltage direct current, a quartz bulb coupled to the magnetron for containing a luminescent sulfur vapor to be excited by said microwave; the present microwave sulfur lamp is characterized in further comprising an out cover wholly sealed for enclosing said direct current high voltage producing circuit and magnetron with heat-conductive material also enclosed therein. Preferably, said wholly sealed microwave sulfur lamp further comprising a waveguide cavity arranged inside said out cover for coupling said magnetron with the quartz bulb.

Preferably, said wholly sealed microwave sulfur lamp further comprising a co-axial cable for coupling said magnetron with the quartz bulb. Preferably, inside said wholly sealed microwave sulfur lamp, said heat-conductive material is at least one of a metal heat-conductor, a heat- conductive oil, a heat-conductive gel, and a heat-conductive resin.

Preferably, the external surface of the out cover of said wholly sealed microwave sulfur lamp is provided with metal heat radiators.

Preferably, said wholly sealed microwave sulfur lamp further comprising an oil pump provided inside the out cover for promoting heat exchange with a heat-conductive liquid.

Preferably, said wholly sealed microwave sulfur lamp further comprising a high-temperature sealing piece mounted at the anode of the magnetron to prevent the heat-conductive material from leaking via the anode of the magnetron.

In comparison with prior art, the present invention has the following advantageous effects: First, in a conventional microwave sulfur lamp, the magnetron is driven by a raised voltage from an LC industrial frequency transformer connected to the 220 V power supply, and an air blast engine is used for forced wind cooling the direct current high voltage producing circuit and the magnetron, of which the efficiencies are low, thus lots of heat cannot be spread out from the device, the purpose of cooling is hardly attained, causing the lifetime of the magnetron decreased and the efficiency for energy spending low. Such drawbacks have been overcome in the present invention by using an improved magnetron with an electronic frequency conversion power supply, the temperature of the heated magnetron is lowered clearly and their efficiencies are raised appreciably. And an electronic frequency conversion heat radiator is used to lower the temperature of the device to such an extent that heat transfer can be achieved with only the heat-conductive material and without windblast cooling, making this wholly sealed product possible. Moreover, the overall efficiency and lifetime of the lamp are increased greatly.

Secondly, conventionally used industrial frequency high voltage transformer has big size and heavy weight, the present invention makes the overall size and weight of the device much smaller, the cost of the product will also decrease. Because the temperature of the device is much lower, its lifetime increased quite a lot. Since the present device is wholly sealed, its installation becomes more secured. The present product can work normally in adverse circumstances.

Description of the Drawings

Figure 1 is a block diagram for the circuit of a wholly sealed microwave sulfur lamp according to a preferable embodiment of the present invention.

Figure 2 is a sketch view of a wholly sealed microwave sulfur lamp according to a preferable embodiment of the present invention.

Detailed Description of the Embodiments

As shown in the circuit in Fig. 1, electronic frequency conversion power supply 111 and high voltage pack 112 form the major components of the direct current high voltage producing circuit for generating high voltage direct currents, specifically speaking, electricity of 220 V is inputted to electronic frequency conversion power supply 111, for which an LC transformer e.g. may be adopted, to be frequency converted therein, then coupled to high voltage pack 112 for providing more than 1 KV high voltage direct current to magnetron 13, and microwave produced wherefrom is transmitted to the quartz bulb 15 through waveguide cavity 14. In the starting stage, microwave energy is coupled with the starting gas inside bulb 15 to warm up the bulb, the filled vapor is thus excited to generate a continuous spectrum.

Bulb 15 is wrapped up in a mesh like metal shielding mantle 16 to retain microwave leakage. Electric motor 17 is used to rotate quartz bulb 15 for making its lighting and cooling more uniform. High temperature quartz mirror 18 is positioned at the back of bulb 15 to enhance light reflection. Control unit 19 is connected to electronic frequency conversion power supply 111, magnetron 13 and bulb 15 for intelligent detection and failure prevention of these units for securing normal operation and overall reliability. Figure 2 is a sketch view of a wholly sealed microwave sulfur lamp according to a preferable embodiment of the present invention.

As shown in Fig. 2, there disposed inside out cover 2 are magnetron 13, electronic frequency conversion power supply 111, high voltage pack 112, and wave guide cavity 14, and there is heat-conductive material 21, 21a, and 21b (such as a heat-conductive gel, a heat- conductive oil, and a heat-conductive resin etc.) filled inside out cover 2. And disposed outside of out cover 2 are control unit 19, electric motor 17, and oil pump 18, oil pump 18 is connected to the inner side of out cover 2 through a pipe for promoting convection of the heat-conductive material in order to improve heat-sinking effect. Preferably, out cover 2 may be made of metal (such as aluminum alloys), and its external surface is disposed with metal heat radiator 23 as shown in Fig. 2. Preferably, metal heat radiator 23 may adopt a type of groups of heat radiating metal fins.

Bulb 15 wrapped up in a mesh like metal shielding mantle 16 is mounted on the external surface of out cover 2, and the power supply cable 24 is connected to electric motor 17, control unit 19 and oil pump 18 through out cover 2. As shown in Fig. 2, the opening of out cover 2 is covered by lid 31, which is fixed on out cover 2, seal ring 32 is disposed between out cover 2 and lid 31 to isolate the inner part of out cover 2 from outside, and disposed on lid 31 in the manner also shown in Fig. 2 are holder 34, bulb 15, metal shielding mantle 16, reflection shade 18a, mirror 17a, and wave guide cavity 14.

As shown in Fig. 2, magnetron 13 may be fixed on lid 31, in order to seal magnetron 13 tightly within cover 2 to prevent oil leak, anode 13a is necked at its connection with magnetron 13 by high-temperature sealing piece 45 so as to prevent heat-conductive material (such as heat- conductive oil) leakage from anode 13a of magnetron 13.

Here magnetron 13 is dipped in the heat-conductive material filling the inner side of out cover 2, and metal heat radiator 23 is disposed at the outside of out cover 2, therefore, the large amount of heat produced by magnetron 13 will be transferred onto out cover 2 via heat-conductive material 21, and then spread out into the atmosphere through heat radiator 23, in this way, the operational temperature of magnetron 13 is controlled within a normal range. Besides, heat produced by electronic frequency conversion power supply 111 and high voltage pack 112 is also transferred onto out cover 2 via heat- conductive materials 21a and 21b (such as the heat-conductive insulating epoxy resin concreted together with electronic frequency conversion power supply 111 and high voltage pack 112), and then spread out into the atmosphere through heat radiator 23, thus resulting a natural heat dissipation cooling. By means of this structure of sealing magnetron 13, electronic frequency conversion power supply 111 and high voltage pack 112 together within out cover 2, the components such as direct current high voltage circuitry and the magnetron are wholly sealed.

Through the feeding mode of the specialized electronic frequency conversion power supply and the dedicated direct current high voltage pack, the magnetron is driven to produce microwaves. According to the present invention, this electronic frequency conversion power supply can resist the interference of magnetic radiation and the disturbance from the single chip processor by special means, such as a robust protection circuit and a zero-potential twin transistor IGBT driving mode, such specialized electronic frequency conversion power supply has a much higher operating efficiency of more than 90%, and this unique magnetron high voltage direct current power feeding mode via dedicated high voltage pack has raised magnetron efficiency from 60- 70% up to more than 80%.

In said wholly sealed microwave sulfur lamp, the temperature of the magnetron and the working temperature of the heat radiator of the electronic frequency conversion power supply are lowered from conventional 150⁰C to the present only about 80⁰C by means of conduction of heat-conductive dielectric material plus pumped oil flow, thus the temperature of the magnetron and the working temperature of the heat radiator of the electronic frequency conversion power supply are kept within normal 8O⁰C, and the lifetime of the magnetron and reliability of the device are increased apparently. The present solution may easily adopt conduction of heat-conductive material for heat spreading via out cover, thus conventional wind blasting cooling is never needed here.

In said wholly sealed microwave sulfur lamp, a wholly sealed structure has been realized through manufacture process, such wholly sealed structure has achieved a product of smaller size, lighter weight, and lower cost. The installation and maintenance of such a device become more convenient and reliable, it can thus work normally under various unfavorable circumstances.

In said wholly sealed microwave sulfur lamp, the electronic frequency conversion power supply may be sealed as a module by using special magnetic radiation isolating material to keep single chip microprocessor from radiation disturbance, so that the single chip microprocessor can operate constantly at IGBT in a pure modulation wave dual-driving zero-potential mode, resulting in a power supply efficiency higher than 90%. In this way, heat from the power supply heat radiator can be brought out via oil flow and conduction, guaranteeing overall operation under normal temperature.

It is obvious for the technical personnel in this field, who have read what are disclosed here, to make any modifications. Such modifications may relate to technical features commonly known to the technical personnel in this and its adjacent fields, and such features may be utilized as a substitute and/or addition to what have been described above.

Claims

1. A wholly sealed microwave sulfur lamp, comprising: a direct current high voltage producing circuit, a magnetron coupled with said direct current high voltage producing circuit for producing a microwave driven by the high voltage direct current, a quartz bulb coupled to the magnetron for containing a luminescent sulfur vapor to be excited by said microwave; which is characterized in further comprising: an out cover wholly sealed for enclosing: said direct current high voltage producing circuit, magnetron, and heat-conductive material.

2. The wholly sealed microwave sulfur lamp as claimed in Claim 1, further comprising a waveguide cavity arranged inside said out cover for coupling said magnetron with the quartz bulb.

3. The wholly sealed microwave sulfur lamp as claimed in Claim 1, further comprising a co-axial cable for coupling said magnetron with the quartz bulb.

4. The wholly sealed microwave sulfur lamp as claimed in Claim 1, wherein said heat-conductive material is at least one of a heat- conductive oil, a heat-conductive gel, and a heat-conductive resin.

5. The wholly sealed microwave sulfur lamp as claimed in Claim 1, wherein the external surface of said out cover is provided with metal heat radiators.

6. The wholly sealed microwave sulfur lamp as claimed in Claim 1, further comprising an oil pump provided outside the out cover for promoting heat exchange with a heat-conductive material.

7. The wholly sealed microwave sulfur lamp as claimed in Claim 1, further comprising a high-temperature sealing piece mounted at the anode of said magnetron to prevent the heat-conductive material from leaking via the anode of the magnetron.