FIELD OF THE INVENTION

The present invention relates to an improved complex evaporator and pressure regulator for a low temperature bio oxygen demand incubator or a low temperature testing equipment.

BACKGROUND OF THE INVENTION

Low temperature bio oxygen demand incubator mainly consist of a main insulated exterior shell having a storage chamber for storing of biological samples and specimens, a refrigerating system, a heating element and temperature control system. Since biological specimens are stored in the incubator, a constant low temperature is required to be maintained in the said incubator. Due to the low temperature, over time, frosting will take place on the surface of the complex evaporator.

For long term efficient running of the incubator, both refrigerating system and heating element should be working continuously and balanced by a temperature control system. Inspite of the balancing, frost will be produced on the surface of complex evaporator generally. The frost will therefore affect the efficiency of the refrigerating system and the incubator would not be able to continue normal operations.

Currently, defrosting is by hand regularly or by automatic heating. However, for long- term operation, repeat defrosting is needed. Both hand-defrosting and automatic heating will cause temperature in the inner chamber to be unstable. This temperature fluctuation will affect testing process and results. Moreover, defrosting by heating needs heat energy and power consumption by the equipment is therefore increased

Over a long period of operation of the incubator, as frosting continues, the incubator may have to undergo a defrosting cycle in order to remove the frost. Should there be temperature fluctuation, as a precaution, the biological samples and specimens have to be transferred to another incubator for temporary safekeeping. Once the original incubator is defrosted, the biological samples and specimens are then transferred back to the defrosted incubator.

It is desirable that a low temperature testing equipment has high accuracy and consistency in maintaining the biological samples and specimens at a required temperature and small temperature fluctuation during long-term running in a laboratory.

SUMMARY OF THE PRESENT INVENTION

An Improved refrigerating system and controlling system is proposed to overcome the disadvantages of current low temperature testing equipment. The improvements are inclusion of a pressure regulator and a complex evaporator in the refrigerating system.

1. Pressure regulator

There are 2 pieces copper rods coiled within a sealed cylinder container. During normal operation, a first copper rod is the main rod for throttling therefore complete refrigerating process. As defrosting takes place, the control system directs an electric-magnetic valve which controls the opening and closing of a second copper rod therefore the low pressure of the recycling system is adjusted. Pressure of evaporation and evaporating temperature is then changed. Defrosting is achieved. Temperature fluctuation is reduced in the meantime.

2. Complex evaporator

9.6mm long copper coil is coiled to form 6 multi-loops (One coil is one loop). These coils are closely laid and pressed parallel to the radiation fin on the copper coil, layer by layer. Therefore a complex evaporator with radiation fin is formed. 2 holes in two of the copper coils on both sides at the middle of the complex evaporator is reserved for insertion of a heating element of 8 mm diameter.

The heating element is inserted into the complex evaporator. Heat and cold can therefore be balanced but this arrangement also delays the frosting cycle on the surface of complex evaporator as heat energy is transmitted from inside to outside of heating element.

During defrosting, heating element works as normal without any other heat energy involved.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention described and claimed herein may be better understood with reference to the accompanying drawings, which depict a preferred embodiment of the invention and which are intended merely to illustrate rather than limit the invention in scope.

Fig. 1 is a view from the side with cut through view of an improved low temperature testing equipment (1) with the invention.

Fig. 2 is a perspective view from the back of the improved low temperature testing equipment (1 ).

Fig. 3 is a perspective view of the front and side of the improved low temperature testing equipment (1) showing the inventive features of the present invention.

Fig. 4 is a cut through view from the side of the improved low temperature testing equipment (1) showing the inventive features of the present invention.

Fig. 5 is an illustration of the complex evaporator (18).

Fig. 6 is a side view of the complex evaporator (18).

Fig. 7 is a top view of the complex evaporator (18).

Fig. 8 is a view of the pressure regulator (16).

Fig. 9 is a view of the cross section view of the pressure regulator (16) showing the internal parts. DETAILED DESCRIPTION OF THE INVENTION

Detailed embodiment of the present invention is disclosed herein. However, it is to be understood that the disclosed embodiment is merely exemplary of the present invention which may be embodied in various systems. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of skill in the art to variously practice the invention.

A pressure regulator (16) and a complex evaporator (18) which are the inventive features are incorporated into the refrigerating system (12) for an improved low temperature testing equipment (1 ). The pressure regulator (16) and complex evaporator (18) would enable the refrigerating system (12) and temperature control system (14) to efficiently manage the improved low temperature testing equipment (1 ) and overcome the disadvantages of current improved low temperature testing equipment (1).

Fig. 1 is a view from the side with cut through view of an improved low temperature testing equipment (1 ) with the invention.

Fig. 2 is a perspective view from the back of the improved low temperature testing equipment (1 ).

Fig. 3 is a perspective view of the front and side of the improved low temperature testing equipment (1 ) showing the inventive features of the present invention.

Fig. 4 is a cut through view from the side of the improved low temperature testing equipment (1 ) showing the inventive features of the present invention.

The operations of an improved low temperature testing equipment (1 ) will be discussed briefly herein by reference to Fig. 1 , Fig. 2, Fig. 3 and Fig. 4.

The improved low temperature testing equipment (1 ) consist of a main insulated exterior shell having a storage chamber (10) for storing of biological samples and specimens, a refrigerating system (12), a heating element (20) and a temperature control system (14). The refrigerating system (12) is placed at the back of the improved low temperature testing equipment (1). A door at the front of the improved low temperature testing equipment (1 ) allows biological samples and specimens to be placed in the storage chamber (10) and to be removed, as necessary. Since biological samples and specimens are stored, the storage chamber (10) has to be maintained at a consistent low temperature required for the viability of these samples and specimens. Due to the low temperature, over time, frosting will take place on the surface of the complex evaporator (18).

The workings of the refrigerating system (12) is known art and will be briefly discussed for the purpose of referring to it when describing how the improved low temperature testing equipment (1 ) works. The refrigerating system (12) has a compressor which compresses the refrigerant gas. This raises the refrigerant's pressure and temperature, and the heat-exchanging coils of the refrigerating system (12) allows the refrigerant to dissipate the heat of pressurization. As the refrigerant cools, it condenses into a liquid and flows through the expansion valve, moving from a high pressure zone to a low pressure zone, expanding in the process, absorbing heat, making it cold. The coils of the refrigerating system (12) allows the refrigerant to absorb heat, reducing the temperature within the storage chamber (10).

For long term efficient running of the improved low temperature testing equipment (1), both refrigerating system (12) and the heating element (20) should be working continuously and both heat and cold will be balanced by the temperature control system (14). Inspite of the balancing, frost will be produced on the surface of evaporator generally. The frost will therefore affect the efficiency of the refrigerating system (12) and the complex evaporator (18) of the improved low temperature testing equipment (1 ) would have to undergo defrosting. Defrosting is usually carried out manually on a regular basis or done by automatic heating. However, for long-term operations, repeated defrosting is needed. Both manual defrosting and automatic heating will cause temperature fluctuation in the storage chamber (10) affecting the biological specimens and samples. In turn, this temperature fluctuation will affect testing process and results. Moreover, defrosting by heating needs heat energy, power consumption by the equipment is therefore increased

Sometimes there is a need for a longer period of defrosting. As a precaution, the biological samples and specimens have to be transferred to another improved low temperature testing equipment (1) for temporary safekeeping. Once the original incubator is defrosted, the biological samples and specimens are then transferred back to the defrosted incubator. This step invariably affects laboratory procedures and is not recommended.

A description of the complex evaporator (18) is now given with reference to Fig. 5, Fig. 6 and Fig. 7. Fig. 5 is an illustration of the complex evaporator (18). Fig. 6 is a side view of the complex evaporator (18). Fig. 7 is a top view of the complex evaporator (18).

Complex evaporator (18)

9.6mm long copper coil (22) is coiled to form 6 multi-loops (One coil is one loop). The coils are closely packed and pressed as parallel radiation fin on the copper coil (22) layer by layer. The complex evaporator (18) with radiation fin is thus formed. 2 holes are reserved for 2 pieces of copper coil (22) on both sides at the middle of the complex evaporator (18) for insert 8mm diameter heating element (20). The heating element (20) is inserted into the complex evaporator (18). Heat and cold can therefore be balanced but also delays the frosting cycle on the surface of complex evaporator (18) as heat energy is transmitted from inside to outside of heating element (20).

During defrosting, the heating element (20) works as normal without any other heat energy involved.

By balancing the cold source and heat source, highly accurate and constant temperature can be prolonged. The heating element (20) inserted in the evaporator's copper coil (22) can help to balance cold and heat within the low temperature testing equipment (1 ) by transferring the heat to the radiation fins.

The workings of the pressure regulator (16) will be described with reference to Fig. 8 and Fig. 9. Fig. 8 is a view of the pressure regulator (16). Fig. 9 is a view of the cross section view of the pressure regulator (16) showing the internal parts. Pressure regulator (16)

It consists of a first copper rod (30) and a second copper rod (32), both rods coiled within a sealed cylinder container (36). An electric-magnetic valve (34) controls the opening and closing of the second copper rod (32) resulting in low pressure of the refrigerating system (12). Pressure of evaporation and evaporating temperature is then changed, causing defrosting with minimal temperature fluctuation in the meantime.

The object of the pressure regulator (16) is control or regulation of pressure of the refrigerant, to reduce the temperature variation in the process of frosting. When the refrigeration system (12) requires defrosting, low pressure will be changed by adjusting the amount of refrigerant therefore evaporating temperature is changed. Defrosting process is completed. The pressure regulator (16) minimizes the influence on temperature variation during defrosting and reduces use of heat energy.

During normal operation, the first copper rod (30) acts to throttle the pressure, therefore it acts to complete refrigerating process. As defrosting takes place, the temperature control system (14) directs an electric-magnetic valve (34) which controls opening and closing of the other second copper rod (32). Low pressure of the recycling system is adjusted. Pressure of evaporation and evaporating temperature is changed. Defrosting is achieved. Temperature fluctuation is reduced in the mean time.

EFFICIENCY WITH IMPROVEMENTS

The complex evaporator help prolong the frosting cycle on its surface under normal condition therefore the complex evaporator (18) is able to work over a longer period of time.

During defrosting, the control system controls electric-magnetic valves (34) therefore adjust low pressure of the recycling system. As a result, it changes pressure of evaporation and evaporating temperature.

Meanwhile, power of heating is reduced rapidly according to reduction of the refrigerating for balancing cold and heat. This would ensure temperature within low temperature testing equipment (1) is stable. Moreover, the defrosting time will be reduced from 30 min to around 10 min.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

ADVANTAGEOUS EFFECTS OF THE INVENTION

The invention overcomes the current periodic procedure of defrosting faced in operating low temperature testing equipment (1) in laboratories using either manual defrosting or by automatic heating. Current procedures of manual defrosting and automatic heating will affect biological samples and specimens due to fluctuation in temperature in the storage chamber (10). Such temperature fluctuations will affect testing process and results. Moreover, defrosting by heating needs heat energy, power consumption by the equipment is therefore increased

The improved low temperature testing equipment (1 ) ensures biological samples and specimens are kept at a required temperature with consistency and accurately, reducing maintenance costs and energy costs.