Silicone oil circulating system for vacuum freeze dryer

Abstract

The utility model discloses a silicone oil circulating system for a vacuum freeze dryer, which belongs to the field of freeze dryer operation monitoring and comprises a circulating pump, a heater, a refrigeration heat exchanger and a differential pressure protector, and an inlet and an outlet of the circulating pump are both connected to the differential pressure protector. The pressure difference protector is introduced into the silicone oil circulating system, and the inlet and the outlet of the circulating pump are connected to the pressure difference protector, so that a stable pressure difference can be maintained in the circulating process. And the working pressure at the inlet end and the outlet end of the circulating pump can be monitored, and the abnormal condition of silicone oil circulation caused by oil shortage or blockage can be accurately judged through the comparison of the pressure difference.

Description

Technical Field

[0001] This utility model belongs to the field of freeze dryer operation monitoring, specifically, it relates to a silicone oil circulation system for a vacuum freeze dryer. Background Technology

[0002] A freeze dryer involves freezing and vacuuming materials to be dried. Through a refrigeration and vacuum system, the material is frozen and depressurized, causing the moisture in the material to sublimate into water vapor and escape, resulting in a dried material. Freeze dryers are widely used in food, biological products, and pharmaceuticals, where strict requirements on product form and moisture content are necessary. The silicone oil circulation system, a crucial component of a freeze dryer, seals the vacuum valves within the freeze dryer chamber and acts as a condenser to condense the vapor generated during vacuuming. Existing silicone oil circulation systems primarily consist of a circulation pump, a heater, and a refrigeration heat exchanger. The circulation pump circulates the silicone oil, while the heater and heat exchanger heat and cool the silicone oil, respectively. The heater transfers heat to the silicone oil via an electric heating element; the heat exchanger, through the compressor, condenser, expansion valve, and evaporator in the refrigeration unit, changes the temperature of the silicone oil. Throughout this process, the silicone oil, driven by the circulation pump, sequentially passes through the heater and heat exchanger.

[0003] In actual production, the silicone oil circulation system needs to operate continuously. Existing silicone oil circulation systems are prone to damage after long-term operation. Therefore, a detection system is set up for the freeze dryer. For example, Chinese patent CN215676086U discloses a freeze dryer heat exchange system, including a freeze dryer plate, a circulation pump, a heater, a heat exchanger, and at least one refrigeration unit. The freeze dryer plate, circulation pump, heater, and heat exchanger are sequentially connected to form a loop. The second channel of the heat exchanger is also connected to the refrigeration unit. The system also includes a control module. A first temperature sensor is installed at the inlet of the freeze dryer plate, and a second temperature sensor is installed at the outlet of the second channel of the heat exchanger. The input terminal of the control module is connected to the first and second temperature sensors, respectively, and the output terminal of the control module is connected to the control terminals of the heater and the refrigeration unit, respectively, so that the control module can obtain the temperature feedback of the heat transfer medium in the second channel of the heat exchanger from the temperature detection value of the second temperature sensor. However, existing technologies generally only install pressure switches at the outlet of the circulating pump, and there is no pressure monitoring at the inlet of the circulating pump. When the circulating pump is blocked, both the outlet and inlet pressures are high. At this time, the silicone oil cannot circulate normally, and this fault cannot be detected by only protecting it with the outlet pressure switch.

[0004] In view of the above, this application is hereby submitted. Utility Model Content

[0005] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a silicone oil circulation system for a vacuum freeze dryer. This invention is achieved through the following technical solution:

[0006] A silicone oil circulation system for a vacuum freeze dryer includes a circulation pump, a heater, and a refrigeration heat exchanger, and also includes a differential pressure protector, wherein the inlet and outlet of the circulation pump are both connected to the differential pressure protector.

[0007] Preferably, a voltage protector and a current overload protector are connected in series on the power supply line of the circulating pump.

[0008] Preferably, an external over-temperature protection switch is provided on the outside of the heater, and an internal overheat protection switch is provided inside the heater.

[0009] Preferably, the power supply line of the heater is equipped with a power supply overcurrent protector.

[0010] Preferably, the outlet of the refrigeration heat exchanger is equipped with a silicone oil temperature probe.

[0011] Preferably, the pipelines at both ends of the differential pressure protector are connected to the inlet and outlet of the circulating pump through valve bodies.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. By introducing a differential pressure protector into the silicone oil circulation system and connecting the inlet and outlet of the circulation pump to this protector, a stable differential pressure can be maintained during circulation. The operating pressures at both the inlet and outlet of the circulation pump can also be monitored, and by comparing the differential pressures, it is possible to accurately determine whether the abnormal silicone oil circulation is caused by insufficient oil or blockage.

[0014] 2. By connecting a voltage protector and a current overload protector in series on the power supply line of the circulating pump, motor damage caused by abnormal voltage or excessive current can be effectively avoided, thereby enhancing the stability and durability of the system and reducing maintenance costs and the risk of unexpected downtime.

[0015] 3. With the dual protection mechanism of external over-temperature protection switch and internal overheat protection switch of the heater, the power supply can be automatically cut off when the temperature exceeds the set safety range, preventing the heating element from failing due to overheating or causing safety accidents, ensuring the safety of operators and improving the safety factor of the equipment. Attached Figure Description

[0016] Figure 1 This is a system schematic diagram of this utility model.

[0017] In the diagram: 1. Freeze dryer; 2. Plate layer; 3. Circulating pump; 31. Voltage protector; 32. Current overload protector; 33. Differential pressure protector; 4. Heater; 41. External over-temperature protection switch; 42. Internal overheat protection switch; 43. Power supply overcurrent protector; 5. Refrigeration heat exchanger; 51. Silicone oil temperature probe. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] like Figure 1 As shown, this embodiment provides a silicone oil circulation system for a vacuum freeze dryer. The freeze dryer 1 contains a plate. The silicone oil circulation system of the freeze dryer 1 includes a circulation pump 3, a heater 4, and a refrigeration heat exchanger 5. It also includes a differential pressure protector 33. The inlet and outlet of the circulation pump 3 are both connected to the differential pressure protector 33.

[0020] By introducing a differential pressure protector 33 into the silicone oil circulation system and connecting the inlet and outlet of the circulation pump 3 to this protector, a stable differential pressure can be maintained during circulation. The operating pressures at the inlet and outlet of the circulation pump 3 can also be monitored, and by comparing the differential pressures, it can be accurately determined whether the abnormal silicone oil circulation is caused by insufficient oil or blockage.

[0021] Furthermore, a voltage protector 31 and a current overload protector 32 are connected in series on the power supply line of the circulating pump 3.

[0022] By connecting a voltage protector 31 and a current overload protector 32 in series on the power supply line of the circulating pump 3, motor damage caused by abnormal voltage or excessive current can be effectively avoided, thereby enhancing the stability and durability of the system and reducing maintenance costs and the risk of unexpected shutdown.

[0023] Furthermore, an external overheat protection switch 41 is provided on the outside of the heater 4, and an internal overheat protection switch 42 is provided inside the heater 4.

[0024] With the dual protection mechanism of the heater 4's external over-temperature protection switch 41 and internal overheat protection switch 42, the power supply can be automatically cut off when the temperature exceeds the set safe range, preventing the heating element from failing due to overheating or causing safety accidents, ensuring the safety of operators and improving the safety factor of the equipment.

[0025] Furthermore, an overcurrent protector 43 is installed on the power supply line of the heater 4. This overcurrent protector 43 allows for a rapid response when excessive current occurs in the circuit, protecting the heater 4 from potential damage. This not only helps ensure the safe and controllable heating process but also further improves the safety and reliability of the entire system.

[0026] A silicone oil temperature probe 51 is installed at the outlet of the refrigeration heat exchanger 5. Installing the silicone oil temperature probe 51 at the outlet of the refrigeration heat exchanger 5 allows the system to monitor the temperature changes of the silicone oil in real time and adjust the refrigeration capacity accordingly to maintain optimal operating conditions. This feedback control mechanism improves freeze-drying efficiency while ensuring the consistency and stability of product quality.

[0027] Preferably, the pipelines at both ends of the differential pressure protector 33 are connected to the inlet and outlet of the circulating pump 3 via valve bodies. Connecting the pipelines at both ends of the differential pressure protector 33 to the inlet and outlet of the circulating pump 3 via valve bodies allows the system to respond more flexibly to the needs of different operating conditions, facilitates the adjustment and optimization of the detection status through the valve body, and thus improves the system's operating efficiency and adaptability. In addition, adding valve bodies also facilitates system maintenance and repair.

[0028] Specifically, the voltage protector 31 for powering the circulating pump 3 is connected in series on the three-phase power supply line of the circulating pump 3. When the power supply voltage of the circulating pump 3 is greater than 110% of the rated value or less than 90%, the voltage protector 31 will output an alarm signal to indicate that the power supply voltage of the circulating pump 3 is faulty.

[0029] The overload protector 32 of the circulating pump 3 is connected in series in the power supply circuit between the voltage protector 31 and the silicone oil circulating pump 3. When the operating current of the circulating pump 3 exceeds 120% of the rated value, the overload protector 32 will output an alarm signal and cut off the power supply to the circulating pump 3, indicating that the circulating pump 3 has an overload fault.

[0030] The two ends of the differential pressure protector 33 are connected to the inlet and outlet of the circulating pump 3 through the valve body. When the pressure difference between the inlet and outlet of the circulating pump 3 is less than 80% of the rated value, the differential pressure protector 33 will output an alarm signal, indicating that the circulating pump 3 may be working under abnormal pressure due to lack of oil or blockage.

[0031] The temperature sensor of the external over-temperature protection switch 41 of the heater 4 is fixed to the outer surface of the silicone oil heater 4 using a stainless steel strip. The outer surface of the temperature sensor of the over-temperature protection switch is covered with rubber and plastic insulation material to reduce the influence of ambient temperature. When the outer surface temperature of the silicone oil heater 4 exceeds 80°C, the external over-temperature protection switch 41 will output an alarm signal and cut off the power supply to the heater 4, indicating that the outer surface temperature of the heater 4 is too high.

[0032] The temperature sensor of the internal overheat protection switch 42 of the heater 4 is inserted into the internal blind tube port of the silicone oil heater 4 (not shown in the figure) through a blind tube, and the blind tube port is covered with rubber and plastic material. When the internal temperature of the silicone oil heater 4 exceeds 80°C, the internal overheat protection switch 42 will output an alarm signal and cut off the power supply to the heater 4, indicating that the internal temperature of the heater 4 is overheated.

[0033] The power supply overcurrent protector 43 of heater 4 is connected in series on the three-phase power supply line of the silicone oil heater 4. When the operating current of heater 4 is greater than 120% of the rated value, the power supply overcurrent protector 43 will output an alarm signal and cut off the power supply to heater 4, indicating that the operating current of heater 4 is abnormal.

[0034] The silicone oil temperature probe 51 at the outlet of the refrigeration heat exchanger 5 is inserted into the silicone oil outlet pipe of the refrigeration heat exchanger 5 through a blind tube filled with silicone oil to assist heat conduction. When the silicone oil temperature probe 51 at the outlet of the refrigeration heat exchanger 5 detects a temperature below -60℃, it will indicate that the temperature of the refrigeration heat exchanger 5 is too low and stop working.

Claims

1. A silicone oil circulation system for a vacuum freeze-dryer comprising a circulation pump (3), a heater (4) and a refrigeration heat exchanger (5), characterised in that: A differential pressure protector (33) is further included, and the inlet and outlet of the circulating pump (3) are connected to the differential pressure protector (33).

2. A silicone oil circulation system for a vacuum freeze dryer as defined in claim 1, wherein: A voltage protector (31) and a current overload protector (32) are connected in series on the power supply line of the circulating pump (3).

3. A silicone oil circulation system for a vacuum freeze dryer as defined in claim 1, wherein: An external over-temperature protection switch (41) is arranged outside the heater (4), and an internal over-temperature protection switch (42) is arranged inside the heater (4).

4. A silicone oil circulation system for a vacuum freeze dryer as defined in claim 3, wherein: A power supply over-current protector (43) is arranged on the power supply line of the heater (4).

5. A silicone oil circulation system for a vacuum freeze dryer as defined in claim 1, wherein: A silicon oil temperature probe (51) is arranged at the outlet of the refrigeration heat exchanger (5).

6. A silicone oil circulation system for a vacuum freeze dryer as defined in claim 1, wherein: The pipelines at both ends of the differential pressure protector (33) are connected to the inlet and outlet of the circulating pump (3) through valve bodies.

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