Fan assembly, patient ventilation system, and MRI system

Abstract

The utility model discloses a fan assembly, patient ventilation system and magnetic resonance imaging system for patient ventilation system in magnetic resonance imaging system, wherein, fan assembly includes: fan group, it includes at least two axial flow fan, at least two axial flow fan is fixed with the way of realizing air port series pressurization, magnetic shielding casing, it covers the periphery of fan group, air inlet connector, it is arranged on the air inlet side of magnetic shielding casing near fan group for with the air inlet pipeline connection of patient ventilation system, and air outlet connector, it is arranged on the air outlet side of magnetic shielding casing near fan group for with the patient ventilation pipeline connection of patient ventilation system. The technical scheme in the utility model embodiment can solve the patient ventilation problem of MRI system.

Description

Technical Field

[0001] This utility model relates to the field of magnet cooling technology, and in particular to a fan assembly for a patient ventilation system in a magnetic resonance imaging system, a patient ventilation system, and a magnetic resonance imaging system. Background Technology

[0002] Magnetic Resonance Imaging (MRI) systems utilize the magnetic field generated by magnets to obtain information about molecular structure and internal structure of the human body through the nuclear magnetic resonance phenomenon.

[0003] During MRI scans, to ensure patient comfort and limit temperature rise due to radiofrequency energy absorption rate (SAR), a patient ventilation system is required within the MRI system to provide airflow near the patient. The patient ventilation system typically includes: an air inlet, an air inlet duct, a patient fan, a patient ventilation duct, and a patient vent. The air inlet is usually located on the rear cover of the MRI system housing, near the floor, and typically has an air filter. The air inlet duct connects the air inlet and the patient fan, delivering air from the air inlet to the patient fan. The patient fan generates the air pressure that causes airflow from the air inlet to the patient vent. The patient ventilation duct connects the patient fan and the patient vent, delivering air from the patient fan to the patient vent. The patient vent is typically located on the flared housing where the patient enters and exits the MRI scanning space, providing airflow near the patient.

[0004] In particular, considering the presence of magnetic fields in the MRI system, the specific settings of the patient fan should take into account issues such as magnetic field interference.

[0005] Therefore, those skilled in the art have been working to find better patient ventilation system solutions for MRI systems. Utility Model Content

[0006] In view of this, this application provides, on the one hand, a fan assembly for a patient ventilation system in a magnetic resonance imaging system, and on the other hand, a patient ventilation system and a magnetic resonance imaging system, to solve the patient ventilation problem of MRI systems.

[0007] This application proposes a fan assembly for a patient ventilation system in a magnetic resonance imaging system, comprising: a fan unit including at least two axial flow fans, the at least two axial flow fans being fixedly arranged to achieve series pressurization of the air outlets; a magnetic shielding housing covering the periphery of the fan unit; an air inlet connector disposed on the magnetic shielding housing near the air inlet of the fan unit for connecting to the air inlet duct of the patient ventilation system; and an air outlet connector disposed on the magnetic shielding housing near the air outlet of the fan unit for connecting to the patient ventilation duct of the patient ventilation system.

[0008] In one embodiment, the fan assembly further includes: a fan mounting bracket for fixing the at least two axial flow fans.

[0009] This application proposes a patient ventilation system for an MRI system, comprising: an air inlet, an air inlet duct, a patient ventilation duct, and a patient ventilation outlet; the patient ventilation system further comprises: the aforementioned fan assembly for a patient ventilation system in an MRI system; and a control unit, which includes a PWM signal generation circuit and a high-frequency filtering circuit; the PWM signal generation circuit is used to generate a PWM control signal for controlling the speed of the fan assembly; the high-frequency filtering circuit is used to filter out high-order harmonics in the PWM control signal.

[0010] In one embodiment, the air velocity at the patient ventilation opening is maintained between 1 and 3 m / s.

[0011] In one embodiment, the fan unit has a pressure of 450-500 Pa.

[0012] The magnetic resonance imaging system proposed in this application includes: the fan assembly of the patient ventilation system in the MRI system described above, or the patient ventilation system in the MRI system described above.

[0013] As can be seen from the above solutions, in this embodiment, at least two axial flow fans are used instead of dedicated centrifugal fans to achieve high-pressure airflow to meet the patient's comfort requirements, and a shielding cover is used to solve the interference problem related to the PWM signal of the axial flow fans. This allows common PWM-controlled axial flow fans to be successfully applied to MRI systems. Because axial flow fans are small and low-cost, they not only meet the application requirements of compact MRI systems, making the placement of patient fans in compact MRI systems more flexible, but also significantly reduce costs. Furthermore, the smaller size of the patient fans provides more space for cables, pipes, or other components, improving system maintainability. Attached Figure Description

[0014] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can more clearly understand the above and other features and advantages of the present invention, in which:

[0015] Figure 1 This is an exemplary structural diagram of a patient ventilation system in one embodiment of the present invention.

[0016] Figure 2 for Figure 1 An exemplary structural diagram of the fan assembly in the patient ventilation system is shown.

[0017] The reference numerals in the attached figures are as follows:

[0018] label meaning 1 air intake 2 intake pipe 3 Patient ventilation duct 4 Patient ventilation opening 5 wind turbine components 51 wind turbine 511 Axial flow fan 52 Magnetic shielding housing 53 Inlet connector 54 Air outlet connector 6 Control Unit 61 PWM signal generation circuit 62 High frequency filter circuit Detailed Implementation

[0019] The inventors of this application have discovered the following problems with the fan setup in the patient ventilation system of an MRI system:

[0020] 1) The patient fan must be able to operate within the magnetic field of an MR (Magnetic Resonance Imaging) system. When the patient fan is placed in a high magnetic field, it will generate low-frequency noise, vibration, heat, or stop rotating. Therefore, the fan should typically be placed outside the magnetic field line of less than 50 mT, and the fan shaft should be parallel to the direction of the magnetic field. This means the fan needs to be far from the patient, requiring a long ventilation duct between the fan and the patient. This, in turn, results in high air resistance, reducing the airflow delivered to the patient.

[0021] 2) The speed of a conventional ventilation fan is controlled by a PWM signal. However, a direct PWM signal from the control unit to the fan can cause radio frequency noise problems in the scanning room. To reduce interference, the control signal for the patient fan in the current MRI ventilation system uses a specially designed DC voltage control signal. Furthermore, to further reduce electromagnetic interference, the patient fan is specially designed with fewer ferromagnetic parts, but this type of fan is relatively expensive, for example, approximately 1750 RMB.

[0022] 3) Based on the high air resistance issue mentioned in 1), in order to provide a comfortable airflow for patients, the aforementioned dedicated patient fan usually uses a centrifugal fan with a size of Ø205*206mm. The size is relatively large. Since it must be placed in the direction mentioned in 1), the overall size of the MRI system will increase. However, smaller MRI systems are the market trend.

[0023] Based on the above problems, in order to solve the high cost and large size issues mentioned in problems 2) and 3), and to reduce the cost and size of the blower, the inventors of this application considered to find a breakthrough in small-sized and low-cost ordinary blowers. After creative work and multiple practices, the inventors of this application discovered that: currently, a single ordinary blower usually cannot provide an airflow that meets the patient's comfort requirements after passing through a long air duct. However, by using more than one ordinary blower, such as an axial flow blower, and installing them in series, the air pressure will increase exponentially with the increase in the number of blowers under the condition of a certain airflow. Therefore, by using at least two axial flow blowers installed in series, the problem of high air resistance mentioned in problem 1) can be solved, that is, an airflow that meets the patient's comfort requirements can be provided.

[0024] Furthermore, to address the radio frequency interference issue of the PWM signal mentioned in problem 2) above, this embodiment considers introducing a high-level filter circuit into the PWM generation circuit. This filter circuit can eliminate high-order harmonics generated by the PWM signal by reducing its slew rate. Moreover, considering that the frequency of the PWM signal is much lower than the critical frequency of MRI, typically below 1MHz, a shield can be further provided for the series-installed fan units. In this way, by setting an appropriate filter circuit and good shielding, the potential noise problem of the PWM signal can be eliminated.

[0025] To provide a clearer understanding of the purpose, technical solution, and effects of this utility model, the specific embodiments of this utility model are now described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate components with the same or similar structures but the same function.

[0026] In this document, “exemplary” and “illustrative” mean “serving as an example, illustration or description”, and any illustration or implementation described herein as “exemplary” or “illustrative” should not be construed as a more preferred or more advantageous technical solution.

[0027] To keep the drawings simple, each drawing only schematically shows the parts related to this utility model, and they do not represent the actual structure of the product.

[0028] In this text, "a" can mean not only "only one" but also "more than one". In this text, "first", "second", etc., are used only to distinguish them from each other, not to indicate their degree of importance or order. "Including" means "including but not limited to", and "according to..." means "at least according to..., but not limited to only according to...".

[0029] Figure 1 This is an exemplary structural diagram of a patient ventilation system for a magnetic resonance imaging system in one embodiment of this application. Figure 2 for Figure 1This is an exemplary structural diagram of the fan assembly in a patient ventilation system. Figure 1 As shown, the system includes: air inlet 1, air inlet pipe 2, patient ventilation pipe 3, patient ventilation outlet 4, fan assembly 5, and control unit 6.

[0030] The air inlet 1 is usually equipped with a filter component such as an air filter cover.

[0031] The air intake pipe 2 is connected between the air intake port 1 and the fan assembly 5, and is used to deliver air from the air intake port to the fan assembly 5.

[0032] The patient ventilation duct 3 is connected between the fan assembly 5 and the patient ventilation port 4, and is used to deliver air from the fan assembly 5 to the patient ventilation port.

[0033] Patient ventilation port 4 is used to deliver airflow to the patient near the patient.

[0034] like Figure 2 As shown, the fan assembly 5 includes: a fan unit 51, a magnetic shielding housing 52, an air inlet connector 53, and an air outlet connector 54.

[0035] The fan unit 51 includes at least two axial flow fans 511, which are fixedly arranged to achieve series pressurization of the air outlets. In practical applications, the at least two axial flow fans 511 can be fixedly installed on a fan mounting bracket ( Figure 1 (Not shown in the image). By connecting at least two identical axial flow fans 511 in series, a large air volume and high pressure can be provided to meet the air volume requirements of the MRI system.

[0036] In one embodiment, the air velocity near the patient in the patient ventilation system can be maintained between 1 and 3 m / s, that is, the air velocity at the patient ventilation opening can be maintained between 1 and 3 m / s. In one embodiment, the patient ventilation system of the MRI system can provide a flow rate of approximately 50 cubic meters per hour. In one embodiment, considering that the ventilation direction of the patient ventilation duct may change relative to the ventilation direction of the inlet duct, the fan unit 51 requires a pressure of approximately 460 Pa, for example, providing an air pressure greater than or equal to 460 Pa.

[0037] The magnetic shielding housing 52 is installed around the fan unit 51 to shield the electromagnetic interference of the magnet in the MRI system to the fan unit 51, as well as the radio frequency noise interference of the PWM control signal of the fan unit 51 to the magnet.

[0038] An air inlet connector 53 is disposed on the magnetic shielding housing 52 near the air inlet side of the fan unit 51, and is used to connect to the air inlet pipe 2.

[0039] An air outlet connector 54 is disposed on the side of the magnetic shielding housing 52 near the air outlet of the fan unit 1, and is used to connect to the patient ventilation duct 3.

[0040] The control unit 6 includes a PWM signal generation circuit 61 and a high-frequency filtering circuit 62.

[0041] The PWM signal generation circuit 61 is used to generate a PWM control signal to control the speed of the fan unit 51. By directly generating an adjustable PWM signal wave to the fan unit 51, the axial fan 511 can directly use common fans on the market without customization.

[0042] The high-frequency filter circuit 62 is used to filter out the high-order harmonics in the PWM control signal.

[0043] This embodiment of the invention also provides an MRI system, which may include the aforementioned fan assembly or the aforementioned patient ventilation system.

[0044] As can be seen from the above solutions, in this embodiment, at least two axial flow fans are used instead of dedicated centrifugal fans to achieve high-pressure airflow to meet the patient's comfort requirements, and a shielding cover is used to solve the interference problem related to the PWM signal of the axial flow fans. This allows common PWM-controlled axial flow fans to be successfully applied to MRI systems. Because axial flow fans are small and low-cost, they not only meet the application requirements of compact MRI systems, making the placement of patient fans in compact MRI systems more flexible, but also significantly reduce costs. For example, the volume of the patient fan can be reduced by more than 40%, and the cost can be reduced by more than 1,000 yuan. Furthermore, the smaller size of the patient fan provides more space for cables, water pipes, or other components, improving system maintainability.

[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A fan assembly for a patient ventilation system in an MRI system, characterized by, include: A fan unit (51) includes at least two axial flow fans (511), which are fixedly arranged to achieve series pressurization of the air outlets; A magnetic shielding housing (52) is installed around the fan unit (51); An air inlet connector (53), disposed on the magnetic shielding housing (52) near the air inlet side of the fan unit (51), is used to connect to the air inlet duct (2) of the patient ventilation system; and An air outlet connector (54) is disposed on the side of the magnetic shielding housing (52) near the air outlet of the fan unit (51) for connection to the patient ventilation duct (3) of the patient ventilation system.

2. The fan assembly for a patient ventilation system in an MRI system of claim 1, wherein, Further includes: Fan mounting bracket for fixing the at least two axial flow fans (511).

3. A patient ventilation system for an MRI system, comprising: The system comprises an air inlet (1), an air inlet pipe (2), a patient ventilation pipe (3), and a patient ventilation outlet (4); characterized in that the patient ventilation system further includes: The fan assembly (5) for a patient ventilation system in an MRI system as described in claim 1 or 2; and The control unit (6) includes a PWM signal generation circuit (61) and a high-frequency filtering circuit (62); the PWM signal generation circuit (61) is used to generate a PWM control signal to control the speed of the wind turbine (51); the high-frequency filtering circuit (62) is used to filter out the high-order harmonics in the PWM control signal.

4. The patient ventilation system for an MRI system of claim 3, wherein, The air velocity at the patient ventilation opening (4) is maintained between 1 and 3 m / s.

5. The patient ventilation system for an MRI system of claim 3, wherein, The fan unit (51) has a pressure of 450-500 Pa.

6. An MRI system, characterized by include: The fan assembly (5) for a patient ventilation system in an MRI system as described in claim 1 or 2; or, The patient ventilation system for an MRI system as described in any one of claims 3 to 5.

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