Noise attenuation for nuclear imaging systems

Abstract

A cooling fan assembly for a nuclear imaging system is provided, wherein the fan assembly may include: a fan; an air inlet opening; an air outlet opening; and a honeycomb structured sheet mounted across the air inlet opening whereby when the fan is in operation and air flows through the air inlet opening, the honeycomb structured sheet promotes laminar flow of air at the air inlet opening and attenuates acoustic noise generated by the fan.

Description

Technical Field

[0001] This disclosure relates generally to the field of nuclear imaging systems, and more particularly to a technique for reducing the noise of cooling fans in such systems. Background Technology

[0002] In medical imaging systems (such as PET and PET / CT scanners) where the patient is positioned within a tunnel, cooling of the associated electronics is required, typically achieved by applying forced cooling air. Applying cooling air to such systems usually requires one or more fans and associated ductwork integrated into the patient tunnel structure to route the cooling air to where it is needed. The forced movement of cooling air through such systems generates substantial levels of audible noise, and when combined with the proximity of the patient tunnel structure within the imaging volume to the patient, the detrimental effects of noise from the cooling system on patient comfort become a significant consideration in the design of such medical imaging systems. For example, in existing PET and PET / CT scanner systems, the noise generated by the cooling system can be undesirably loud.

[0003] In conventional PET or PET / CT scanners, one or more cooling fans are enclosed within the gantry housing the gamma detector to ensure the performance of the gamma detector and other electronics therein. However, this guarantee comes at a cost. Each cooling fan pushes the noise level to a maximum threshold, and if a series of gamma detectors are to operate consistently, any detector that malfunctions (e.g., due to a faulty fan) cripples the entire system. With a large number of fan units, the statistical probability of system failure is detrimental to ensuring a reliable design. Therefore, systems incorporating multiple cooling fans have hidden costs associated with system downtime, maintenance, component replacement, and patient discomfort due to noise. Conversely, when considering the loss of gantry volume, distributing cooling airflow using only one or a few fans evenly surrounding the PET gantry may be difficult, especially when the airflow must be balanced and stable. Liquid cooling systems are even more expensive, and their failure can have catastrophic consequences. Therefore, improved cooling systems are needed for PET or PET / CT scanners.

[0004] Therefore, an improved device is desired to attenuate the noise generated by the cooling system. Summary of the Invention

[0005] This disclosure provides a nuclear imaging system including a cooling fan assembly comprising: a fan; an air inlet opening; and a honeycomb structured sheet mounted across the air inlet opening, whereby, when the fan is in operation and air flows through the air inlet opening, the honeycomb structured sheet promotes laminar flow of air at the air inlet opening and attenuates acoustic noise generated by the fan.

[0006] A cooling fan assembly is also disclosed, comprising: a fan; an air inlet opening; and a honeycomb structured sheet mounted across the air inlet opening, wherein when the fan is in operation and air flows through the air inlet opening, the honeycomb structured sheet promotes laminar flow of air at the air inlet opening and attenuates acoustic noise generated by the fan. Attached Figure Description

[0007] The features of the embodiments described herein will be more fully disclosed in the following detailed description, which will be attached. Figure 1 The similar numbers are considered, where similar numbers refer to similar parts.

[0008] Figure 1 and Figure 2 This is a cross-sectional view of a cooling fan assembly for a nuclear imaging system according to an embodiment of the present disclosure.

[0009] Figure 3 This is a view of a honeycomb structured sheet mounted across an air inlet opening according to an embodiment of the present disclosure.

[0010] Figure 4 This is a diagram illustrating the nuclear imaging system of this disclosure. Detailed Implementation

[0011] This description of exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which will be considered part of the complete written description. The drawings are not necessarily drawn to scale, and for clarity and brevity, certain features may be exaggerated or shown in a slightly schematic manner. In the description, relative terms such as “horizontal,” “vertical,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.), should be interpreted as referring to the orientation as described thereafter or as shown in the figures in the discussion. These relative terms are for convenience of description and are not generally intended to require a particular orientation. Terms including “inward” versus “outward,” “longitudinal” versus “lateral,” etc., are interpreted, where appropriate, relative to each other or relative to an axis of extension or axis of rotation or center. Unless otherwise explicitly described, terms relating to attachment, connection, etc. (such as “connection” and “interconnection”) refer to a relationship in which structures are directly or indirectly fixed or attached to each other through intervening structures, and an attachment or relationship that is both movable and rigid. The term "operable connection" is an attachment, link, or connection that allows related structures to operate as intended by virtue of that relationship.

[0012] refer to Figure 1 A cooling fan assembly 100 for a nuclear imaging system is disclosed, which incorporates a honeycomb structure in the form of a sheet. The fan assembly 100 includes a fan 120, an air inlet opening 115, and a honeycomb structured sheet 150 mounted across the air inlet opening 115. In the illustrated example, an inlet ring 110 defines the air inlet opening 115. The cooling fan assembly 100 includes a housing 130 that holds the fan 120.

[0013] When the fan is operating and air flows through the air inlet opening (indicated by arrow 170), the honeycomb structured sheet promotes laminar airflow at the air inlet opening and attenuates acoustic noise generated by the fan. The honeycomb structured sheet attenuates acoustic noise because the honeycomb structure absorbs sound waves by being installed in areas of high air velocity. In some preferred embodiments, the honeycomb structured sheet is formed of aramid fibers. An example of such a honeycomb structured sheet is Kevlar. ® honeycomb.

[0014] The honeycomb structured sheet formed from aramid fibers is a lightweight and flexible material. Therefore, when installed in the disclosed novel configuration of the cooling fan assembly of a nuclear imaging system, this material readily works together to significantly reduce noise levels. Because the aramid fiber-based honeycomb structured sheet readily works together, existing nuclear imaging systems can be easily retrofitted with the disclosed novel noise attenuation configuration.

[0015] refer to Figure 2 As ambient air is drawn toward the air inlet opening 115, the air velocity increases and reaches its maximum at or very close to the air inlet opening 115. Therefore, the region near the air inlet opening can be defined as a low-velocity region L and a high-velocity region H. The boundary between the low-velocity region L and the high-velocity region H is illustrated by a dashed line 50, labeled as a high-pressure drop region.

[0016] exist Figure 1 In the illustrated example, the honeycomb structured sheet is arranged in a flat planar configuration and extends vertically across the air inlet opening 115. In some embodiments, the flexible honeycomb structured sheet may be molded or otherwise formed into a bowl shape, which is consistent with... Figure 2 The curvature of the high-pressure drop region represented by the dashed line 50 in the middle is basically matched.

[0017] Figure 3 An example of a honeycomb structured sheet 150 is shown, which is mounted across an air inlet opening 115 of a cooling fan assembly of a PET / CT scanner. Because the aramid fiber honeycomb structured sheet is flexible, it can be cut to an appropriate size relative to the air inlet opening 115, inserted through the opening, allowed to expand across it, and then mounted to a frame of the air inlet opening using suitable fasteners known in the art. For example, the fasteners could be Velcro, adhesives, etc.

[0018] In many nuclear imaging systems (such as PET / CT scanners), the fans in the cooling fan assembly are high-speed centrifugal fans, and the air velocity is highest at the air inlet of the cooling fan assembly. Therefore, a large portion of the noise generated by the cooling fan assembly originates in the air inlet region, which is a high-speed airflow area. The inventors have discovered that the closer the honeycomb structured sheet is to the noise source, the more effective it is attenuating noise. Therefore, in some preferred embodiments, the honeycomb structured sheet 150 is mounted near the air inlet opening. Specifically, the honeycomb structured sheet 150 is mounted across the air inlet opening 115. In this configuration, the honeycomb structured sheet promotes laminar flow of air entering the cooling fan assembly through the air inlet opening.

[0019] In the case of more than one air inlet opening in a cooling fan assembly, the honeycomb structured sheet spans each of the air inlet openings.

[0020] Aramid fiber honeycomb structured sheets are highly effective for noise reduction in this application due to their high strength and extremely high percentage of open area, which allows for high airflow. In some embodiments, the honeycomb structured sheet has at least 90% open area, such that the placement of the honeycomb structured sheet across the air inlet opening does not adversely affect the airflow velocity. In some preferred embodiments, the honeycomb structured sheet has at least 97% open area.

[0021] The fan in the cooling fan assembly can be a centrifugal fan or an axial fan. In either case, providing a honeycomb structured sheet mounted across the air inlet opening of the cooling fan assembly can significantly attenuate the noise generated by the fan in operation.

[0022] In some embodiments of the cooling fan assembly, the honeycomb structured sheet covers at least 60% of the air inlet opening. In some embodiments, the honeycomb structured sheet covers at least 70% of the air inlet opening. In some embodiments, the honeycomb structured sheet covers at least 80% of the air inlet opening. In some embodiments, the honeycomb structured sheet covers at least 90% of the air inlet opening. In some embodiments, the honeycomb structured sheet covers 100% of the air inlet opening.

[0023] In many applications, honeycomb structured sheets can be easily mounted in high-speed airflow areas of cooling fan assemblies using attachment devices such as Velcro fasteners. Preferred embodiments of honeycomb structured sheets for this application include the following properties: flexibility; at least 90% open area; tensile strength ≥ 2,000 MPa; Young's modulus ≥ 68 GPa; and density ≤ 1.8 g / CC. In some preferred embodiments, the honeycomb structured sheet for this application includes: flexibility; at least 97% open area; tensile strength ≥ 3,000 MPa; Young's modulus ≥ 100 GPa; and density ≤ 1.5 g / CC.

[0024] refer to Figure 4 The paper also discloses a nuclear imaging system 200, which includes the cooling fan assembly 100 described above. The nuclear imaging system 200 includes a patient bed 210, a scanner gantry 230, and a patient tunnel 220. One or more of the cooling fan assemblies 100 are located within the scanner gantry 230.

[0025] It will be understood that the foregoing description is an exemplary embodiment of the present invention, and the present invention is not limited to the specific forms shown. Modifications may be made to the design and arrangement of the elements without departing from the scope of the present invention.

Claims

1. A cooling fan assembly for a nuclear imaging system, the fan assembly comprising: fan; Air inlet opening; as well as A honeycomb structured sheet is installed across the air inlet opening, thereby promoting laminar flow of air at the air inlet opening and attenuating acoustic noise generated by the fan when the fan is in operation and air flows through the air inlet opening.

2. The cooling fan assembly according to claim 1, wherein, The honeycomb structured sheet is formed from aramid fibers.

3. The cooling fan assembly according to claim 1, wherein, The honeycomb structured sheet has at least 90% open area.

4. The cooling fan assembly according to claim 1, wherein, The honeycomb structured sheet has an open area of ​​at least 97%.

5. The cooling fan assembly according to claim 1, wherein, The fan is a centrifugal fan.

6. The cooling fan assembly according to claim 1, wherein, The fan is an axial flow fan.

7. The cooling fan assembly according to claim 1, wherein, The honeycomb structured sheet covers at least 60% of the air inlet opening.

8. The cooling fan assembly according to claim 1, wherein, The honeycomb structured sheet covers at least 70% of the air inlet opening.

9. The cooling fan assembly according to claim 1, wherein, The honeycomb structured sheet covers at least 80% of the air inlet opening.

10. The cooling fan assembly of claim 1, wherein, The honeycomb structured sheet covers at least 90% of the air inlet opening.

11. The cooling fan assembly of claim 1, wherein, The honeycomb structured sheet covers 100% of the air inlet opening.

12. A nuclear imaging system, comprising: Cooling fan assembly, comprising: a fan; an air inlet opening; and A honeycomb structured sheet is installed across the air inlet opening, thereby promoting laminar flow of air at the air inlet opening and attenuating acoustic noise generated by the fan when the fan is in operation and air flows through the air inlet opening.

13. The nuclear imaging system according to claim 12, wherein, The honeycomb structured sheet is formed from aramid fibers.

14. The nuclear imaging system according to claim 12, wherein, The honeycomb structured sheet has at least 90% open area.

15. The nuclear imaging system according to claim 12, wherein, The honeycomb structured sheet has an open area of ​​at least 97%.

16. The nuclear imaging system according to claim 12, wherein, The fan is a centrifugal fan.

17. The nuclear imaging system according to claim 12, wherein, The fan is an axial flow fan.

18. The nuclear imaging system according to claim 12, wherein, The honeycomb structured sheet covers at least 60% of the air inlet opening.

19. The nuclear imaging system according to claim 12, wherein, The honeycomb structured sheet covers at least 70% of the air inlet opening.

20. The nuclear imaging system according to claim 12, wherein, The honeycomb structured sheet covers at least 80% of the air inlet opening.

21. The nuclear imaging system according to claim 9, wherein, The honeycomb structured sheet covers at least 90% of the air inlet opening.

22. The nuclear imaging system according to claim 9, wherein, The honeycomb structured sheet covers 100% of the air inlet opening.

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