Imaging device

Abstract

An imaging device includes: a first cylindrical housing with a closed first end and an open second end, and a second housing closing the second end to form an enclosed space with an imaging opening at its end. A third housing with a camera attached, having a lower thermal conductivity than the first housing, is inside the first housing in an airtight manner and divides the enclosed space to form a first empty space between the first and third housings, and a second empty space between the second and third housings. The camera is connected to cooling fins and a lens so that the distance between the lens and the imaging opening is less than 3 mm. Pressurized air supplied to the first housing passes through openings in the third housing, through the cooling fins, into the second empty space, and exits the imaging device through the imaging opening.

Description

1 IMAGING DEVICE Field 5 The invention relates to an imaging device for industrial use. Background The application of the invention concerns imaging devices cleaned with compressed air in industrial environments, such as break cameras in paper machine environments. 10 The use of compressed air to keep camera housings clean is known technology. For example, US Patent 6362889 describes a solution where an industrial camera system is kept clean using pressurized air. Directing airflow through the camera’s imaging opening also helps keep the opening itself clean. In industrial settings, cameras are often placed in locations where the ambient 15 temperature is high. In such cases, the cooling effect of flowing compressed air has been beneficial. In the era of digital cameras, additional computing power has been added, which also generates more heat inside the camera housing. Prolonged exposure to heat reduces the camera’s lifespan. This issue has been addressed by increasing the airflow through the camera housing. 20 Brief Description The purpose of this invention is to provide a compressed-air-cleaned imaging device that reduces the use of compressed air. The invention relates to a device according to independent claim 1. The device according to the invention can be used in various industrial 25 applications. List of Figures The invention, which is not limited to the embodiments presented below, is described in more detail with reference to the accompanying figures, in which: CA 3301108 Date reçue / Received date 2026-02-06 2 Figure 1 shows one embodiment of the imaging device according to the invention, Figures 2a and 2b show examples of using two lenses of different lengths in the imaging device. 5 Description of Embodiments The main components of an industrial imaging device are housing, the camera, and the lens. The housing itself may be a single unit or assembled from multiple parts. The housing limits the size of the camera and especially the size of the lens that can fit inside. To keep the housing clean, compressed air is typically supplied into it. A 10 slight overpressure inside the housing prevents external particles from accumulating inside. If the compressed air is dry, the internal humidity of the housing can also be maintained at the desired level. Compressed air is particularly important if there is no lens in front of the camera housing, but an imaging opening is used. In this case, supplying sufficient compressed air out through the imaging 15 opening keeps the opening clean. Producing compressed air requires energy, so minimizing its use is necessary. The amount of compressed air required is mainly influenced by two factors: keeping the camera sufficiently cool and keeping the imaging opening clean. The imaging device according to the invention provides a solution that minimizes the 20 amount of compressed air needed while addressing both factors. Figure 1 shows one embodiment of the imaging device 100. The outer surface of the imaging device comprises of a first and second housing. The first housing 101 is cylindrical in shape, with one end closed and the other end open. The cylindrical concept of the housing can be understood more broadly so that the housing 25 consists of a hollow cylindrical structure with one end surface removed. Thus, the invention can be implemented so that the outer surface of the housing does not need to be a circular cylinder but can, for example, be a prism. Similarly, the entire inner surface of the housing is not smooth but has various contours. The second housing 102 may have the same shape as the first housing or at least be a structure 30 that closes the open end of the first housing. The essential point is that the first and CA 3301108 Date reçue / Received date 2026-02-06 3 second housings can be joined at their edges to form a continuous hollow space. In the solution according to the invention, it is advantageous that the first and second housings can be easily detached from each other. For this purpose, there may be a separate thread or other quick-locking mechanism 112 between them. The second 5 housing has an imaging opening 106, which is a free opening without a lens. Air can therefore freely enter and exit the housing through the opening. A third housing 103 is a structure that can be placed inside the first housing so that it is considered to be airtight against the first housing 101. This creates two separate empty spaces: the first empty space 108 between the first housing and the 10 first end of the third housing, and the second empty space 109 between the second housing and the third housing. Airtightness means in the solution according to the invention that air cannot directly pass between the first housing 101 and the third housing 103. Airtightness can be achieved by precise dimensioning or by using another sealing solution, such as an O-ring 117. A camera 104, comprising a digital 15 camera and associated electronics, is attached to the third housing. The camera is thermally conductively connected to an assembly of cooling fins 111, which dissipates the camera’s heat. The camera is also connected to a lens 105 that focuses the imaged area onto the camera sensor. The third housing is placed inside the first housing so that when the imaging device is assembled, the distance 20 between the lens and the imaging opening of the second housing is small. The third housing 103 has one or more separate openings 110 through which air can freely flow between the first empty space 108 and the second empty space 109, passing through the cooling fins 111. The imaging device also includes a compressed air inlet 113 and a possible compressed air valve 114 to adjust the 25 airflow into first housing 101. Necessary feedthroughs 115 for electrical and data cables are also provided. The essential point of the invention is to minimize compressed air consumption. This is achieved through the following interconnected solutions: The imaging device 100 is typically placed in an environment with heavy environmental load. 30 For this reason, the first and second housings of the imaging device are made of metal, which withstands environmental stress. Metals conduct heat well, and CA 3301108 Date reçue / Received date 2026-02-06 4 therefore any high external temperature transfers to the inside of the housing. The third housing 103 has a lower thermal conductivity than the first housing 101. In practice, the third housing may be plastic, ceramic or metal . The goal is to prevent the surface heat of the first housing from transferring to the camera 104. The 5 camera’s and related electronics own heat output is dissipated to the cooling fins 111. The airflow essential for cooling the camera can now be directed only to cool the cooling fins. The airflow through the cooling fins can be restricted by one or more openings 110 in the third housing. The total area of the openings in the third housing affects how much airflow is available to keep the imaging opening 106 10 clean. In a preferred embodiment, the combined area of the one or more openings 110 in the third housing is larger than the area of the imaging opening 106. To keep the housing clean from debris coming through the imaging opening 106, the airflow out of the imaging opening must be sufficiently strong. The amount of flowing air can be reduced if the air flows fast enough over a longer distance in a 15 specific direction, i.e., toward the imaging opening 106. To achieve sufficient flow speed around the lens, the lens must be placed as close as possible to the imaging opening without blocking the airflow. At the same time, a narrow gap area 107 must be arranged between the lens 105 and the end of the second housing 102, where the air velocity increases. The inner surface of the second housing can be 20 shaped to match the contours of the lens end. This way, a narrower gap area 107 is formed around the lens end and the imaging opening of the second housing, where air flows rapidly toward the imaging opening. These contours can also influence the movement of air exiting the imaging opening so that the air exits at a desired angle. This affects how dirt accumulates around the imaging opening 106. 25 Preferably, the distance between the lens 105 and the imaging opening 106 of the second housing is small, for example, less than 3 mm but more than 0.2 mm. In practice, this distance can be measured as the distance between the lens end and the narrowest point of the imaging opening. In one embodiment of the invention, the lower thermal conductivity of the third 30 housing 103 is achieved by a separate insulation layer on the surface of the third housing. In practice, the third housing may mainly be made of the same metal as CA 3301108 Date reçue / Received date 2026-02-06 5 the first housing. However, an insulation layer made of material with lower thermal conductivity is formed at the edge of the third housing to prevent heat transfer from the inner edge of the first housing to the inside of the third housing. The goal is to prevent the surface heat of the first housing from transferring to the camera 5 104. In another embodiment, the inner surface of the edges of the first housing 101 is formed with grooves 121a, 121b running in the depth direction of the cylinder, whose ends are accessible from the second end of the first housing. Similarly, the third housing 103 has separate protrusions 120a, 120b that fit into the grooves 10 121a, 121b. When the third housing is fitted into at least two longitudinal grooves along their entire length, and the camera 104, lens 105, and first and second housings are assembled, the lens opening aligns within 3 mm accuracy behind the imaging opening in the end of the second housing. Figures 2a and 2b show examples of using two lenses 105a, 105b of different 15 lengths in the imaging device 100. In Figure 2a, a shorter lens 105a is attached to the camera 104. The camera and cooling fins 111 are attached to the third housing 103, which is fitted into grooves 121a inside the first housing 101 using protrusions 120a. The essential point is that there is a small distance between the lens 105a and the imaging opening 106. In Figure 2b, a longer lens 105b may be, 20 for example, 2 cm longer than the shorter lens 105a. A longer lens allows, for example, the camera’s precise imaging area to be focused farther away than with a shorter lens. The lens is attached to the camera 104, which is attached to the third housing 103. The third housing is fitted into different grooves 121b than when using the shorter lens, using protrusions 120b. This way, even with a longer lens 25 105b, a small distance remains between the lens and the imaging opening 106. This solution enables the camera 104 to be tightly attached to the third housing 103 even when the lens 105a, 105b is changed. When the camera is placed in different grooves 121a, 121b than before, the camera sensor 104 is naturally tilted differently relative to the horizon than before. In the 30 solution according to the invention, this is addressed by a camera mounting mechanism 116 that allows the camera to be attached at different radial angles so CA 3301108 Date reçue / Received date 2026-02-06 6 that the camera sensor’s horizontal level can be kept straight. The mounting mechanism 116 may be, for example, a clamp-like tightening ring. CA 3301108 Date reçue / Received date 2026-02-06

Claims

7 Claims 1. Imaging device (100) comprising: a first housing (101), which is cylindrical in shape and has a closed first end 5 and an open second end, a second housing (102), which closes the second end of the first housing to form a continuous enclosed space and which has an imaging opening (106) at its end, characterized in that a third housing (103), having a lower thermal 10 conductivity than the first housing, is placed inside the first housing in an airtight manner and divides the continuous enclosed space so that a first empty space (108) is formed between the first housing (101) and the third housing (103), and a second empty space (109) between the second housing (102) and the third housing (103), in which a camera (104) is attached to 15 the third housing, the camera being connected to an assembly of cooling fins (111) and a lens (105) so that the distance between the lens and the imaging opening (106) is less than 3 mm, and wherein there is an air path in the imaging device (100) such that pressurized air supplied to the first housing (101) passes through one or more openings (110) in the third housing 20 (103), through the camera’s cooling fins (111), into the second empty space (109), and exits the imaging device (100) through the imaging opening (106).

2. The imaging device (100) according to claim 1, wherein the combined area 25 of one or more openings (110) in the third housing (103) is greater than the area of the imaging opening (106).

3. The imaging device (100) according to claim 1 or 2, wherein the lower thermal conductivity of the third housing (103) is achieved by a separate 30 insulating layer on the surface of the third housing. CA 3301108 Date reçue / Received date 2026-02-06 8 4. The imaging device (100) according to any of claims 1–3, wherein the third housing (103) can be positioned correctly using at least two grooves (121a, 121b) extending in the depth direction of the cylinder, formed in the first housing (101). 5 5. The imaging device (100) according to claim 4, wherein the third housing is provided with at least two grooves (121a, 121b) of different lengths to allow two lenses (105) of different lengths to be mounted in the imaging device.

6. The imaging device (100) according to any of claims 1–4, wherein the imaging device includes a mounting mechanism (116) by which the radial 10 angle of the imaging device can be rotated to a desired position. CA 3301108 Date reçue / Received date 2026-02-06