Skid-mounted water electrolysis hydrogen production system
By integrating the electrolytic water hydrogen production equipment into the same base and designing a simplified hanging bar assembly, the high transportation and lifting cost problems caused by the independent equipment modules in the prior art are solved, and more efficient on-site installation and transportation are achieved.
Patent Information
- Application Number
- CN202421123171.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-05-21
AI Technical Summary
The existing electrolytic hydrogen production equipment has independent and different sizes, which requires a lot of time and cost to connect the pipelines on site, and the transportation and lifting costs are high, so the products cannot be delivered as soon as possible.
Design a skid-mounted electrolytic hydrogen production system to integrate hydrogen production equipment into the same base, including corner parts, bottom end beams, bottom side beams, floors and hanging bar components, simplifying on-site work and facilitating transportation, through hanging The design of the bar assembly reduces lifting complexity.
It reduces on-site workload, simplifies the transportation and lifting process, reduces transportation and lifting costs, and improves equipment flexibility and delivery efficiency.
Smart Images

Figure CN222251019U_ABST
Abstract
Description
Technical Field
[0001] The utility model generally relates to the technical field of hydrogen production, and more specifically to a skid-mounted water electrolysis hydrogen production system. Background Art
[0002] As an ideal clean energy, hydrogen energy has broad application prospects. Hydrogen energy can be divided into three categories according to its production source: gray hydrogen, blue hydrogen and green hydrogen. Gray hydrogen refers to hydrogen produced from fossil energy such as coal, oil and natural gas; blue hydrogen refers to hydrogen produced on the basis of gray hydrogen using carbon dioxide capture and storage technology, which can reduce carbon emissions by 90%; green hydrogen refers to hydrogen produced through the water electrolysis process. With the increasingly widespread application of hydrogen energy and the rapid development of renewable energy (wind energy, solar energy, etc.), the demand for water electrolysis hydrogen production systems is also increasing.
[0003] Skid-mounted equipment refers to a group of equipment fixed on a chassis made of angle steel or I-beam. Crowbars can be used to move and position the equipment. It is a form of combination of equipment frame and equipment as a whole. When skid-mounted equipment is connected to other equipment on the system, there is no need to install valves, instruments and other equipment in the middle. It only needs to complete the external connection of the electrical pipeline, which saves a lot of work in the on-site installation of equipment.
[0004] The existing water electrolysis hydrogen production equipment is mainly composed of main components, auxiliary components and electrical components. The existing hydrogen production device is composed of these components into their own skid-mounted modules, and these skid-mounted modules are then used to form the entire hydrogen production device. Each skid-mounted module is independent of each other, and the connecting pipelines between modules need to be connected on site, resulting in the skid-mounted module still needing pipeline connection operations after arriving at the project site, and the product cannot be delivered immediately. Each skid-mounted module uses its own skid-mounted frame and has different sizes, which requires multiple hoisting and transportation, and the transportation and hoisting costs are high.
[0005] Therefore, it is necessary to provide a skid-mounted water electrolysis hydrogen production system to at least partially solve the above problems. Utility Model Content
[0006] A series of simplified concepts are introduced in the utility model content section, which will be further described in detail in the detailed implementation section. The utility model content section of the utility model does not mean to attempt to define the key features and essential technical features of the technical solution claimed for protection, nor does it mean to attempt to determine the scope of protection of the technical solution claimed for protection.
[0007] In order to at least partially solve the above problems, the utility model provides a skid-mounted water electrolysis hydrogen production system, comprising a hydrogen production device and a base, wherein the hydrogen production device is connected to the upper surface of the base, and the base comprises:
[0008] Corner fittings, which are used to cooperate with container transport vehicles;
[0009] a bottom end beam extending in a width direction of the base and connected to the corner piece;
[0010] A bottom side beam extending along the length direction of the base and connected to the corner piece, wherein both the bottom end beam and the bottom side beam do not protrude downward from the corner piece;
[0011] a floor panel connected to upper surfaces of both the bottom end beam and the bottom side beam;
[0012] The suspension bar assembly comprises a suspension bar extending in the width direction of the base and connected to the bottom side beam movably along its own axial direction.
[0013] Optionally, the bottom side beam has a mounting hole, and the suspension bar assembly further includes:
[0014] a sleeve, the sleeve being connected to the assembly hole and sleeved on the outer circumference of the suspension bar, the suspension bar being movably connected to the sleeve, and the axial dimension of the suspension bar being larger than the axial dimension of the sleeve;
[0015] An end plate is connected to both ends of the suspension bar along the axial direction of the suspension bar, and the end plate protrudes from the assembly hole along the radial direction of the suspension bar to prevent the suspension bar from slipping relative to the sleeve.
[0016] Optionally, the sleeve protrudes from the bottom side beam along its own axial direction.
[0017] Optionally, both the bottom end beam and the bottom side beam have an avoidance gap, the corner piece is connected to the avoidance gap, and the upper surface of the corner piece is lower than the upper surfaces of both the bottom end beam and the bottom side beam.
[0018] Optionally, there are two bottom side beams, and the two bottom side beams are spaced apart along the width direction of the base. The base also includes a bottom cross beam, which extends along the width direction of the base, and the bottom cross beam is connected to the two bottom side beams, and the bottom cross beam does not protrude from the bottom side beams along the height direction of the base.
[0019] Optionally, the hydrogen production equipment comprises:
[0020] a main body assembly connected to the base;
[0021] an auxiliary component connected to the base, the auxiliary component being spaced apart from the main component along a length direction of the base; and
[0022] An electrical component is connected to the base and is located between the main component and the auxiliary component.
[0023] Optionally, the main body component includes:
[0024] an electrolytic cell connected to the base, the electrolytic cell being connected to both the auxiliary component and the electrical component;
[0025] A gas-liquid separation member connected to both the electrolytic cell and the base, wherein the gas-liquid separation member is spaced from the electrolytic cell along a length direction of the base;
[0026] A gas purification component is connected to both the gas-liquid separation component and the base, the gas purification component and the gas-liquid separation component are spaced apart along the length direction of the base, and the gas-liquid separation component is located between the gas purification component and the electrolytic cell.
[0027] Optionally, the base further includes a support beam, which extends along the width direction of the base, is located below the floor and is connected to the bottom side beam, and is used to support the electrolytic cell.
[0028] Optionally, the auxiliary components include:
[0029] a lye tank connected to the base;
[0030] A pure water tank, the pure water tank is connected to the base and the alkali liquid tank, and the pure water tank is spaced apart from the alkali liquid tank along the width direction of the base;
[0031] A water purifier is connected to the base, the water purifier is spaced apart from the alkali liquid tank and the pure water tank along the length direction of the base, and the water purifier is located on a side of the alkali liquid tank and the pure water tank away from the electrical components.
[0032] Optionally, the electrical component comprises:
[0033] A rectifier cabinet connected to the base;
[0034] A control cabinet, the control cabinet is connected to the base, the control cabinet and the rectifier cabinet are spaced apart along the width direction of the base, and the control cabinet protrudes from the rectifier cabinet along the length direction of the base;
[0035] A transformer is connected to the base, the transformer is spaced apart from the rectifier cabinet and the control cabinet along the length direction of the base, and the transformer is located on a side of the rectifier cabinet and the control cabinet away from the main assembly.
[0036] According to the skid-mounted water electrolysis hydrogen production system of the utility model, by integrating the hydrogen production equipment onto the same base, the workload on site is reduced and centralized transportation using a transport vehicle is facilitated. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The following drawings of the embodiments of the present invention are used as part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the principles of the present invention. In the drawings,
[0038] Figure 1 It is a three-dimensional structural schematic diagram of a skid-mounted water electrolysis hydrogen production system according to a preferred embodiment of the utility model;
[0039] Figure 2 for Figure 1 An exploded schematic diagram of the base of the skid-mounted water electrolysis hydrogen production system is shown;
[0040] Figure 3 for Figure 2 Schematic diagram of some structures in ;
[0041] Figure 4 A schematic diagram of the structure of the connection between the suspension bar assembly and the bottom side beam; and
[0042] Figure 5 for Figure 1 Schematic top view of .
[0043] Description of reference numerals:
[0044] 1 Hydrogen production system 10 Hydrogen production equipment
[0045] 11 Main assembly 12 Electrical assembly
[0046] 13 Auxiliary components 20 Base
[0047] 20a Avoidance notch 21 Angle piece
[0048] 22 Bottom end beam 23 Bottom side beam
[0049] 23a Mounting hole 24 Floor
[0050] 25 Lifting bar assembly 26 Bottom beam
[0051] 27 Support beam 111 Gas purification component
[0052] 112 Gas-liquid separation component 113 Electrolytic cell
[0053] 121 Rectifier cabinet 122 Control cabinet
[0054] 123 Transformer 131 Alkali liquid tank
[0055] 132 Pure water tank 133 Pure water machine
[0056] 134 fixed seat 251 hanging bar
[0057] 252 sleeve 253 end plate
[0058] 1211 Rectifier cabinet body 1212 Rectifier cabinet seat
[0059] 1221 Control cabinet body 1222 Control cabinet seat DETAILED DESCRIPTION
[0060] In the following description, a large number of specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.
[0061] In order to fully understand the implementation of the present invention, a detailed structure will be presented in the following description. Obviously, the implementation of the implementation of the present invention is not limited to the specific details familiar to those skilled in the art.
[0062] It should be understood that the purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention, and the singular forms "a", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. When the terms "comprise" and / or "include" are used in this specification, it indicates the presence of the features, integral bodies, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integral bodies, steps, operations, elements, components and / or combinations thereof.
[0063] Ordinal numbers such as "first" and "second" cited in the present invention are merely identifiers and do not have any other meaning, such as a specific order. Moreover, for example, the term "first component" itself does not imply the existence of a "second component", and the term "second component" itself does not imply the existence of a "first component". It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer" and similar expressions used in the present invention are for illustrative purposes only and are not limiting.
[0064] Hereinafter, specific embodiments of the present invention will be described in more detail with reference to the accompanying drawings. These drawings show representative embodiments of the present invention and are not intended to limit the present invention.
[0065] The utility model provides a skid-mounted water electrolysis hydrogen production system.
[0066] See also Figure 1 The hydrogen production system 1 may include a hydrogen production device 10 and a base 20, wherein the hydrogen production device 10 is connected to the upper surface of the base 20. Figures 2 to 4 The base 20 may include an angle piece 21, a bottom end beam 22, a bottom side beam 23, a floor 24 and a boom assembly 25. The angle piece 21 is used to cooperate with a container transport vehicle. The bottom end beam 22 extends along the width direction of the base 20 and is connected to the angle piece 21, and the bottom side beam 23 extends along the length direction of the base 20 and is connected to the angle piece 21. Both the bottom end beam 22 and the bottom side beam 23 do not protrude downward from the angle piece 21, so as to facilitate the cooperation and installation of the angle piece 21 and the transport vehicle. It can be understood that the floor 24 is connected to the upper surface of both the bottom end beam 22 and the bottom side beam 23. Please refer to Figure 3 and Figure 4 The suspension bar assembly 25 includes a suspension bar 251 extending along the width direction of the base 20 and movably connected to the bottom side beam 23 along its own axial direction.
[0067] According to the skid-mounted water electrolysis hydrogen production system of the utility model, by integrating the hydrogen production equipment 10 onto the same base 20, the workload on site is reduced and centralized transportation using a transport vehicle is facilitated.
[0068] It is understandable that after some hydrogen production equipment 10 are integrated onto the same base 20, if the length and width of the base 20 are relatively small, the suspension bar assembly 25 can be connected to the bottom end beam 22, that is, the suspension bar 251 extends along the length direction of the base 20. The utility model takes into account that after the actual hydrogen production equipment 10 is integrated, the length and width of the base 20 are relatively large. If the suspension bar assembly 25 is connected to the bottom end beam 22, the base 20 may be broken during hoisting, so it is preferred that the suspension bar 251 extends along the width direction of the base 20.
[0069] Please continue reading Figure 3 and Figure 4, further, the bottom side beam 23 may have an assembly hole 23a. The suspension bar assembly 25 also includes a sleeve 252 and an end plate 253, the sleeve 252 is connected to the assembly hole 23a and is sleeved to the outer periphery of the suspension bar 251, and the suspension bar 251 is movably connected to the sleeve 252. It can be understood that in order to prevent the suspension bar 251 from slipping relative to the sleeve 252, the end plate 253 is connected to both ends of the suspension bar 251 along the axial direction of the suspension bar 251, and the end plate 253 protrudes from the assembly hole 23a along the radial direction of the suspension bar 251. Accordingly, the axial dimension of the suspension bar 251 is greater than the axial dimension of the sleeve 252. In addition, in order to facilitate the welding and fixing of the sleeve 252 to the bottom side beam 23, the sleeve 252 can be constructed so that the sleeve 252 protrudes from the bottom side beam 23 along its own axial direction.
[0070] See also Figure 2 and Figure 3 In order to improve the connection strength between the bottom end beam 22 and the bottom side beam 23 and the corner piece 21, the bottom end beam 22 and the bottom side beam 23 may have an avoidance notch 20a, and the corner piece 21 is connected to the avoidance notch 20a. After the connection is completed, the upper surface of the corner piece 21 is lower than the upper surfaces of the bottom end beam 22 and the bottom side beam 23. It can be understood that the bottom end beam 22 and the bottom side beam 23 are only overlapped with the corner piece 21 by the avoidance notch 20a. In some embodiments not shown, the bottom end beam 22 and the bottom side beam 23 may also be directly connected to the corner piece 21. In comparison, the connection strength between the bottom end beam 22 and the bottom side beam 23 and the corner piece 21 will be reduced due to the lack of the bearing effect of the overlap surface of the avoidance notch 20a. In addition, the corner piece 21 may be constructed to protrude downward from the bottom end beam 22 and the bottom side beam 23. When placed, the corner piece 21 contacts and bears the load on the placement surface, and the pressure it receives is relatively large. In this embodiment, the bottom surface of the corner piece 21 is preferably configured to be flush with the bottom surfaces of the bottom end beam 22 and the bottom side beam 23 so that the corner piece 21 is supported together with the bottom end beam 22 and the bottom side beam 23 .
[0071] Please continue reading Figure 2 and Figure 3 , there are two bottom side beams 23, and the two bottom side beams 23 are spaced apart along the width direction of the base 20. In order to improve the structural strength of the base 20, the base 20 may further include a bottom cross beam 26, which extends along the width direction of the base 20 and is connected to the two bottom side beams 23. In order to facilitate the stable placement of the base 20 and the laying of the floor 24, the bottom cross beam 26 does not protrude from the bottom side beams 23 along the height direction of the base 20.
[0072] See also Figure 1 and Figure 5, the hydrogen production equipment 10 may include a main component 11, an auxiliary component 13 and an electrical component 12. The main component 11 is connected to the base 20, the auxiliary component 13 is connected to the base 20, and the auxiliary component 13 is spaced apart from the main component 11 along the length direction of the base 20. The electrical component 12 is connected to the base 20, and the electrical component 12 is located between the main component 11 and the auxiliary component 13. Specifically, the main component 11 may include a gas purification component 111, a gas-liquid separation component 112 and an electrolyzer 113. The electrolyzer 113 is connected to the base 20, and the electrolyzer 113 is connected to both the auxiliary component 13 and the electrical component 12. The gas-liquid separation component 112 is connected to both the electrolyzer 113 and the base 20, and the gas-liquid separation component 112 is spaced apart from the electrolyzer 113 along the length direction of the base 20. The gas purification component 111 is connected to the gas-liquid separation component 112 and the base 20 . The gas purification component 111 and the gas-liquid separation component 112 are spaced apart along the length direction of the base 20 . The gas-liquid separation component 112 is located between the gas purification component 111 and the electrolytic cell 113 .
[0073] See also Figure 2 Considering the heavy weight of the electrolytic cell 113, in order to prevent the electrolytic cell 113 from damaging the base 20, the base 20 may further include a support beam 27, and the support beam 27 extends along the width direction of the base 20. Figure 2 In the embodiment, two support beams 27 are included. The support beams 27 are located below the floor 24 and connected to the bottom side beams 23 (for example, the upper surface of the support beams 27 is welded to the bottom surface of the floor 24). After the electrolytic cell 113 is placed on the floor 24, the support beams 27 bear its weight to avoid damaging the base 20.
[0074] Please continue reading Figure 1 and Figure 5 , the auxiliary component 13 may include an alkali liquid tank 131, a pure water tank 132 and a pure water machine 133. The alkali liquid tank 131 is connected to the base 20, the pure water tank 132 is connected to the base 20 and the alkali liquid tank 131, and the pure water tank 132 is spaced apart from the alkali liquid tank 131 along the width direction of the base 20. The pure water machine 133 is connected to the base 20, and the pure water machine 133 is spaced apart from the alkali liquid tank 131 and the pure water tank 132 along the length direction of the base 20, and the pure water machine 133 is located on the side of the alkali liquid tank 131 and the pure water tank 132 away from the electrical component 12. Further, in order to facilitate the connection between the alkali liquid tank 131 and the pure water tank 132 and the base 20, the auxiliary component 13 may also include a fixing seat 134, which is connected to the bottom of the alkali liquid tank 131 and the pure water tank 132 and connected to the base 20.
[0075] The electrical component 12 may include a rectifier cabinet 121, a control cabinet 122, and a transformer 123. The rectifier cabinet 121 is connected to the base 20, the control cabinet 122 is connected to the base 20, and the control cabinet 122 and the rectifier cabinet 121 are spaced apart in the width direction of the base 20, and the control cabinet 122 protrudes from the rectifier cabinet 121 in the length direction of the base 20. The transformer 123 is connected to the base 20, and the transformer 123 and the rectifier cabinet 121 and the control cabinet 122 are spaced apart in the length direction of the base 20, and the transformer 123 may be located on a side of the rectifier cabinet 121 and the control cabinet 122 away from the main component 11. Specifically, the transformer 123 usually has its own chassis, and its connection with the base 20 is more convenient. The rectifier cabinet 121 may include a rectifier cabinet body 1211 and a rectifier cabinet seat 1212. It can be understood that the rectifier cabinet body 1211 is connected to the rectifier cabinet seat 1212, the rectifier cabinet seat 1212 is located below the rectifier cabinet body 1211, and the rectifier cabinet seat 1212 is connected to the base 20. Correspondingly, the control cabinet 122 may include a control cabinet body 1221 and a control cabinet seat 1222, the control cabinet seat 1222 is located below the control cabinet body 1221, the control cabinet body 1221 is connected to the control cabinet seat 1222, and the control cabinet seat 1222 is connected to the base 20.
[0076] According to the skid-mounted water electrolysis hydrogen production system of the utility model, by integrating the hydrogen production equipment 10 onto the same base 20, the workload on site is reduced and centralized transportation using a transport vehicle is facilitated. In addition, the hydrogen production system 1 is convenient to be transported with container transport vehicles such as container trucks, and the lifting bar 251 is retractable, which is convenient for lifting the hydrogen production system 1. The modular integration of the hydrogen production equipment 10 on the base 20 facilitates replacement of equipment of different specifications according to usage requirements, thereby improving the flexibility of use.
[0077] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field of the present invention. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present invention. Terms such as "setting" appearing in this article may indicate that one component is directly attached to another component, or that one component is attached to another component through an intermediate. Features described in this article in one embodiment may be applied to another embodiment alone or in combination with other features, unless the feature is not applicable in the other embodiment or otherwise specified.
[0078] The utility model has been described through the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the utility model to the described embodiments. It can be understood by those skilled in the art that more variations and modifications can be made according to the teachings of the utility model, and these variations and modifications all fall within the scope of the protection claimed by the utility model.
Claims
1. A skid-mounted water electrolysis hydrogen production system, characterized in that: The invention comprises a hydrogen production device and a base, wherein the hydrogen production device is connected to the upper surface of the base, and the base comprises: Corner fittings, which are used to cooperate with container transport vehicles; a bottom end beam extending in a width direction of the base and connected to the corner piece; A bottom side beam extending along the length direction of the base and connected to the corner piece, wherein both the bottom end beam and the bottom side beam do not protrude downward from the corner piece; a floor panel connected to upper surfaces of both the bottom end beam and the bottom side beam; The suspension bar assembly comprises a suspension bar extending in the width direction of the base and connected to the bottom side beam movably along its own axial direction.
2. The skid-mounted water electrolysis hydrogen production system according to claim 1, characterized in that: The bottom side beam has a mounting hole, and the suspension bar assembly further includes: a sleeve, the sleeve being connected to the assembly hole and sleeved on the outer circumference of the suspension bar, the suspension bar being movably connected to the sleeve, and the axial dimension of the suspension bar being larger than the axial dimension of the sleeve; An end plate is connected to both ends of the suspension bar along the axial direction of the suspension bar, and the end plate protrudes from the assembly hole along the radial direction of the suspension bar to prevent the suspension bar from slipping relative to the sleeve.
3. The skid-mounted water electrolysis hydrogen production system according to claim 2, characterized in that: The sleeve protrudes from the bottom side beam along its axial direction.
4. The skid-mounted water electrolysis hydrogen production system according to claim 1, characterized in that: The bottom end beam and the bottom side beam both have an avoidance gap, the corner piece is connected to the avoidance gap, and the upper surface of the corner piece is lower than the upper surfaces of the bottom end beam and the bottom side beam.
5. The skid-mounted water electrolysis hydrogen production system according to claim 4, characterized in that: There are two bottom side beams, and the two bottom side beams are spaced apart along the width direction of the base. The base also includes a bottom cross beam, which extends along the width direction of the base and is connected to the two bottom side beams. The bottom cross beam does not protrude from the bottom side beams along the height direction of the base.
6. The skid-mounted water electrolysis hydrogen production system according to claim 1, characterized in that: The hydrogen production equipment comprises: a main body assembly connected to the base; an auxiliary component connected to the base, the auxiliary component being spaced apart from the main component along a length direction of the base; and An electrical component is connected to the base and is located between the main component and the auxiliary component.
7. The skid-mounted water electrolysis hydrogen production system according to claim 6, characterized in that: The main body component comprises: an electrolytic cell connected to the base, the electrolytic cell being connected to both the auxiliary component and the electrical component; A gas-liquid separation member connected to both the electrolytic cell and the base, wherein the gas-liquid separation member is spaced from the electrolytic cell along a length direction of the base; A gas purification component is connected to both the gas-liquid separation component and the base, the gas purification component and the gas-liquid separation component are spaced apart along the length direction of the base, and the gas-liquid separation component is located between the gas purification component and the electrolytic cell.
8. The skid-mounted water electrolysis hydrogen production system according to claim 7, characterized in that: The base further includes a support beam extending along a width direction of the base, the support beam being located below the floor and connected to the bottom side beam, and the support beam being used to support the electrolytic tank.
9. The skid-mounted water electrolysis hydrogen production system according to claim 6, characterized in that: The auxiliary components include: a lye tank connected to the base; A pure water tank, the pure water tank is connected to the base and the alkali liquid tank, and the pure water tank is spaced apart from the alkali liquid tank along the width direction of the base; A water purifier is connected to the base, the water purifier is spaced apart from the alkali liquid tank and the pure water tank along the length direction of the base, and the water purifier is located on a side of the alkali liquid tank and the pure water tank away from the electrical components.
10. The skid-mounted water electrolysis hydrogen production system according to claim 6, characterized in that: The electrical components include: A rectifier cabinet connected to the base; A control cabinet, the control cabinet is connected to the base, the control cabinet and the rectifier cabinet are spaced apart along the width direction of the base, and the control cabinet protrudes from the rectifier cabinet along the length direction of the base; A transformer is connected to the base, the transformer is spaced apart from the rectifier cabinet and the control cabinet along the length direction of the base, and the transformer is located on a side of the rectifier cabinet and the control cabinet away from the main assembly.
