Patent Application
20200122980
The present invention generally relates to the manufacture of air-cooled heat exchangers, and more particularly, but not by way of limitation, to an improved tool for lifting heavy components during the manufacturing a heat exchanger.
Heat exchangers are used in a wide variety of industrial applications. A process fluid, either a gas or a liquid, is passed through a series of cooling tubes while air is mechanically passed over the exterior of the cooling tubes. The air absorbs heat from the cooling tubes, thereby lowering the temperature of the fluid within the tubes. The cooling tubes may include lateral or axial fins to aid in heat transfer.
The cooling tubes extend between two or more headers (or header boxes) positioned on opposite sides of the heat exchanger. The headers include an inlet or an outlet to permit the flow of the process fluid through the heat exchanger. In many applications, the process fluid is under elevated temperatures and pressures. To safely contain the elevated pressure of the process fluid, the headers are manufactured by welding substantial metal plates together. Although effective, the metal plates used to fabricate the headers are heavy. For large air-cooled heat exchangers, each header may weigh up to 10,000 pounds.
In past, headers have been moved around the manufacturing facility by inserting one or more steel posts through holes in the headers and securing a chain around the ends of the steel posts and around the header. This approach is undesirable because the chain may slip or twist about the steel posts and the chain wrap around the header frustrates efforts to lay the header down without interference from the chain. The existing method of lifting headers is time-consuming and requires skilled application to avoid damage or injury. Accordingly, there is a need for an improved system and method for lifting and moving headers during the manufacture of large air-cooled heat exchangers. The presently preferred embodiments are directed to these and other deficiencies in the prior art.
There are several aspects of the present subject matter which may be embodied separately or together in the devices and systems described and claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to preclude the use of these aspects separately or the claiming of such aspects separately or in different combinations as set forth in the claims appended hereto.
In one aspect, a fixture for lifting a heat exchanger header having tubing apertures includes a first leg including a first receiver slot and a second leg including a second receiver slot. A first load arm is pivotally attached to an upper portion of the first leg and a second load arm is pivotally attached to an upper portion of the second leg and the upper end portions of the first and second load arms are configured to be engaged by a lifting device. A first scissor arm has a pivot end pivotally attached to the second leg and a sliding end portion attached to the first leg by the first receiver slot. A second scissor arm has a pivot end pivotally attached to the first leg and a sliding end portion attached to the second leg by the second receiver slot. A first connection plate is secured to a lower portion of the first leg and includes a first connection aperture. A second connection plate is secured to a lower portion of the second leg and includes a second connection aperture. The first and second connection apertures are configured to be aligned with a tubing aperture of a heat exchanger header.
In another aspect, a fixture for lifting a heat exchanger header having tubing apertures includes a first leg including a first receiver slot and a second leg including a second receiver slot. A first load arm is pivotally attached to an upper portion of the first leg and a second load arm is pivotally attached to an upper portion of the second leg. The upper end portions of the first and second load arms are configured to be engaged by a lifting device. A first scissor arm is pivotally attached to the second leg and slidingly attached to the first leg by the first receiver slot. A second scissor arm is pivotally attached to the first leg and slidingly attached to the second leg by the second receiver slot. A first connection plate is secured to a lower portion of the first leg and a second connection plate is secured to a lower portion of the second leg. The first and second connection plates are configured for connection to a tubing aperture of a heat exchanger header.
In still another aspect, a method of lifting a heat exchanger header having tubing apertures includes the steps of: connecting a lift device to a lift fixture, where the lift fixture includes opposing first and second connection plates having first and second connection apertures and a scissor mechanism having a lift point, where the scissor mechanism is configured to move the first and second connection plates towards one another when the lift point is raised, placing the first connection plate and the second connection plate of the lift fixture on opposite sides of the heat exchanger header, aligning the first connection aperture of the first connection plate and the second aperture of the second connection plate with a tubing aperture of the heat exchanger header, inserting a rod through the first and second connection apertures and the tubing aperture of the heat exchanger header and raising the lift point of the lift fixture using the lift device so that the first and second connection plates cooperatively grip the heat exchanger header.
Referring to
In the depicted embodiment, the header lift fixture 100 includes a pair of legs 102a and 102b, a pair of scissor arms 104a and 104b, a pair of load arms 106a and 106b, and pair of connection plates 108a and 108b. Each of the legs 102a and 102b includes a receiver slot 110a and 110b and a receiver hole 112a (
The scissor arms 104a and 104b are sized such that each scissor arm 104a 104b extends between the two legs 102a and 102b. More specifically, a first scissor arm 104a extends from the receiver hole 112a on the second leg 102b to the receiver slot 110a on the first leg 102b. A second scissor arm 104b extends from the receiver hole 112a on the first leg 102a to the receiver slot 110b on the second leg 102b. The scissor arms 104a and 104b can thus be pinned or bolted between the first and second legs 102a and 102b to permit the relative rotation of the scissor arms 104a and 104b with respect to the legs 102a and 102b. Similarly, the load arms 106a and 106b are each connected to a separate one of the legs 102a and 102b through load arm bolt holes 118a and 118b. The opposite ends of the load arms 106 are coupled to the load bearing connector 204 of the lifting device 202 through a lift point such as lift opening 120 (formed through the overlapping upper end portions of load arms 106a and 106b). The lift point may take alternative forms such as a bracket or member connected to the lift opening 120.
In certain embodiments, it may be desirable to bolster the strength of the legs 102a and 102b with braces 126a and 126b. The optional braces 126a and 126b limit extent to which the legs 102a and 102b flex during a lift. The braces 126a and 126b can be welded to the legs 102a and 102b. Unless otherwise indicated, the various components of the header lift fixture 100 are manufactured from high carbon, high strength steel.
As best illustrated in
The connection plates 108a and 108b are secured to the lower end of each of the legs 102a and 102b. In some embodiments, the connection plates 108a and 108b are welded to the lower end of the legs 102a and 102b. The connection plates 108a and 108b include one or more connection apertures 122a, 123a and 122b and 123b that are sized to permit carrying rods 124 and 125 (
Generally, the legs 102a and 102b, scissor arms 104a and 104b and lifting arms 106a and 106b cooperate to produce a “scissor” mechanism in which the application of a tensile load between the connection plates 108 and the lifting arms 106, such as which occurs when the lift point 120 is pulled vertically upwards while carrying rods extend through a header and the connection apertures of the connection plates 108a and 108b, causes the legs 102 to be drawn together as the header lift fixture 100 elongates, thereby applying a compressive force to the header 200 between the connection plates 108a and 108b.
In an exemplary method of use, a load bearing connector 204 (
Once the header lift fixture 100 has been preliminarily connected to the header 200 with the carrying rods 124, the lifting device 202 raises the header lift fixture 100. As the header lift fixture 100 is raised and tension is applied by the weight of the header 200, the header lift fixture 100 elongates through the scissor mechanism and the connection plates 108 apply a compressive lateral “squeeze” force to stabilize the header 200 during the lift while securing the carrying rods 124 (and 125) within the connection apertures 122a, 123a and 122b, 123b.
When the lift is complete, the lifting device 202 lowers the header 200 until the weight of the header 200 is no longer transferred through the header lift fixture 100. Once the header lift fixture 100 is not exposed to the weight of the header 200, the carrying rods 124 (and 125) can be removed and the legs 102a and 102b can be separated up and away from the header 200.
Thus, the header lift fixture 100 provides a safe, reliable and efficient way to lift headers 200 during the manufacture and assembly of heat exchangers. Although the exemplary embodiments have been depicted in connection with the header 200, it will be appreciated that in other embodiments the header lift fixture 100 can be used to lift other components or equipment without significant modification. It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and functions of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms expressed herein. It will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other systems without departing from the scope and spirit of the present invention.
This application claims the benefit of U.S. Provisional Application No. 62/747,633, filed Oct. 18, 2018, the contents of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62747633 | Oct 2018 | US |
