Patent Description:
A cold box is a core device of an air separation plant. It includes a thermally insulated box, where a tower and pipes and valves connecting the tower are set. At present, cold boxes are divided into skid-mounted cold boxes and field-assembled cold boxes. For field-assembled cold boxes, parts need to be assembled on site. The workload is heavy, and the assembly quality is easily affected by the construction environment. For skid-mounted cold boxes, most assembly work is completed in a factory workshop where the environment is controlled. The product quality can be guaranteed, and the assembly cycle can be shortened. The two types of cold boxes are designed using the same material or similar materials and the same specification. As shown in <FIG> and <FIG>, a cold box includes a steel structural framework that is composed of parts such as a column <NUM>, a beam <NUM>, an oblique support <NUM> and an inter-beam support <NUM>, as well as panels that cover all sides of the steel structural framework and enclose the box.

For a skid-mounted cold box, two sections of steel structural framework and their corresponding first panels are generally assembled in a plant and the obtained upper and lower prefabricated structures are transported to the destination site for assembly on site. After the lower prefabricated structure is installed in place, a crane is mobilized to lift the upper prefabricated structure to the specified location so that it can be interconnected with the lower prefabricated structure. Full penetration welding is adopted for joining nodes <NUM> of the upper and lower columns <NUM> and nondestructive testing is performed for the welding seams to ensure that the joined columns <NUM> can vertically run through the cold box and transfer the shear force and bending moment generated by the upper part of the cold box. Then a second panel is connected to the column <NUM> and the beam <NUM> near the location where the prefabricated structures are joined, and seal welding is adopted for the joint node of the second panel. After all welding work is complete on site, the crane is dismissed.

Although the existing solution for assembling skid-mounted cold boxes can control the manufacturing and assembly quality of the parts of the prefabricated structures and simplify transportation and lifting, the following issues still exist: more manoeuver cost and operation time are required for the welding operation on site, for example, columns can be welded only after they are mounted in place and full penetration welding seams must go through nondestructive testing, requiring a long time and a high cost; and considering factors such as overhead work, the quality of welding seams cannot be guaranteed. During welding, the crane needs to stay for the work; when only one cold box is to be installed, it takes a longer time to use large machinery such as a crane, thereby causing low efficiency of its circulation and obviously increasing the cost of use. <CIT> describes a cold box according to the preamble of Claim <NUM>.

To solve the issues in the prior art, the present invention provides a skid-mounted cold box and its prefabricated assembly members and assembly method, aiming to reduce field assembly work as much as possible while not affecting the connection strength and airtightness of the cold box, so as to save field construction time and cost.

To achieve the foregoing purpose, a technical solution of the present invention provides assembly members to be joined to form a skid-mounted cold box according to Claim <NUM>.

Optionally, the vertical section of the ring beam of each first and second prefabricated structure is I-shaped and has a vertical beam, a joining surface and a non-joining surface and the joining surface and the non-joining surface are fixed on the vertical beam and are parallel to each other; and the vertical section of the frame structure of each first and second prefabricated structure is L-shaped and has a first surface and a second surface that are perpendicular to each other.

The first surface is connected to the inner side of edges of the first panel of the respective prefabricated structure and mounting holes for bolts are set at the joint so that the second panel can be fixed on the outer side of the first panel through the bolts; and the second surface is connected to the non-joining surface of the ring beam and extends towards the inner side of the framework.

Optionally, a connecting plate is set on the outer side of a location corresponding to a column on the ring beam. The connecting plate extends from the joining surface of the ring beam to the non-joining surface so that the assembled second panel can cover the connecting plate of the ring beam that is joined.

Optionally, mounting holes are set for a first bolt and a second bolt on the joining surface of the ring beam of each prefabricated structure, where the mounting hole for the first bolt is in a location corresponding to a column on the joining surface of the ring beam and the mounting hole for the second bolt is in another location on the joining surface of the ring beam; and the spacing of the mounting holes for the first bolt is smaller than the spacing of the mounting holes for the second bolt.

Optionally, the framework further includes:.

Another technical solution of the present invention provides a skid-mounted cold box according to Claim <NUM>.

Optionally, in each prefabricated structure,
the vertical section of the ring beam is I-shaped and has a vertical beam, a joining surface and a non-joining surface, where the joining surface and the non-joining surface are fixed on the vertical beam and are parallel to each other; the vertical section of the frame structure is L-shaped and has a first surface and a second surface that are perpendicular to each other.

The first surface is connected to the inner side of edges of the first panel and mounting holes for bolts are set at the joint so that the second panel can be fixed on the outer side of the first panel through the bolts. The second surface is connected to the non-joining surface of the ring beam and extends towards the inner side of the framework.

Optionally, on two adjacent prefabricated structures, a connecting plate is set on the outer side of the location corresponding to a column on each ring beam. The connecting plate extends from the joining surface of the ring beam to the non-joining surface so that the assembled second panel can cover the outer side of the connecting plates for the two prefabricated structures that are joined.

Optionally, a washer made of neoprene is set between the second panel and the first panel.

Optionally, bolts connecting ring beams in two adjacent prefabricated structures are friction-type high-strength bolts; and the spacing of the bolt in a location corresponding to a column on the joining surface of any ring beam is smaller than the spacing of bolts in other locations on the joining surface of the ring beam.

Optionally, any one prefabricated structure further includes:.

Another technical solution of the present invention provides a method according to Claim <NUM> [<NUM>] Compared with the prior art, the skid-mounted cold box according to the present invention and its assembly members and assembly method have the following advantage: the present invention can cancel all field welding seams without the need to weld columns or panels on site during field joining, which avoids nondestructive testing for columns, reduces field assembly work and saves testing time for relevant facilities and facility fees.

The skid-mounted cold box according to the present invention guarantees the strength of framework joints by connecting bolts for ring beams between adjacent prefabricated structures. Once the ring beams of the upper and lower prefabricated structures are aligned and bolts corresponding to columns are fastened on the joining surface, the crane can be dismissed. This saves the time required for field assembly and the measure cost to the maximum extent.

The framework of the prefabricated structure and the first panels according to the present invention are manufactured and assembled in a plant in a high-quality manner and the first panels provides good airtight effect for all frameworks and their columns. During field assembly, the second panel is connected through bolts to cover the gap formed between two ring beams from the outer side of the first panels after adjacent prefabricated structures are joined. In addition, a washer is set on the contact surface between the second panel and the first panels to guarantee effectively the airtightness of the cold box.

The following describes specific embodiments of the present invention in combination with <FIG>.

The present invention provides a skid-mounted cold box and its assembly members and assembly method to cancel all field welding operations for joining nodes. Adjacent prefabricated structures in the skid-mounted cold box are reliably connected by connecting bolts. The following takes the upper and lower prefabricated structure as an example. However, the present invention is not limited in other examples. More than two prefabricated structures of the cold box can be designed depending on actual requirements.

As shown in <FIG> and <FIG>, any prefabricated structure of the skid-mounted cold box according to the present invention includes a steel structural framework that is composed of parts such as column <NUM>, beam, oblique support, inter-beam support and ring beam <NUM>, as well as several first panels <NUM> that cover outer sides of the framework to completely enclose the outer sides of the framework and its columns <NUM>.

In the cold box where the cross section is square, the framework of each prefabricated structure has four columns <NUM> that run through the framework. Multiple beams are set between adjacent columns <NUM> and both ends of each beam are connected to a corresponding column <NUM>. Inter-beam supports that are parallel to beams are set between adjacent beams and both ends of an inter-beam support are connected to a corresponding column <NUM>. One end of each oblique support is connected to the middle of an inter-beam support to form a cross-shaped structure and the other end of the oblique support is connected to the joint between a corresponding column <NUM> and a beam or ring beam <NUM>.

The ring beam <NUM> is located at the joining end of a prefabricated structure, for example, the bottom of an upper prefabricated structure <NUM> and top of a lower prefabricated structure <NUM>. At the joining end of each prefabricated structure, a steel frame structure <NUM> is set to make the frame structure <NUM> be fixed on the inner side of a first panel <NUM> of the framework and surround the outer sides of columns <NUM>. The ring beam <NUM> is connected and fixed on the frame structure <NUM> to form a continuous entirety. The direction of the joining end of each prefabricated structure is different. Therefore, the joining surface of the ring beam <NUM> is its bottom or top. The top or bottom of the ring beam <NUM> opposite to the joining surface is called the non-joining surface.

In reference to <FIG> and <FIG>, mounting holes are set on the joining surface of each ring beam <NUM> to install a first bolt <NUM> and a second bolt <NUM> during field assembly and connect ring beams <NUM> of adjacent prefabricated structures. The first bolt <NUM> is installed in a location (for example, a corner) corresponding to a column <NUM> on the joining surface of the ring beam <NUM> and the second bolt <NUM> is installed in another location on the joining surface of the ring beam <NUM>. The spacing of the first bolt <NUM> is smaller than the spacing of the second bolt <NUM>.

On the outer side of the location corresponding to a column <NUM> on the ring beam <NUM>, a connecting plate <NUM> is set. Each connecting plate <NUM> extends from the joining surface of the ring beam <NUM> to the non-joining surface. The connecting plates <NUM> of two adjacent prefabricated structures may contact each other after they are joined but do not need to be fixed through welding or bolts.

In a factory workshop, all sides of frameworks of prefabricated structures are enclosed through several first panels <NUM> connected with parts such as beams and columns. The joining node of the first panel <NUM> may adopt seal welding to ensure the airtightness. Take the vertical section A-A shown in <FIG> as an example. The vertical section on any side of the ring beam <NUM> is I-shaped and a vertical beam is set to fix the joining surface and non-joining surface that are parallel to each other. The vertical section on any side of the frame structure <NUM> is L-shaped and has a first surface and a second surface that are perpendicular to each other. The first surface of the frame structure <NUM> is welded on the inner side of edges of a first panel <NUM> and the second surface of the frame structure <NUM> is welded on the non-joining surface of the ring beam <NUM> and extends towards the inner side of the framework. The first surface of the frame structure <NUM> is basically aligned with the outer edge of the non-joining surface. In <FIG>, B indicates that the frame structure <NUM> is connected to the first panel <NUM> and ring beam <NUM> through welding.

Each first panel <NUM> preferably covers the first surface of the frame structure <NUM> completely. At the welding point between the first surface of the frame structure <NUM> and the first panel <NUM>, a mounting hole that runs through the two is set and is used to install a third bolt <NUM> for connecting the second panel <NUM>. A washer <NUM> made of neoprene is set between the second panel <NUM> and the first panel <NUM> during field assembly. The second panel <NUM> can cover outer sides of connecting plates <NUM> (shown in <FIG>) of two ring beams <NUM> after field joining is complete. The two ring beams <NUM> are fixed and connected through the first bolt <NUM> and second bolt <NUM> installed on the joining surface.

The foregoing parts of prefabricated structures are connected through welding or bolts in a factory workshop according to design requirements and necessary quality testing is performed for finished products of the parts. Assuming the cross section of a framework is in another shape, for example, hexagon, the number of parts such as beams, columns and panels can be increased accordingly. This is not described here in detail.

The following describes the process of assembling a skid-mounted cold box on site:
As shown in <FIG>, upper and lower prefabricated structures <NUM> and <NUM> are transported to the predetermined site. After the lower prefabricated structure <NUM> is installed in place, a crane is mobilized to lift the upper prefabricated structure <NUM>, making the joining surfaces of ring beams <NUM> of the upper and lower prefabricated structure <NUM> and <NUM> be aligned and in contact. After the first bolt <NUM> is installed and fastened in a location corresponding to a column <NUM> on the surface of the ring beam <NUM>, the crane can be dismissed (or stay on site). Then in another location on the joining surface of the ring beam <NUM>, the second bolt <NUM> is installed and fastened. The frameworks of adjacent prefabricated structures according to the present invention are reliably connected through ring beams <NUM> connected based on bolts. The ring beams <NUM> are made of carbon steel. The first bolt <NUM> and the second bolt <NUM> for the ring beam <NUM> are friction-type high-strength bolts and are used to ensure that relative displacement does not occur between prefabricated structures under the action of wind load. The shear force and bending moment generated by the upper prefabricated structure <NUM> can be transferred to the prefabricated structure <NUM> under the joint action of the column <NUM> and ring beam <NUM> to further enhance the structural stiffness of frameworks.

After frameworks are connected, as shown in <FIG> and <FIG>, each second panel <NUM> is connected to two prefabricated structures through the second bolt <NUM> and the second panel <NUM> is connected to the outer side of the first panel <NUM> and corresponds to the welding point between the first surface of the frame structure <NUM> and the first panel <NUM>. Through the second panel <NUM>, the gap formed between two ring beams <NUM> after the upper and lower prefabricated structures <NUM> and <NUM> are joined is enclosed from the outer side of the second panel. A washer <NUM> made of neoprene is set between the second panel <NUM> and the first panel <NUM>.

Meanwhile, edges of the connecting plates <NUM> of two ring beams <NUM> are adjacent or in contact and the second panel <NUM> directly covers the outer side of the two connecting plates <NUM> to enclose the gap (corresponding to the gap in corresponding locations of columns <NUM> on the two ring beams <NUM>) between edges of the two connecting plates <NUM>. Now, the prefabricated structures of the skid-mounted cold box are joined and assembled on site.

In an example of a cold box with a design height of <NUM>, sizes can be designed for parts such as columns, beams, oblique supports and inter-beam supports according to general requirements. The ring beam <NUM> is I-shaped on any side and the width of the joining surface and non-joining surface is equal to the height of vertical beams. The height is <NUM> to <NUM> and is preferably <NUM>. Compared with a traditional cold box joined on site or a skid-mounted cold box, ring beams <NUM> are set in the upper and lower prefabricated structures <NUM> and <NUM> in the example. This causes little change to the overall height of the cold box after assembly. In reference to <FIG>, first bolts <NUM> on the joining surfaces of ring beams <NUM> corresponding to columns <NUM> are densely set. In this example, <NUM> first bolts <NUM> are installed in a corner of a ring beam <NUM>. The spacing (<NUM> to <NUM> in this example) of second bolts <NUM> installed in other locations of the joining surfaces of ring beams <NUM> is greater than the spacing of first bolts <NUM> installed in corners. When each side of a framework is connected to a second panel <NUM>, the height after the upper and lower ring beams <NUM> are joined is smaller than the height of the second panel <NUM> on the side so that the top and bottom of the second panel <NUM> that is connected can be respectively located above the non-joining surface of the upper ring beam <NUM> and below the non-joining surface of the lower ring beam <NUM>. This avoids joining nodes of beams and columns and guarantees better airtightness.

Claim 1:
Assembly members to be joined to form a skid-mounted cold box comprising first and second prefabricated structures (<NUM>, <NUM>), each comprising a framework, wherein multiple columns (<NUM>) running through the frameworks are set, several first panels (<NUM>) connecting the outer side of the framework, wherein the several first panels fully enclose the framework and outer sides of its columns and a ring beam (<NUM>) and mounting holes for bolts (<NUM>,<NUM>) are set on the ring beam so that the ring beam of the first prefabricated structure (<NUM>) can be connected to the similar ring beam of the second prefabricated structure (<NUM>) for joining through bolts during assembly;
characterized in that the assembly members comprise a second panel (<NUM>) and
the first and second prefabricated structures both comprise a frame structure (<NUM>) that is fixed on the inner side of edges of the first panels at a joining end of each prefabricated structure, wherein the ring beam (<NUM>) is fixed and
mounting holes for bolts set at the joint between each frame structure and the first panels so as to connect the second panel through bolts during assembly, and through the second panel, in order to completely enclose, on the outer side of the first panels, the gap formed at the ring beams of the first and second prefabricated structures after the first and second prefabricated structures are joined during assembly