IES61652B2 - Improved heat exchanger installation - Google Patents

Description

The present invention relates to the installation of heat exchangers and more particularly to the installation of * heat exchange coils in water storage vessels.

In general, heat exchange tubes or coils are inserted into water storage vessels by punching one or more holes in the wall of the vessel and brazing or welding a male (externally) threaded flange fitting to each end of the coil. A washer with sealant is then passed over the male thread to sit against the flange. The threaded portion of the fitting is then passed through a hole in the vessel wall so that the flange is adjacent the inside wall of the vessel and a second washer with sealant is placed over the male thread and is tightened up to the outside of the vessel wall by a locknut or backnut. The other end. of the tube is similarly fitted and fixed.

Domestic water storage vessels usually comprise dome-topped copper cylinders which include one or more heating coils for the supply of hot water. To securely mount the heating coils within the storage vessel a hole is cut in either the dome or the side walls of the cylinder. An internally and externally threaded boss is then inserted into the hole together with a split metal washer and a rubber washer to engage the inside wall of the cylinder. A second rubber washer is positioned over the protruding external threaded section of the boss followed by a spacer which is locked down by a retaining nut or backnut. The backnut is then tightened so that flanging elements on the boss bring the metal and rubber washers to bear against the inside wall of the tank and the rubber washer and spacer are brought to bear against the outside wall of the tank. The assembly is then locked into position by tightening the backnut to the 652 correct torque. The heating coils are then passed through f the internally threaded portion of the hollow boss and screwed into position.

Unfortunately, the rubber washers are prone to wear and leaking is common. usually a welded or brazed seal is preferred whereby a flanged boss is welded or brazed to the tank wall. However, the welded or brazed portion usually has a small contact area and due to the repetitive heating and cooling of the tank fractures may occur at weak points around the seal.

It is an object of the present invention to seek to alleviate the above disadvantages and to provide an improved installation arrangement for heat exchange coils in water storage vessels.

Accordingly, the present invention provides a vessel or container having at least one inlet and/or outlet port in which the or each port is an aperture formed in the wall of the vessel, the aperture having a hollow fitting or tube penetrating therethrough so that a relatively large contact area is provided between at least the vessel wall surrounding the aperture and the fitting or tube, with the vessel wall and fitting or tube being sealingly fixed over said relatively large contact area, whereby a reinforced seal having superior strength characteristics may be established.

An initially small aperture formed in the wall may be ' flared inwardly or outwardly with respect to the vessel wall to provide a relatively large contact area with the fitting or tube. The flared portion of the aperture may be turned so that it lies in contact with the surrounding vessel wall to form a reinforced annular ring around the aperture.

Alternatively, a reinforced annular ring is formed around £ the aperture by a flanged fitting sealingly fixed to the vessel wall. A flanged fitting may also be provided over the annular ring formed by the flared vessel wall to provide a seal area of substantial strength.

The invention further provides a vessel or container having inlet and outlet ports for installing heat exchange coils in which the ports comprise apertures formed in the vessel walls so that each end of the heat exchange coils passes through one of the apertures, a flanged female threaded fitting is sealingly threaded and fixed to each of the tube ends and the flange of each fitting is sealingly fixed to the vessel wall.

The invention will now be described more particularly with reference to the accompanying drawings which show, by wav of example only, two embodiments of installation arrangements for heat exchanging apparatus according to the invention. In the drawings: Figure 1 is a sectional side detailed view of a prior art installation arrangement for heat exchange coils; Figure 2 is a sectional side detailed view of a first embodiment of installation arrangement for heat exchange coils; and Figure 3 is a sectional side detailed view of a second embodiment of installation arrangement for heat exchange coils.

Referring initially to Figure 1, a prior art installation arrangement for heat exchange coils is shown. In this arrangement, the heat exchange coil comprises a tube T having at each end a straight portion which is to be 5 sealingly engaged to a wall of a closed water storage vessel V. Two similarly sized apertures are formed in the walls of the vessel and the coil is placed into the vessel through one of these apertures. Each tube end is welded or brazed into a flanged and externally (male) threaded tubular fitting F.

Each flanged fitting F is provided with a first inner washer Wj coated in a sealant composition which is brought to bear against the inside wall of the vessel V. A second 15 outer washer W2. is passed over the threaded portion of the fitting F and brought to bear against the outside wall of the vessel V. A backnut B is then placed onto the fitting F and tightened to bring the flanged fitting into sealing engagement with the vessel wall.

Figure 2 illustrates a first embodiment of installation arrangement for heat exchange coils. A relatively small aperture is punctured in the wall 10 of a water storage vessel in two places (for an inlet and outlet port). The 25 apertures are subsequently flaired outwardly to form a substantially conical region 12 having an aperture sufficiently large to accommodate the outer diameter of the coil tube ends 15. When each tube end 15 is in position with respect to the conical region 12 of the flared vessel 30 wall 10, the region 12 and tube end 15 abut over a relatively large area so that when the tube end is brazed or welded they form a strong bond. The tube ends, which are internally threaded to accept a male fitting 17, provide a secure seal which is not susceptible to failing.

Referring now to Figure 3 which shows a second embodiment installation arrangement for heat exchange coils. Standard '< inlet and outlet apertures are formed in the wall of the storage vessel 20 to accommodate the heat exchange coil tube 22. A flanged female threaded fitting 25 is secured to the heating coil tube 22 and the flanged portion 26 of the fitting 25 is brought to bear against the outside of the vessel wall 20. The flanged portion 26 provides a relatively large area to be brazed or welded to the wall 20 to ensure a strong bond and efficient seal.

It will be seen that the embodiment described above may be adapted for use where any inlet or outlet port is required in a sealed vessel. It is of particular use to provide an efficient seal for immersion group heating elements used in domestic heating systems.

The arrangements provided in the first and second embodiments can be combined to form a third embodiment of installation arrangement (not shown) in which initially small apertures in a vessel wall are flaired outwardly to form substantially conical regions. These regions are subsequently pressed against the outside of the vessel wall to form an annular ring having an aperture of sufficient diameter to facilitate passing a heating coil tube therethrough. A flanged female threaded fitting is then secured to each heating coil tube end and the flanged portion of the fitting is brazed or welded to the annular ring. The brazed or welded seal forms along both the neck and outer surface of the ring. - β It will of course be understood that the invention is not 1 limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the appended claims.

Claims (5)

1. A vessel or container having at least one inlet and/or outlet port in which the or each port is an aperture formed in the wall of the vessel, the aperture having a hollow fitting or tube penetrating therethrough so that a relatively large contact area is provided between at least the vessel wall surrounding the aperture and the fitting or tube, with the vessel wall and fitting or tube being sealingly fixed over said relatively large contact area, whereby a reinforced seal having superior strength characteristics may be established.

2. A vessel or container having at least one inlet and/or outlet port as claimed in claim 1, in which an initially small aperture subsequently flared inwardly or outwardly with respect to the vessel wall provides a relatively large contact area with the fitting or tube.

3. A vessel or container as claimed in claim 1 or claim 2, in which a reinforced annular ring is formed around the aperture by a flanged fitting sealingly fixed to the vessel wall.

4. A vessel or container having inlet and outlet ports for installing heat exchange coils in which the ports comprise apertures formed in the vessel walls so that each end of the heat exchange coils passes through one of the apertures, a flanged female threaded fitting is sealingly threaded and fixed to each of the tube ends and the flange y of each fitting is sealingly fixed to the vessel wall.

5. A method of forming an inlet and/or outlet port substantially as herein described with reference to Figures 2 and 3 of the accompanying drawings, a vessel or container having at least one port formed by said method or a vessel 5 or container as claimed in any one of the preceding claims.