US3319657A - Coil freeze protection device - Google Patents

Description

May 16, 1967 A. NYIRI COIL FREEZE PROTECTION DEVICE Filed Oct. 16, 1964 INVENTOR Laws 1. A/yw'o United States Patent 3,319,657 COIL FREEZE PROTECTION DEVICE Louis A. Nyiri, 120 N. Fairview St.,

Lock Haven, Pa. 17745 Filed Oct. 16, 1964, Ser. No. 404,295 1 Claim. (Cl. 13827) This invention pertains to heat exchange coils and more particularly to relief plugs for preventing damage when the fluid within a serpentine heat exchange coil freezes.

An object of the invention is to prevent damage to a heat exchange coil in the event the fluid within the coil freezes.

A further object is to provide a relief plug which will relieve stress created by a freeze-up within the coil.

A further object is to place a relief plug at the bends of a serpentine coil to effectively relieve pressure caused by a freeze-up beginning in the straight sections of the coil.

Further purposes appear in the specification and in the claim.

In a heat exchange coil of a type which may be used for either heating or cooling, a fluid or vapor normally passes within a serpentine arrangement of tubing. Such liquids or vapors may be, for instance, in the case of a heating system, hot water or steam, or in the case of refrigeration, any of the well known refrigerants such as Freon. The serpentine tubing normally consists of straight sections and U-shaped end sections connected to two of the adjacent straight sections.

When used for heating, hot water or steam passes through the interior of the coil and air to be heated is blown over the exterior. The air is usually coming from a colder source, such as the exterior of a building, and there is a chilling effect on the coil. Sometimes the fluid within the coil freezes and causes the coil to burst. In a cooling coil, the refrigerant may likewise freeze under improper conditions causing damage to the coil.

Efforts have been made to relieve or to prevent such damage from freezing. In one form of protection against freezing used in the prior art, a temperature sensing device acts responsive to the temperature of the air which has been passed over the coil. When such air drops below a certain temperature, for instance, 36 or 38 degrees Fahrenheit, the device will close an outside air damper which prevents air from passing through the exchanger. The device can additionally open a control valve in the coils to allow full flow through the coil, and it can additionally shut down the fan motor blowing air across the coil. In spite of such precaution, however, coils still freeze and burst.

In the present invention, it has been found that freezing takes place in the coils in the center part of the straight sections and travels to the end connections or U connections. It has been further found that by relieving the pressure at the bend of the coil, damage to the coil from freezing can be prevented.

The present invention does not attempt to prevent freezing in a serpentine coil but rather prevents damage to the system when freezing occurs. This is done by providing relief plugs in the bends of the coil. The relief plug is secured in a housing which is desirably integral with the coil itself. The plug includes a plug body which holds a disc that, in the event of freezing, is forced out of the plug body and relief is allowed for the expanding solid, for instance, ice. Hence, there is no damage to the coil itself and the relief plug or disc can be readily replaced.

In the drawings I have chosen to illustrate a few only of the numerous embodiments in which the invention may appear, selecting the forms shown from the standpoints of convenience in illustration, satisfactory opera- 3,319,657 Patented May 16, 1967 ICC tion, and clear demonstration of the principles involved.

FIGURE 1 is a fragmentary front elevational view of a typical serpentine coil showing several embodiments of the invention.

FIGURE 2 is a fragmentary vertical sectional view of the relief plug of FIGURE 1.

FIGURE 3 is an end elevation of the relief plug of FIGURE 2.

FIGURE 4 is a vertical section of an alternate embodiment of a relief plug.

FIGURE 5 is a sectional view of an alternate embodiment of a relief plug.

Describing in illustration but not in limitation and referring to the drawings:

As seen in FIGURE 1, a serpentine coil 20 of tubular construction has straight sections 22, 24, 26 and 28 and U-bends 30, 32 and 34 joining the adjacent straight sections. The coil '20 may be formed of any suitable material, such as copper, which has a sufliciently high rate of thermal conductivity to readily permit a heat exchange through the tubing. It will be understood that only a portion of a coil is shown, and that the coil may permissibly have any number of bends and may be of any size and proportion.

The U-bends are suitably connected, as by soldering, at joints 36, 38, 40, 42, 44 and 46. These joints can be of a type having a flared section 48 on the U which receives therein the end of the straight section, with solder connecting and holding fast the flare and the portion of the straight tube within the flare, where the tubing is of, for instance, copper.

The relief means of the invention may be applied to the coil in a variety of embodiments. In one embodiment as shown at 50 in U-bend 30 as seen in FIGURE 1, housing 52 is integrally connected to the U connection and includes a tubular portion 54 which is in line with straight section 22. The main portion of the housing 52 comprises a portion 56 which has suitably located therein internal threads 58.

Plug body 60, having threads 62, is screwed into housing portion 56. The plug additionally includes a disc 64 which engages in cut-out portion 66 of the plug body 60 by means of, for instance, a shrink fit which can be achieved by expanding the plug body 60 by heat means, inserting the disc within the plug body in the cut-out portion 66, and then allowing the plug body 60 to cool, thus securely holding the disc.

The housing 52 along with the plug body 60 and disc 64 may be positioned alternatively at the base or bend of the U-bend as shown in its installation in the U-bend 32 at 70. In this embodiment, the tubular portion 54 is formed into the bend at a point intermediate the straight sections 24 and 26.

In another form, as shown in the U-bend 34 in FIG- URE l, housings for the plugs are formed at 74 and 76 which are extensions of the straight sections 26 and 28. The form of these plugs is the same as that shown at 50 in FIGURE 1.

Alternative fonms of plugs are shown in FIGURES 4 and 5. In FIGURE 4, a housing 80 in the form of a sleeve has a tubular portion 82 and a flared portion 84. The tubular port-ion 82 is joined by soldering or the like to section 86 which extends from U-bend 88. The flared portion 84 supports therein a disc 90 having a skirt 92. The skirt 92 is held in the sleeve by means of a shrink or force fit.

In the form shown in FIGURE 5, the relief plug is in the form of a body 94 having a portion 96 ending in a flat face 98. A smooth flat disc 100 is secured to the face by means of an adhesive or cohesive type material which will break under a predetermined pressure. The

3 body has a tubular portion 102 which is secured to extension 194 of U-bend 106. V

In operation, the coil is assembled with any of the plugs as shown installed in the U-bends of the coil. In the event the fluid Within the coil begins freezing, a solid begins forming in the straight. sections 22, 24 and 26 at generally the centers thereof and moves progressively towars the bends. As long as there is space for the solid, formed by freezing, to expand in any direction, no damage to the coil tubing occurs. When the freezing action of the fluid into a solid progresses to the U-bends, there is no more space for expansion. However, the action of the expanding, freezing, fluid forces the disc 64 out of the plug body 60, thus relieving the pressure Within the coil 20 without damage to the coil itself. The plug can then be readily replaced with a replacement plug or a replacement disc.

In view' of my invention and disclosure, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claim.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

In a heat exchange coil ,of serpentine form having straight sections and U-bends connecting the straight sections, relief means'in the U bends for relieving pressure caused by fluid within the coil freezing into a solid comprising a housing mounted in the U-bend and communicating Withthe interior of the coil and a plug supported by the housing having a plug body held by the housing and a disc in the plug body adapted to be separated from the plug body by the pressure of the freezing solid.

References Cited by the Examiner UNITED STATES PATENTS 1,159,225 11/191-5 Howell 13827 FOREIGN PATENTS 560,612 4/194'4 Great Britain.

LAVERNE D. GEIGER, Primary Examiner.

C. L. HOUCK, Assistant Examiner.

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