US 2708896 A
Description (OCR text may contain errors)
M y 24, 1955 M. F. SMITH ETAL 2,708,896
INDICATING PROTECTIVE COVERS FOR PIPE FLANGES AND VALVES Filed May 12, 1954 FIGS 26 I OISTURE RESISTANT COATING cnemcn. \mcu CHANGES TRANSLUCENT COLOR UPON CONTACT MATERIAL WITH ACID OR ALKALI United States Patent INDICATING PROTECTIVE COVERS FOR PIPE FLANGES AND VALVES Millard F. Smith, Westport, and Edwards. Smith, Jr., Darien, Conn.
Application May 12, 1954, Serial No. 429,356
4 Claims. (Cl. 116-114) This invention relates generally to the transmission of fluids through pipes and similar conduits, and more particularly to indicating protective covers for pipe and conduit connections and valves. The invention lies in improved materials used in forming these covers, and reference is made to our earlier Patent No. 2,601,840, granted July 1, 1952, to Millard F. Smith and Edward S. Smith, Jr. for examples of the types of covers to which this invention has application.
The covers taught by this patent, while very effective, have suffered from a disadvantage in that where the same are used in atmospheres which are heavily laden with moisture vapors, there has been a tendency for the chemical substance with which the fabric lining is impregnated to be affected by small amounts of alkali or acid present in the vapors, so that with passage of time, the covers would give the impression of overlying a leaking or damaged joint, when in fact the joint is in undamaged condition. Such indication has caused the removal of the cove-r and useless checking of the condition of the joints therebeneath, and the replacement of a fresh or unaflected cover with consequent waste of time.
It is therefore among the principal objects of the present invention to provide structure in the form of improved material employed in the construction pipe flange and valve, covers in which the above-described disadvantages have been substantially eliminated.
Another object of the invention lies in the provision of improved cover structure which may remain impervious to the effects of moisture and vapor laden air containing small amounts of acid or alkali, but will readily indicate the presence of a strong alkali or acid leaking from covered pipe flange joints.
Another object of the invention lies in the provision of pipe flange cover material possessing the above advantages, in which the cost of fabrication may be of a reasonably low order, with consequent wide sale, distribution and use.
A further object of the invention lies in the provision of cover material which may be readily and easily inspected as has been the case in the prior art, and which may be fully as flexible and durable as the material is used in construction known in the prior art.
A feature of the invention lies in the fact that the material may be produced at a cost closely approximating that found in the manufacture of prior art materials.
These objects and features, as well as other incidental ends and advantages, will become more fully apparent in the progress of the following disclosure, and be pointed out in the appended claims.
On the drawings, to which reference will be made in the specification, similar reference characters have been employed to designate corresponding parts throughout the several views.
Figure l is a view in perspective of an indicating cover embodying the invention in place upon a pipe flange structure of the covers 12 and 14 is of a type fully described in the above-mentioned Patent No. 2,601,840, the lines of interconnection 18 being engaged by stitch means 20, or the like.
Referring to Figure 4 of the drawing, the laminated material 10 includes a woven textile layer 22, an outer transparent or translucent impervious layer 24, and an inner protective layer or coating 26.
The fabric layer 22 is preferably formed from woven fiberglass or other inert textile material, although where considerations of cost are involved, the same may be formed from conventional canvas and the like. The layer 22 is impregnated with suitable chemicals depending upon the alkalinity or acidity of the potential leakage. Examples of such naterial are phenolphthalein, methyl red, methyl orange, litmus, thymol blue, and similar materials.
The outer impervious coating 24 is preferably formed from transparent vinyl material which may be applied as a coating, or as a thin sheet fused to the fabric layer 22 by heat sealing or other suitable means. It is desirable that this material be either colorless or of a translucent white color, so that the effects of the impregnated chemical may be easily viewed upon inspection through the same.
The inner moisture resistant coating 26 may be in the form of glue, varnish or similar materials which are essentially water resistant, but which are readily attacked by acids or caustics in water or liquid solution. This coating is preferably applied after the integration of the layers 20 and 22, so that the same is not subjected to heat or heating processes during or after application.
In use, the material is so placed that the coating 26 is adjacent the pipe flange or valve, and the impervious layer 24 is disposed outwardly. During normal operation, the center fabric layer 22 is completely enclosedand protected from the effects of the ambient air by the impervious layer 24 on the outside and the moisture resistant layer or coating 26 on the inside. Should this air contain an appreciable amount of acid or alkali, the vapor suspension of the same is normally unable to penetrate either layer or coating, and upon inspection the cover shows no leakage. Should actual leakage occur from the valve or joint in question, the liquid solution or suspension of the acids or caustics will attack the glue or varnish coating 26, and in a relatively short time the coating will be penetrated to permit the acid or caustic or reach the fabric layer 22, thereby afiecting the impregnated chemical. Since the central layer is of woven or similar material, a wicking action ocurs which causes the caustic or acid to be drawn into the fabric layer, thereby causing indicating color to appear in the same over an area substantially larger than the penetrated opening in the water resistant layer 26. Thus, once any penetration is accomplished, the inspecting party is quick to discern a leakage, so that prompt action may be taken.
If desired, coatings other than glue or varnish may be employed provided the same are relatively impervious to water or moisture, and are quickly affected by the pressure of strong acid or alkaline solutions.
It may thus be seen that we have invented new and useful improvements in materials for forming indicating protective covers for pipe flanges, valves and similar devices, in which provision has been made for making the indicating chemical or material relatively impervious to ambient vapors, and nevertheless readily affected by the presence of substantial amounts of acids or alkalis carried by the joints 01 valves covered. The cover material may be manufactured using techniques known and existing in the art, and at a cost very slightly higher than that reached in the manufacture of conventional cover mate rials. Where extreme economy is desired, the central fabric layer may be eliminated, and the indicating material coated directly to the outer impervious layer, and covered by the resistant coating in a manner suggested in the above-mentioned Patent No. 2,601,840. I
We wish it to be understood that we do not consider the invention limited to the exact details of structure shown and set forth in the specification, for obvious modifications will occur to those skilled lin the art to which the present invention pertains.
1. Material for forming protective indicating cover structure comprising: a first Woven fabric layer impregnated with an indicating material; a moisture resistant structure comprising: a first woven fabric layer impregnated with an indicating material; a moisture resistant coating soluble in acid superposing said layer; and a translucent impervious layer on the side opposite said moisture resistant coating.
4. Material for forming protective indicating cover structure comprising: a first woven fabric layer impregnated with an indicating material; a moisture resistant coating soluble in alkali superposing said layer; and a translucent impervious layer on the side opposite said moisture resistant coating.
References Cited in the file of this patent UNITED STATES PATENTS Snelling July 22, 1941 Smith July 1, 1952