US2924973A - Gauge for oil tank - Google Patents

Description

Feb. 16, 1960 H. J. ca. RUDOLF GAUGE FOR OIL TANK Filed July 2, 1956 Brookline, Mass., as'signor to Applied g a corporation of Massa- This invention relates to gauges for tanks for liquids, 'and more particularly for oil tanks such as are commonly used to hold a supply of fuel oil for a house-heating burner. It is an object of. the invention to provide a gauge whichv is simple, inexpensive to make, reasonably :accurate, and capable of being compactly packed for shipment.

According to the invention. a vertically slidable indicator is mounted on a column or post rising from a screw plug which is screwed into a filling hole in the tank. A light spring is arranged to draw the indicator slide upward. A light-weight strand or chain dangles from the indicator-slide through a hole in the plug. To the lower end of the strand or chain'is secured a flexible elongated member which may have a specific gravity only slightly "greater than that of the liquid'in' which it dangles, or may have a considerably higher specific gravity. Inthe latter case, the other end thereof is attached to and supported by a suitable float as hereinafter explained.

For a more complete understanding of the invention, reference may be had to the following. description thereof,.- and to the drawing, of which-- Figure 1 is an elevational view of a device embodying the invention;

.'Figure 2 is an elevation of a guide strip and indicator slide, and a modified form of pendant attached to the slide;

Figure 3 is an elevation of a screw plug and post to carry the guide strip and indicator slide;

Figure 4 is a plan view of the guide strip;

Figure 5 is a perspective view of the indicator slide;

Figure 6 is a section of the post with other parts assembled thereon;

Figure 7 is a sectional view of an oil tank on which the device shown in Figure 1 is installed;

Figure 8 is a sectional view of a tank with a gauge having the form of pendant shown in Figure 2; and

Figure 9 is an elevation of another modified form of pendant.

While the invention is applicable to tanks and liquids of various kinds, the embodiments hereinafter described are designed for use in gauging the depth of the pool of oil in the type of closed tank customarily used in dwellings for supplying oil to the burner in a heating unit. Such a tank is illustrated at 10 in Figures 7 and 8. Each such tank has a hole in the top thereof which is screwthreaded to receive a gauge. According to the invention, an improved gauge is provided which comprises a screw threaded plug 12 serving as a base or support member for the rest of the gauging mechanism. The plug 12 has a central aperture in which is secured the lower end of an upright post 14. This post is in the form of a split tube having a vertical slot 16 extending from end to end. Mounted on the post 14 is an assembly of parts as illustrated in Figure 2, consisting of a front guide strip 18, an indicator member which includes an index 20, a spring 22 and an elongated connecting element 24. The upper end of the vertical-guide strip 18 States Patent "ice is bent to a horizontal plane and is in the form of a disk 26 which fits in the top of' the split tube 14 and is com nected to the vertical portion of the strip 18 by a neck 28 Which is slightly wider than the slot 16 of the post.

When theparts are assembled as indicated in Figure 6, "the side edges of the neck-ZUcngage in notches 30 in the edges of the slot 16 and hold the guide strip in front of the 'slot 16 and parallel to the axis of the post. Notches 32 are provided in the disk 26 to receive a loop of the spring 22 atthe upperend thereof.

The indicator member is made of one piece of sheet metal such as aluminum. 'lt 'has a vertical shank 34 from the lower end of which a disk 36 projects horizontally to ride within the split tube 14. The disk 36 has notches 38 in its edges'to receive a loop of the spring 22 at the lower end thereof. The tension spring'22 thus extends from the disk 26 of the fixed guide strip to the disk 36 of the movable indicator member and tends to move the latter upward. At the upper end of the shank 34 of the indicator member is a wider portion 39 which is bent over with an aperture lfl-through which the guide strip 18 passes. The extremity of the bent-over portion of the indicator member is the index 20. The disk 36 at the lower end of the indicator member has a deep slot 42 to receive the upper end of the flexible line 24 to attach the line to the indicator member. The flexible member may be of any suitable material which is relatively light in weight. For example, a light variety of chain of the type used for chain-pull light" sockets may be employed. ThlS' line extends from the indicator member down within the split tube 14, through the aperture in the plug 12 and into the interior of the tank '10.

vfloat 46. The lengthof the chain 44 is approximately equal to half the depth of the pool in the tank when the tank is filled to the prescribed full-tank level with liquid such as oil. The combined length of the line 24 and chain 44 is just enough to suspend the float clear of the bottom of the tank when the tank is empty. Under such circumstances the entire weight of the line 24, chain 44 and float 46 depends from the indicator member and the gravitational pull of these parts stretches the coiled spring 22 so that the index is at its empty-tank position. When liquid is put into the tank, it picks up the float and as the level rises an increasing portion of the chain 44 is supported by the float instead of the spring 22. As the gravitational pull on the spring is thus diminished, the spring contracts and elevates the indicator member until the index 20 reaches the full-tank position when the tank has been filled. When this occurs, the entire weight of the chain 44 is carried by the float 46 and the liquid in which the chain is immersed. The only gravitational pull then acting on the spring is that due to its own weight and that of the light flexible line 24, both of which are negligible. Hence, when the tank is full there is little or no elongation of the spring and the indicator is as near to the top of the gauge casing as it is possible to get, and substantially the full height of the casing is available for the scale marks. The scale divisions between the full and empty marks are therefore of maximum size which is desirable for easy reading.

An desired scale may be provided to cooperate with the index to indicate the contents of the tank. For example a closed-end tube 50 of transparent material such as lucite may be mounted on the plug 12 to enclose and protect the post 14 and the parts thereby. The index 20 is visible through the wall of the tube on which suitable indicia 52 may be placed as scale markings.

Another embodiment of the invention is illustrated in Figures 2 and 8. Instead of a chain with a float to support it when the liquid level is high, a flexible strip" 60 of material is suspended from the line 24 to dangle vertically in the tank. This material should have a speeific gravity a little greater than that of the liquid in the tank so that the strip'will hang verticallywhether the tank is empty or 'full; For use he domestic oil-supply tank, the'strip-60 may be madejof ground-cork mixed with a suitable synthetic resin which-is imprevious to the kind of oil which is to be put into the,tank. For this purpose a butadiene-acrylonitrile copolymer well-known by the name of Buna N is'suitable. A mixture of this resin with ground cork, having a specific gravity from 0.95 to 1.05 is. available in the market. As the specific gravity of domestic fuel oil is about 0.8, a strip or strap ofthe material described will hang vertically in-air or oil and can be readily coiledv into a small compass for packing or shipping. The length of the strip 60 is such that when suspended in an'empty tank it will extend from near the top-of the tank almost to the bottom thereof. The index will then be opposite the empty mark. As the tank is being filled with oil, an increasing part of the strip will be partially buoyed by the oil so that there will be a decreasing gravitational pull on the indicator member. When the tank is full, a maximum amountof the strip 60 is immersed in and partially buoyed by the oil, and the index 20' is at the full-tank mark. In this form also of the invention the line 24 is selected to have negligible weight so that when the tank is full of liquid, the pull on the spring spring coil and substantially the full casing is utilized for the scale.

l ,The dangling member 60 which displaces a varying amount of liquid according to the depth of the pool in the tank may be made'in other forms. For example a flexible string of hollow beads 62 suitably linked together may be employed, the beads being of metal or other relatively heavy material which with the hollow interiors will average the desired specific gravity.

I claim:

1. A tank gauge comprising a support member height of the gauge 22 is not enough to elongate the adapted to be mounted over a tank, an indicator member supported bysaid support member and movable thereon from a full-tank position to any empty-tank position, spring means carried by said support tending to move said indicator toward the full-tank position, a flexible line of negligible weight depending from said indicator, a heavier chain attached to and depending from said flexible line, and a float attached to the free end of said chain, the combined length of the flexible line and chain being such as to suspend the float almost in contact with the bottom of the tank when the device is mounted over an empty tank, the length of the chain alone being approximately half the depth of the liquid in the tank when the tank is full.=

2. A tank gauge comprising a support member adapted to be mounted over a tank, an indicator member supported by said support member and movable thereon from a full-tank position to an empty-tank position, a tension spring secured at its upper end to said support member and at its lower end to said-indicator member, a flexible line of negligible weight depending from said indicator and extending approximately half way to the bottom of the tank when the gauge is mounted in place, a heavier chain attached to and depending. from the lower end .of said line, and a float attached to the free end of said chain, the length of said chain from the line to the float being approximately half the height ofthe tank.

References Cited in the file of this patent UNITED STATES PATENTS 706,505 IWashington Aug. 5, 1902 2,029,405 Beadle Feb. 4, 1936 2,096,411 St. John et al. Oct. 19, 1937 FOREIGN PATENTS 6,936 Great Britain May 8, 1915 598.867 Great Britain Feb. 27, 1948

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