US2749929A

US2749929A - Tank bleeding device

Info

Publication number: US2749929A
Authority: US
Publication date: 1956-06-12
Anticipated expiration: 1973-06-12

Description

June 12, 1956 E. CRQW TANK BLEEDING DEVICE 2 Sheets-Sheet 2 Filed Sept. 29, 1952 dmas 5: 'razd 49 United States Patent TANK BLEEDING DEVICE Amos E. Crow, Long Beach, Calif.

Application September 29, 1952, Serial No. 312,055

14 Claims. (Cl. 137172) The present invention relates generally to the storage of liquids in tanks, and more particularly to a novel tank bleeding device for use with liquid storage tanks.

Liquid storage tanks are widely used throughout the world today. In many instances it is necessary to store a plurality of liquids having different specific gravities in a single storage tank whereby such liquids will assume separate horizontal stratums. Common examples occur where oil or gasoline is stored in a tank together with water, which water may have entered the tank with the oil or gasoline, or perhaps later entered the tank by means of leakage or condensation. Inasmuch as such water will have a lower specific gravity than the oil or gasoline, it will settle to the lower part of the tank and form a strata. Thereafter, at such time as it becomes desirable to remove the oil or gasoline from the tank, this strata of water must be bled off whereafter substantially uncontaminated oil or gasoline will remain for withdrawal.

Commonly, when the water bleeding process is taking place it is necessary to post an operator adjacent the tank in order that he may close the tank outlet the moment the water has been bled therefrom. This is necessary in order to prevent the waste of the oil or gasoline remaining in the tank after the water has been bled off. This arrangement is unsatisfactory inasmuch as it requires that an operator remain in the vicinity of the tank for what may amount to a considerable period of time whereby he is unable to attend to other duties. Furthermore, this arrangement is subject to human frailties on the part of the operator, and it often occurs that through his inattention -a large amount of the valuable oil or gasoline may be bled off with the water.

It is a major object of the present invention to provide a novel tank bleeding device having means for automatically shutting off the flow of liquid from the tank at such time as the water has been bled therefrom.

It is another object of the present invention to provide a novel tank bleeding device having automatic shutoff means sensitive to both the specific gravity and the viscosity of the liquid being bled from the storage tank. Such dual sensitivity is essential inasmuch as it often occurs where a heavy oil is being stored, that such heavy oil may have a specific gravity of a value close to specific gravity of water, or alternately, where a gasoline is being stored such gasoline may have a viscosity which is similar to the viscosity of water. Under these conditions, if a single tank bleeding device is to be utilized it is essential that its automatic shut-off control be sensitive not only to specific gravity but also to viscosity.

A further object of the present invention is to provide a tank bleeding device for storage tanks which is simple of design and rugged of construction whereby it may have a long and trouble-free service life.

An additional object of the present invention is to provide a tank bleeding device for storage tanks which permits a tank to be bled in a minimum amount of time and with aminimum amount of turbulence.

2,749,929 Patented June 12, 1956 It is a yet further object of the present invention to provide a tank bleeding device for storage tanks which has a novel arrangement for returning any liquid of a lower specific gravity than that being bled off which inadvertently enters the device, whereby such liquidmay return to the main body of such lighter liquid.

Another object of the present invention is to'provide a tank bleeding device which may be incorporated within existing liquid storage tanks without extensive modification thereto.

Another object of the present invention is to provide .a tank bleeding device which will at all times be under the complete control of an operator stationed externally of such storage tank.

Other objects and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the appended drawings wherein:

Figure 1 is a side elevational view showing a tank bleeding device embodying the present invention mounted within a conventional liquid storage tank;

Figure 2 is an enlarged top plan view of the tank bleeding device shown in Figure 1;

Figure 3 is a front view showing a bank of hand controls which may be employed with a tank bleeding device embodying the present invention;

Figure 4 is a horizontal sectional view taken along lines 44 of Figure 3;

Figure 5 is an enlarged vertical sectional view taken on lines 55 of Figure 2;

Figure 6 is a fragmentary horizontal sectional view taken on lines 6-6 of Figure 5;

Figure 7 is a horizontal sectional View taken on lines 7-7 of Figure 5.

Referring to the drawings, and particularly to Figure 1 thereof, there is shown a liquid storage tank, generally designated 10, adapted to hold liquids of different specific gravities, as for example, oil and water or gasoline and water. The water within the tank 10 will be disposed in a strata extending upwardly from the bottom of the tank with the oil or gasoline being disposed between the top of the water strata and the upper portion (not shown) of the tank. A novel tank bleeding device embodying the present invention and generally designated B, is shown mounted within the confines of the tank whereby it may bleed off the strata of water disposed in the lower portion of the tank. During this bleeding process such water will enter the device B through an inlet 12, as indicated by the arrows. The device B is in communication with the exterior of the tank by means of a horizontal pipe 14 which extends outwardly from the device through one side of the tank. Operation of the tank bleeding device B may be effected through a set of hand controls 16 which are connected to the device B through a second pipe 18.

Referring to Figure 5 forthe general arrangement of a preferred form of tank bleeding device B, it will be seen that this devices includes a main body 20 which is composed of an upper cylinder 22, an intermediate cylinder 24, and a lower cylinder 26. The lower end of the cylinder 26 is seen to mount a frusto-conical collector ring 28 into which flows liquid from the bottom of the tank, as indicated by the arrows. Such liquid flows upwardly through an orifice 3% formed in an orifice plate 32. After flowing through the orifice 30, this liquid is free to pass through an outlet 34 into the outlet pipe '14. Flow of liquid through the orifice 30 is adapted to be controlled by a stopper 36, which stopper is vertically movable relative to the orifice. Movement of this stopper 36 is controllable by means of a float 38 and by a viscositysensing device 40, in a manner to be fully set forth hereinafter. In general, however, the movement of this 3 stopper 36 is controlled in such a manner that it normally will remain open while water is being bled from the bottom of the tank 10. At such time as oil or gasoline commences to flow through orifice 30, either the float 38 or the viscosity-sensing means 40 will at once and automatically cause the stopper 36 to be moved upwardly so as to block the flow of liquid through the orifice 30.

With more particular regard to the details of construction of the preferred form of tank bleeding device B, the device is seen to be moved upwardly so as to block the flow of liquid through the orifice 30.

With more particular regard to the details of construction of the preferred form of tank bleeding device B, the device is seen to be supported on a base plate 42, which plate at its outer peripheral portion mounts the lower end of a plurality of vertical spacer bars 44. The plate may also mount a rubber-like ring 45. The spacer bars 44 are held in place by means of vertical bolts 46 and nuts 48. Disposed between the tops of the spacer bars 44 and the nuts 46 is a cylindrical turburlence shield 50 having an upper portion 52 which is frusto-conical in configuration and includes a plurality of bores 54. The bores 54 serve to release any oil or gasoline which enters within the turbulence shield during the bleeding of water from the bottom portion of the tank. Such oil or gasoline as enters with the water will rise to the upper interior portion of the turbulence shield 50, inasmuch as it will be lighter than the water. From this upper portion such oil or gasoline may pass upwardly through the bores 54 to the main body of oil or gasoline disposed above the turbulence shield.

The upper portion 52 of the turbulence shield is coaxially formed with a bore 55 having a slightly larger diameter than that of the lower cylinder 26. Radially outwardly of this bore 55 are formed a plurality of apertures for receiving bolt and nut combinations 56, which combinations serve to rigidly interconnect the turbulence shield and a support plate 58. The support plate 58 mounts the upper end of' the lower cylinder 26, as Well as the orifice plate 32, by means of a plurality of bolts 60. The lower end of the intermediate cylinder 24 is shown as being welded to the upper surface of the support plate 58.

The float 38 is preferably of annular configuration having a central opening 62 of greater diameter than the outer diameter of the lower cylinder 26. The upper and lower sides of the float are seen to be sloped similarly to the slopes of the sides of the collector ring 28 and the upper portion 52 of the turbulence shield 50. A rubberlike sleeve 64 is mounted between the upper end of the float 38 and the lower surface of the support plate 58 whereby will be trapped any oil or gasoline which rises to the upper portion of the turbulence shield 50. The inner portion of the float 38 rigidly mounts a plurality of downwardly extending guide bars 66. These bars are seen to have a sliding relationship with a plurality of bores 68 formed in the lower flanged end of the lower cylinder 26 and the upper ends of the collector ring 28. The lower ends of the guide bars are bolted to a spider 70, the central portion of this spider being shown disposed between a pair of

collars

71 and 72 mounted by the lower end of a vertical rod 74. The rod 74 is by this arrangement free to rotate relative to the spider 70. The lower end of this rod is centrally bored at 76 whereby it may have a sliding engagement with an upstanding guide pin 78 rigidly mounted by the center of e the base plate 42. Thus, the float 38 and the rod 74 are seen to be interconnected for simultaneous vertical movement relative to the base plate 42 and its rigidly mounted components.

The upper end of the intermediate cylinder 24 includes an outwardly extending flange 79, which flange is adapted to be rigidly connected to a similar flange 80 formed on the lower end of the upper sleeve 22 by a plurality of bolts 81. These bolts 81 also serve to rigidly secure a horizontal blocking plate 82 between these flanges. Co-

axially disposed within the bore 84 of the blocking plate 82 is a first sleeve 86 whereon is rigidly mounted at its lower end the stopper 36. A resilient sealing ring 88 serves to seal the outer periphery of the first sleeve 86 relative to the upper cylinder 22. Coaxially disposed between the rod 74 and the first sleeve 86 is a second sleeve 90. It should be observed that the rod 74 and this second sleeve 90 are interconnected by means of a pin 92 adapted to slide within a slot 94 formed in the rod. With this arrangement, the rod 74 and the second sleeve 90 are adapted for relative longitudinal and rotational movements for a purpose to be set forth hereinafter.

It should also be noted that the float 38 and stopper 36 are so interconnected that vertical movement of the float in one direction will effect simultaneous vertical movement of the topper in the opposite direction. To this end, the mid-portion of the rod 74 pivotally mounts a cross arm 96. The outer ends of this cross arm 96 are pivotally connected to the lower end of an upper arm 98 and an upper end of a lower arm 100. The upper end of the upper arm 98 is pivotally connected to a stationary slider box 102, which slider box is fixedly supported within the upper cylinder 22. The lower end of the lower arm 100 in turn is pivotally connected to the upper end of the first sleeve 86. In this manner the aforementioned arrangement between the float and stopper may be accomplished. In Figure 5 the float 38 is shown in a raised position whereby the stopper 36 is concurrently disposed in a lowered position relative to the orifice 30 in order that fluid may flow through this orifice.

In order to facilitate movement of the float and stopper into a closed position they may mount rubber-like sealing cups 101 and 103, respectively, each having projecting lips for making initial contact. Although the viscositysensing means may assume various forms, the preferred manner of construction comprises a pair of

horizontal discs

104 and 106. These discs will be formed with a plurality of segmental apertures 108 extending inwardly from the discs peripheries, as shown in Figure 7. The disc 104 is seen to be rigidly mounted at the lower end of the stopper 36. The other disc 106 is rigidly mounted by the lower end of the second sleeve 90. A pair of sealing rings 110 and 112 are provided to effect sealing between the stopper 36, second sleeve 90, and rod 74. With this arrangement, the two

discs

104 and 106 cooperate to urge the stopper 36 upwardly into the orifice 30 whenever the eifective combined area of the discs is exposed to liquid having a predetermined viscosity moving at a predetermined velocity. The effective combined area of these discs may be varied by their relative rotation, as will be clear by reference to Figure 7. Thus, where these discs are disposed with their apertures 108 ofiset so as to present an area exposed to upwardly flowing liquid of the entire surface of a non-apertured disc, the effective combined areas of the discs will be at a maximum. In this case, the stopper 36 will be urged upwardly upon the passage past the discs of a liquid having a minimum viscosity and moving at a given velocity. If, on the other hand, where the discs are disposed with their apertures 108 in vertical alignment, it will require the passage past the discs of a liquid having a maximum viscosity and moving at the same given velocity in order to effect upward movement of the stopper. The relative rotational relationship of the two discs may be varied in a manner to be fully set forth hereinafter.

Referring now to the general mode of operation of the tank bleeding device B, at such time as a liquid storage tank containing for example, oil and water, is to be bled of its water content, the stopper 36 will be maintained in its position shown in Figure 5. This will be true since the float 38 will be disposed in its uppermost raised position at such time as it is submerged in the water strata situated at the bottom of the storage tank. At such time, however, as this water strata is bled off through the out- '5 let pipe 14, the, float 38 will be surrounded by the oil originally located above the water strata. At this time, if the float has been properly adjusted, its buoyancy will decrease because of the lower specific gravity of the oil as compared to the water. As the fioat thus lowers, the stopper 36 will be raised so as to cause it to block the flow through the orifice 30. Assuming, however, that the oil contained within the storage tank is of a specific gravity similar to that of water, it will be necessary to effect cut-off of the bleeding operation by means other than the float 38. To this end, there has been provided the viscosity-sensing means 40; it being understood that the oil will have a different viscosity than water. This is especially the case where a heavy oil is concerned, inasmuch as itis the heavy oil which in general has a specific gravity approximating that of Water. Thus, assuming that the

discs

104 and 106 have been adjusted so as to present an effective combined area adequate to effect upward movement of the stopper 36 upon exposure to a liquid having the viscosity of heavy oil, once such heavy oil reaches these discs the stopper will be urged upwardly so as to cut off the flow of liquid through the orifice 3t). Should the liquid storage tank contain gasoline and water, rather than oil and water, it will be apparent that the viscosity-sensing means 40 would have little .or no effect on closing the stopper 36. This is true inasmuch as the anisms could be provided for such purposes, the preferred form of mechanisms are disclosed in the drawings.

. Thus, with particular reference to Figures'S and 6, it will be seen that the rod 74 includes at its upper end a rack element 114'. The teeth of this rack element are meshed with the teeth of a pinion 116, which pinion is rigidly affixed to a horizontal shaft 118 rotatably mounted by a support block 120. The support block 120 is carried by the upper cylinder 22. The shaft 118 also rigidly mounts an arm 122 bearing a weight 124 spaced horizontally from the pinion 116. With this arrangement it will be seen that the weight 124 constantly biases the rod 74 upwardly whereby the float 38' will be concurrently biased downwardly. The weight 124 thus serves to counterbalance the lifting force of the float. The effectiveness of this weight 124 as a counter-weight will be controlled by the angle the weight and its arm 122 make with the horizontal; the weight exerting the major amount of biasing force at such time as the arm 122 is disposed parallel to the ground. The angular position of the weight 124 and its arm 122 is adapted to be controlled by the relative position of the support block 120 with respect to the upper cylinder 22. Vertical-movement of the support block 120 relative to the cylinder 22 may be -effected by means of the control rod 126. This rod is seen to be pivotally connected at its inner end to the upper end of an arm 128. The lower end of this arm 128 is in turn pivotally connected to the side of the support -block 120.

Accordingly, rotation of the control rod 126 by means of its handle 130 will effect vertical movement of the support block 12%) relative to the sleeve 22 and the rack 114. The support block will-be guided in its vertical movement by means of bolt 132 disposed in slots 134formed at the upper and lower ends of the support block.

The relative disposition ofthe discs 1M and 106 comprising the viscosity-sensing means 44), is adapted to be controlled by the rotation of the lower disc 106 relative to the upper disc 1M. Rotation of the lower ,disc 166 .of the sleeve 86 and stopper 36.

is effected by rotation of the .second sleeve 0. The rotation of the sleeve 90 is in turn effected by rotation of the rod 74 and it is to this end that the rod and sleeve are interconnected by means of the pin 92 which rides in the slot 94. Rotation of the rod 74 is controlled by means of the control rod 136 having the handle 138. The upper end of the rod 74 and the control rod 136 are interconnected by means of a guide member 140 mounting at its upper end a pivot arm 142 and a segmental pinion 144 rigidly secured to the inner end of the control rod 136; the outer ends of the pivot arms being formed with teeth meshed with the teeth of the pinion 144. The upper end of guide member 140 is seen to be rotatably carried within a hub 146 coaXially mounted by an upper closure element 148 for the cylinder 22. This guide member 14th is formed with a vertical bore 150 wherein is slidably received the circular rack 114. A pin 15 2 disposed within a slot 154 formed in the guide member Mt? serves to interconnect the rack 114 and the guide member for relative vertical longitudinal movement; said rack and guide member being keyed against relative rotational movement. With this arrangement, at such time as the handle 133 and control rod are rotated, the guide member 140, rod 74, and lower disc 1&6 will be simultaneously rotated so as to vary the vertical alignment of the discs apertures 108.

The present invention also contemplates the provision of control means effective to operate the stopper 36 independently of the float 38 or the viscosity-sensing means 40. To this end, the upper end of the first sleeve 86 is shown connected to the lower end of a vertical link 156. The upper end of the link 156 is connected to an intermediate link 158 by means of a bolt 16!). The upper end of the intermediate link 158 is in turn shown pivotally connected to the lower end of an upper link 162. The upper end of this link 162 is rigidly afiixed to the control rod 164, having a handle 166. Rotation of the handle 16d and control rod 164 Will effect rotation of the upper link 162 so as to cause it to lift the intermediate link 158. Upward movement of the link 158 will in turn effect upward movement of the lower link 156 and hence It should be particularly noted that the lower link 156 is formed with a slot 168 whereby there may take place lost mot-ion between the link 156 and the link 158 at such time as the stopper 136 is raised under the influence of float 3% or the vis- .cosity-sensing means 44 Referring now to Figures 3 and 4, there is shown a preferred form of hand control bank for usewith a tank bleeding device embodying the present invention. This control bank includes the

aforementioned handles

130, 138 and 16d, and is-adapted to'provide a convenient way of connecting the three handles with the three control rods 12%, 136, and 16d. To this .end, the control bank includes a housing 17s wherein are housed shafts 172 and 1'74. The left stub shaft 172 includes a rigidly mounted gear 176 which meshes with a mating gear 178 rigidly aflixed to the shaft 136. The right stub shaft 174 in turn rigidly mounts a gear 18% which meshes with a mating gear 182 rigidly mounted by the shaft 164. With this arrangement, rotation of the handles 13% and 166 will effect the desired rotation of the

shafts

136 and 164, re-

- spectively. The handle 13b is seen to --be directly fixed to the outer end of the control rod 126.

It is believed that the control andoperation of the preferred form of tank bleeding device will be apparent from .the foregoing detaileddescription. Generally, however, it will be observed that the buoyant effectiveness of the float 38 may be controlled by rotation of the handle 13f whereby the float may be adjusted to remain in a raised position while immersed in a liquid of one specific gravity and to sink when immersed in a liquid having a lower specific gravity. Ordinarily, the liquid of the greater specific gravity will be water, whereas the liquid .138 will control the elfective combined area of the two

discs

104 and 106. Normally these discs will be adjusted whereby a liquid such as water having a comparatively low viscosity will not effect upward movement of the stopper, but at such time as these discs are exposed to the flow of liquid having a comparatively high viscosity, such as a heavy oil, the stopper will be moved upwardly so as to close the orifice 30. The handle 130 may be turned so as to effect the opening or closing of the orifice at any time independently of the action of the float 38 or the viscosity-sensing means 40.

Although there has been described what is at present considered to be the preferred form of tank bleeding device embodying the present invention, it will be apparent to those skilled in the art that various modifications and changes may be made thereto. For example, it is possible to modify the aforedescribed device for use within a pipeline adapted to carry liquid of various specific gravities and viscosities in such a manner that flow through the pipeline could be automatically cut oil upon the presence of a liquid having a predetermined specific gravity or viscosity. Other modifications and changes may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of different specific gravities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; linkage interconnecting said rod and said sleeve whereby upward movement of said rod will effect movement of said stopper away from said orifice; and control means operable externally of said tank for effecting vertical movement of said stopper independently of said float means.

2. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of different specific gravities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; a rack element formed at the upper end of said rod; a support block slidably mounted by said base for vertical movement relative thereto; a horizontal shaft rotatably mounted by said block; a pinion rigidly affixed to said shaft and meshed with said rack; a weight secured to said shaft so as to cause said pinion to bias said rack upwardly; control means operable from externally of said tank for varying the effectiveness of said weight; linkage interconnecting said rod and said sleeve whereby upward movement of said rod will effect movement of said stopper away from said orifice; and control means operably externally of said tank for effecting vertical movement of said stopper independently of said float means.

3. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of different specific gravities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base,

said rod being coaxially disposed within said sleeve; a rack element formed at the upper end of said rod; a support block slidably mounted by said base for vertical movement relative thereto; a horizontal shaft rotatably mounted by said block; a pinion rigidly aflixed to said shaft and meshed with said rack; a weight secured to said shaft so as to cause said pinion to bias said rack upwardly; control means operably from externally of said tank for adjusting the vertical position of said block whereby the elfectiveness of said weight may be varied; linkage interconnecting said rod and said sleeve whereby upward movement of said rod will effect downward movement of said stopper relative to said orifice; and control means operable from externally of said tank and connected with said sleeve for eflfecting vertical movement of said stopper independently of said float means and said weight.

4. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of different specific gravities and viscosities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed Within said sleeve; an apertured disk carried by the lower portion of said stopper; a second apertured disk vertically spaced below said first apertured disk; a second sleeve supporting said second apertured disk, said second sleeve being telescopically mounted between said rod and said first sleeve, said disks being relatively rotatable so as to vary their effective combined area exposed to liquid entering said orifice; and, linkage interconnecting said rod and said first sleeve whereby upward movement of said rod will effect downward movement of said stopper away from said orifice.

5. A tank bleeding device disposable within the con fines of a liquid storage tank containing liquids of different specific gravities and viscosities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; an apertured disk carried by the lower portion of said stopper; a second apertured disk vertically spaced below said first apertured disk; 3. second sleeve supporting said second apertured disk, said second sleeve being telescopically mounted between said rod and said first sleeve, said disks being relatively rotatable so as to vary their eliective combined area exposed to liquid entering said orifice; linkage interconnecting said rod and said first sleeve whereby upward movement of said rod will effect downward movement of said stopper away from said orifice; and control means operable externally of said tank for elfecting Vertical movement of said stopper independently of said float means and said disks.

6. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of different specific gravities and viscosities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; a rack element formed at the upper end of said rod; a support block slidably mounted by said base for vertical movement relative thereto; a horizontal shaft rotatably mounted by said block; a pinion rigidly aflixed to said shaft and meshed with said rack; a weight secured to said -shaft so as to cause said pinion to bias said rack upwardly; an apertured disk carried by the lower portion of said stopper; a second apertured disk vertically spaced below said first apertured disk; a second sleeve supporting said second apertured disk, said second sleeve being telescopically mounted between said rod and said first sleeve, said disks being relatively rotatable so as to vary their effective combined area exposed to liquid entering said orifice; and, linkage interconnecting said rod and said first sleeve whereby upward movement of said rod will effect downward movement of said stopper away from said orifice.

7. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of different specific gravities and viscosities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plat-e mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a

vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; a rack element formed at the upper end of said rod; a support block slidably mounted by said base for vertical movement relative therto; a horizontal shaft rotatably mounted by said block; a pinion rigidly afiixed to said shaft and meshed with said rack; a weight secured to said shaft so as to cause said pinion to bias said rack upwardly; control means operably from externally of said tank for varying the effectiveness of said weight;

linkage interconnecting said rod and said first sleeve whereby upward movement of said rod will effect downward movement of said stopper relative to said orifice; an apertured disk carried by the lower portion of said stopper; a second apertured disk vertically spaced below said first apertured disk; a second sleeve supporting said secondapertured disk, said second sleeve :being telescopically mounted between said rod and said first sleeve, said disks being relatively rotatable so as to vary their effective fltroil means :operably from externally of :said tazrkfor effecting relative rotation of said disks; and, control means op- "erable from externally of said tank for effecting vertical movement of said stopper independently of said float means and said disks.

8. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of different specific gravities and viscosities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; a rack element formed at the upper end of said rod; a support block slidably mounted by said base for vertical movement relative thereto; a horizontal shaft rotatably mounted by said block; a pinion rigidly affixed to said shaft and meshed with said rack; a weight secured to said shaft so as to cause said pinion to bias said rack upwardly; control means operable from externally of said tank for adjusting the vertical position of said block whereby the effectiveness of said weight may be varied; linkage interconnecting said rod and said sleeve whereby upward movement of said rod will effect downward movement of said stopper relative to said orifice; an apertured disk carried by the lower portion of said stopper; a second apertured disk vertically spaced below said first apertured disk; a second sleeve supporting said second apertured disk,

said second sleeve being telescopically mounted between said rod and said first sleeve, said disks being relatively rotatable so as to vary their effective combined area exposed to liquid entering said orifice; control means operably from externally of said tank for effecting relative rotation of said disks; and, control means operable from externally of said tank for effecting vertical movement of said stopper independently of said float means and said disks.

9. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of difierent specific gravities and viscosities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; linkage interconnecting said rod and said first sleeve whereby upward movement of said rod will effect downward movement of said stopper relative to said orifice;

a horizontal disk formed with a plurality of segmental apertures extending inwardly from its periphery, said disk being rigidly mounted upon the lower end of said stopper; a second horizontal disk similar in size and configuration to said first disk spaced vertically therebelow; a second sleeve rigidly mounting said second disk upon its lower end, said second sleeve being telescopically mounted between said rod and said first sleeve, said disks cooperating as viscosity-sensing means adapted to urge said stopper upwardly into said orifice when their effective comexterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by asleeve coarrial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; a rack element formed at the upper end of said rod; a support block slidably mounted by said base for vertical movement relative thereto; a horizontal shaft rotatably mounted by said block; a pinion rigidly aflixed to said shaft and meshed with said rack; a weight secured to said shaft so as to cause said pinion to bias said rack upwardly; control means operable from externally of said tank for varying the effectiveness of said weight; linkage interconnecting said rod and said first sleeve whereby upward movement of said rod will effect downward movement of said stopper relative to said orifice; a horizontal disc formed with a plurality of segmental apertures extending inwardly from its periphery, said disc being rigidly mounted upon the lower end of said stopper; a second horizontal disc similar in size and configuration to said first disc spaced vertically therebelow; a second sleeve rigidly mounting said second disc upon its lower end, said second sleeve being telescopically mounted between said rod and said first sleeve, said discs cooperating as viscosity-sensing means adapted to urge said stopper upwardly into said orifice when their efiective combined area is exposed to liquid having a predetermined viscosity moving at a predetermined velocity; pin means keying said second sleeve to said rod whereby they may undergo relative longitudinal movement while being locked against relative rotational movement; control means operable from externally of said tank for effecting rotation of said rod so as to adjust the efiective combined area of said discs; and control means operable from externally of said tank for efiecting vertical movement of said stopper independently of said float means and said viscosity-sensing means.

11. A tank bleeding device disposable within the confines of a liquid storage tank containing liquids of diflerent specific gravities and viscosities, comprising: a base; float means supported by said base for vertical movement relative thereto; an upwardly opening orifice plate mounted by said base, its orifice being connectible with a point exterior of said tank; a stopper movable vertically toward and away from said orifice, said stopper being supported by a sleeve coaxial with said orifice; a vertical rod rigidly connected to said float means and supported by said base, said rod being coaxially disposed within said sleeve; a rack element having circumferential teeth formed at the upper end of said rod; a support block slidably mounted by said base for vertical movement relative thereto; a horizontal shaft rotatably mounted by said block; a pinion rigidly afiixed to said shaft and meshed with said rack; a weight secured to said shaft so as to cause said pinion to bias said rack upwardly; control means operable from externally of said tank for adjusting the vertical position of said block whereby the effectiveness of said weight may be varied; linkage interconnecting said rod and said sleeve whereby upward movement of said rod will effect downward movement of said stopper relative to said orifice; a horizontal disc formed with a plurality of segmental apertures extending inwardly from its periphery, said discs being rigidly mounted upon the lower end of said stopper; a second horizontal disc similar in size and configuration to said first disc spaced vertically therebelow; a second sleeve rigidly mounting said second disc upon its lower end, said second sleeve being telescopically mounted between said rod and said first sleeve, said discs cooperating as viscosity-sensing means adapted to urge said stopper upwardly into said orifice when their effective combined area is exposed to liquid having a predetermined viscosity and moving at a predetermined velocity; a guide member rotatably carried by the upper end of said base in coaxial alignment with said rod, said guide member being formed with a vertical bore for slidably receiving said rack; pin means keying said guide member to said rack whereby they may undergo relative longitudinal movement while being locked against rotational movement; pin means keying said second sleeve to said rod whereby they may undergo relative longitudinal movement while being locked against rotational movement; control means operable from externally of said tank for effecting rotation of said guide member so as to adjust the effective combined area of said disks; and control means connected to the upper end of said first sleeve and operable from externally of said tank for eifecting vertical movement of said first sleeve and said stopper independently of said float means and said viscosity-sensing means. 7

12. A device sensitive to liquid viscosity and velocity for use in moving a stopper into an orifice closing position in a tank bleeder, including: a stopper having a central bore formed therein; a first tubular member extending upwardly through said bore; a first apertured plate sensitive to liquid velocity and viscosity mounted on the lower end portion of said tubular member; a second apertured plate mounted on the lower end of said stopper and vertically spaced from said first plate; a rod projecting upwardly through said bore, which rod has a longitudinally extending slot formed therein and is disposed Within the confines of said bore; a pin transversely disposed in said tubular member that extends across said bore and slidably engages said slot; and means for rotating said rod and moving said first plate relative to said second plate to obtain a plate arrangement that offers sutficient fluid friction to cause upward movement of said stopper into sealing engagement with said orifice when a liquid having a particular velocity flows by said plates at greater than a predetermined maximum rate of flow.

13. A device as defined in claim 12 in which said first and second plates are circular and have apertures formed therein in the shape of notches cut from the circumferential portions thereof.

14. A device as defined in claim 12 in which manually operable means are provided for moving said stopper into an orifice obstructing position in the event of an emergency.

References Cited in the file of this patent UNITED STATES PATENTS 1,566,147 Lenz Dec. 15, 1925 2,016,867 Marden Oct. 8, 1935 2,098,131 Bluhm Nov. 2, 1937 2,601,777 Woodward July 1, 1952,