US2404087A - Gauging and sampling device - Google Patents

Description

Jy 16, 1946. H. o. PARSONS GAUGING AND SAMPLING DEVICE Filed March 15, 1945 INVENTOR. 6

Patented July 16, 1946 GAUGING AND SAMPLING nEvioE Harrison 0. Parsons, Houston, Tex.

Application March 13, 1945, Serial No. 582,558 U 4Clairns. (01.734293) Q This invention relates to a device for gauging and sampling liquids stored in aclosed container under superatmospheric conditions. The device of'the present invention is particularly adaptable to portable containers such as railroad tank cars which are used for transporting liquefied hydrocarbons under relatively high pressures and is provided with a plurality of valve means arranged to prevent loss of liquid from the container even though parts of the device are injured or destroyed by accident.

The invention andits scope may befully understood from the following description read in conjunction with the accompanying drawing in which Figs. 1 and 2 together constitute a side elevation, with parts broken away, of, an embodiment of' the present invention;

Fig. lshowing the upper portionv and Fig. 2 thelower portion of the device;

Fig.3 isa fragmentary view of a portion of the mechanism of Fig. l with the view taken at 90 toFig.1; and V Fig. 4 is a view .taken along line IV-IVv of Fig.1. r v v Referring now specifically to the drawing, a coupling member II' is arranged to be secured to the top wall of a container. The Walls of the container are not shown since the construction of storage tanks suitable for storing liquids under superatmospheric pressure is conventional to the art and it will be understood that coupling member ll is secured to the wall of a container in a suitable fluid-tight manner; Coupling member ll defines a vertically extending passage 12. Fitting upon coupling member I l' is a base member 14 which is secured to the coupling member in a fluid-tight manner. In the drawing mating screw threads [5 are shown as the means for securing the base member to the coupling member. It will be understood, however, that other suitable means for attaching the two members in a fluid-tight manner, such as by the use of cap screws, may be employed. Base member l4 defines a vertically extending central passage in which gauging tube [6 is slidably arranged. Gauging tube H5 is provided with suitable calibrations ID; A tapering seat .I'! is defined by base. member [4 adjacent the lower end of the central passage; Base member I4 is additionally provided with packing l8 and packing gland l9 which is arranged to prevent loss of fluid vbetween gauging tube l5 and the base member. Secured to the upper end of gauging tube Iii-is a head member A which carries ,valves which will h reafter be describedgreater detailand secured to the lower end or gauging tube 16 is tubular member B which also carries a valve which will be described in greater detail hereafter. .7 i V ,1

A safety hook and sighting level screw member 20 is attached to the upper surface of base mem: ber 14.. Cap 2|, of suitable dimensions to cover head member A and the valve members incorporated therein, is secured to thebasemember by screw threads 22 arranged to engage corre: sponding threads formed on the base member. A passage 23 is formed in base member l4 and arranged to vent the space enclosed by .cap 2] to the atmosphere as the cap is being disengaged from the head member. 7

Head member A is secured to the upperend of gauging tube [6 by mating screw threads; Head member A may be said to be of a generally tubular shape and defines a central passage 13 provided with a circular inwardly extendingledge 25 arranged some distance above ,the upper end of gauge rod l6. Ledge 25 forms a restfor valve member 26: which is mounted in the cen-j tral passage belowledge 25 and is providedwith a conically formed upper surfaceadapted to oooperate with ledge 25. vValve member 26 is biased upwardly against ledge 25 by spring 21. It will be noted that the upper end ofspring 2ljdoes not itself come into contact with valve-member 26, but instead bears on a spring retainer;mem-' ber 28 which is shaped to allow the flow of fiuid through passage [3. Spring retainer members 28 forces the valve. member. 26 againstthe circular ledge 25. e .u

Mounted on the upper end of head member A is a bonnet 29 provided with a valve stem 30 which in turn is surmounted by hand wheel 3]; The space between bonnet 29 and stem 3|] is controlled by packing 32 held in place by stuffing box nut 33. The valve stem 30 may be moved downwardly by rotation of hand wheel 3| and upon engagement of the lower end of valve stem 30 with valve member 26 the valve member is pushed away from circular ledge 25 so that fluid may flow through central passage l3. Valve stem 30. is provided with left-handed threads'. The reason for this isthat conventional valves-are opened by turning counterclockwiseand closed by turning clockwise. If stem 30 were provided with right-handed threads, its operation would be the reverse of that of conventional valves. Consequently, it is convenient td employ lefthanded threads in this case.

Above circular shoulder 25 central passage I3 is connected with a port 34 which extends at right angles to passage l3. Port 34 discharges into a passage 35 which is of substantially larger diameter than port 34. Within passage 35 is seated a valve 36 which is in the form of a screw thread plug having a conical projection 31 at its forward end which is adapted to seat at the outer end of port The flui p ssage through the valve 36 begins at the base of the conical projection and passes through the center of the plug. The outer end of the plug is provided with a circumferential shoulder 38 adapted to abut against a ledge 39, in this case the head of a screw, to limit outward motion of the plug. The plug 36 is of such dimensions that when it is in closed position its outer end is flush with the inside surface of cap 2|, that is to say, that cap 2| cannot be screwed into place unless the valve 36 is in closed position.

Secured to head member A is laterally extending rod 40 arranged to cooperate with safety hook and sighting level member 28. It will be seen that the upper end of member 20 defines a hook designated by numeral 4 When the gauge rod is lowered into the container with member A adjacent stulfing box l9, rod 40 is below the lower surface of hook 4|. It will be apparent that the head member A may be rotated with respect to base member 4. When head member A is in the position shown in Fig. 4, rod 49 is engaged with the hook portion 4| of the safety hook and sighting level member 26 and when thus engaged head A is locked against upward movement. If the head A is moved in a counterclockwise direction from the position shown in Fig. 4 the rod 40 becomes disengaged from hook member 4| and thereafter head A is free to move in-a vertical direction. It will be observed that the central passage through which gauge member 16 is adapted to slide is slightly eccentric with respect to the screw threads 22 arranged for securing cap 2| to base member I4. This arrangement requires that rod 46 be immediately below hook 4| before cap 2| can be screwed into position and prevents gauge member 6 from being forced upwardly by pressure in the container as long as cap 2| is in position on base member M. A bail 42 is pivotally mounted on head A; A recess 43 is provided in the bail and adapted to receive valve stem 30 when valve 26 .is in a closed position. One end of ball 42 is provided with a lug 44 adapted to abut against .stop 45 arranged in head A to limit the movement of the bail. Bail 42 'is of such shape and dimension that it is capable of only slight movement from its vertical position when cap 2| is in place inasmuch as one side of the bail sets fairly snugly against the side wall of cap 2| when the bail is in vertical position. The dimensions of the bail are such that it cannot be placed in a vertical position unless valve 26 is in closed position. Consequently, the bail prevents the setting of cap 2| in place unless valve 26 .is in closed position.

' Member B is secured to the lower end of gauge tube It; by suitable screw threads 46. Side ports 4'! provide communication between the exterior of member B and a central passage 43 thereof. The upper end of passage 48 communicates with a corresponding central passage 49 in gauge member l6 while the lower end of passage 48 is closed by a suitable plug 50. Member B defines a valve seat in passage 48 at a point above the side ports and arranged below the seatis ball 52 which is adapted to cooperate therewith and close the central passage when the ball is in its uppermost position. A spring 53 is arranged in the central passage between plug 50 and ball 52 and biases the ball upwardly against seat 5|.

A rod 54 is slidingly arranged in passage 49 of gauge member 6 with the dimensions of the rod and passage such that an annulus is provided through which fluid can flow. The upper end of rod member 54 is attached to spring retainer 28 by suitable means such as screw threads 54'.

.Rod 54 is of such length that when valve member 26 engages with the seat defined by ledge .25 the lower end of the rod is above ball 52 but when valve member 26 is forced downwardly away from ledge 25, the lower end of rod 54 comes .in contact with ball 52 and. forces it downwardly away from seat 5|. In other words, the rotation of hand wheel 3| to move stem 30 downwardly first forces member 26 away from its seat and opens the upper valve and additional rotation forces ball 52 away from its seat and opens the lower valve.

The lower portion of member B at a point below side ports 4'! is enlarged to form a shoulder which is provided with a surface 55 tapering outwardly and downwardly and of such a shape that when brought into contact with seat I! it engages therewith to form a fluid-tight seal. Spaced slightly below seat 55 is an outwardly extending circular ledge 55. A spring 57 is secured to the lower surface of base member M with its upper end secured to the base member and its lower end secured to an annulus 58 of substantially the same diameter as ledge 56. The arrangement of spring 5'1, annulus 58 and ledge 56 is for absorbing the shock in the event a high pressure within the container drives gauging tube |6 upwardly.

The arrangement of seat 55 of member B and seat I! of base member I4 allows packing 18 to be renewed without releasing the pressure from the container. If it is found desirable to add additional packing I8 or to renew packing |8 while under pressure, the gauging tube l6 may be drawn upwardly until tapering surface 55 engages seat l! and forms a fluid-tight seal at the lower end of the central passage of base member l4. After surfaces 55 and I1 have been brought into engagement, stufiing box gland l9 may be removed, packing l8 replaced and the stuffing box nut .|9 returned into position without releasing pressure from the container.

The device of the present invention may be employed to determine the liquid level in the container in the following manner. Cap 2| is removed from base member l4 and head member A rotateduntil rod 40 clears hook member 4|. The valve means with which the device is providedmay then be opened by rotating hand wheel 3-! to move valve stem downwardly and force valve members 26 and .52 from their respective seats. Valve member 36 may then be opened. The superatmospheric pressure in the container will then cause fluid to pass upwardly through the passage defined by ports 41, passages 48 and 49, port 34 and passage 35. The gauge member I6 is moved vertically to determine the lever at which liquid discharges and above which vapors are discharged; at this point it is known that ports 4'! have been lowered to the liquid level and a reading may be taken on scale II].

It will be understood that the upper surface of the hook portion 4| of safety hook and sighting level member 20 may be used to define theline of sight when reading the graduations of scale l0 when determining the liquid level in the container.

The device of the present invention is particularly advantageous for the handling of low molecular weight hydrocarbons such as butane or mixtures" including substantial amounts of butane or light hydrocarbons. If water is present in the material being gauged, the refrigeration caused by the release of the vapors to the atmosphere may cause the upper portion of the gauging device to become frozen. In the arrangement of the present invention, the valve placed in member B remains submerged in the liquid of the container and at a sufliciently high temperature to prevent freezing thereof. The arrangement of the present invention has the dual advantages that if an accident occurs to the valve head A to render the valve in the upper end of the device useless, the lower valve in member B remains operable and in addition the freezing effects sometimes encountered with respect to the valve at the upper end of the device when releasing high pressure vapors to the atmosphere do not prevent the lower valve from being operable.

Having fully described the device of the present invention, what I desire to claim is:

1. A gauge suitable for determining the level of liquid in a container under superatmospheric pressure comprising, in combination, a base member defining an opening, an elongated body having a longitudinal passage extending therethrough slidably arranged in the opening in said base member, packing means arranged to seal the space between the base member and the elongated body, a valve seat defined in the lower end of said elongated body through which said passage extends, a valve seat defined in the upper end of the body through which the passage extends, a first valve member arranged in the passage adjacentthe lower valve seat, means biasing said first valve member against said valve seat, a second valve member arranged in the bod; adjacent the upper valve seat, means biasing the second valve member against the upper valve seat, a valve stem mounted on the upper end of said elongated body and arranged for movement with respect thereto for forcing said second valve member away from the upper valve seat and a rod member mounted in the elongated passage between the first and second valve members and arranged to force the first valve member away from the lower valve seat upon movement of the second valve member away from the upper valve seat.

2. A gauge suitable for determining the level of liquid in a container under superatmospheric pressure comprising, in combination, a base member adapted to be secured to the container and defining a vertically extending passage with a seat on the lower surface of the base member adjacent the lower end of the passage, an elongated body having a longitudinal passage extending therethrough, said body being slidably arranged in the passage defined by the base member, a packing means arranged to seal the space between the base member and the elongated body, an outwardly extending shoulder carried by the lower end of said elongated body and defining an upper surface adapted to cooperate with the seat defined by the base member to seal the passage defined by the base member when said shoulder is brought into contact with the base member, a, lower valve seat and an upper valve seat through which the longitudinal passage extends defined in the lower and upper ends of the elongated body respectively, a first valve member carried by the elongated body adjacent the lower valve seat, means biasing said first valve member against said valve seat, a second valve member arranged in the elongated body adjacent the upper valve seat, means biasing the second valve member against the upper valve seat, a valve stem mounted in the upper end of said elongated body and arranged for movement with respect thereto for forcing said second valve member away from the upper valve seat and a rod member mounted in the elongated passage between the first and second valve members and arranged to force the first valve member away from the lower valve seat upon movement of the second valve member away from the upper valve seat.

3. A device in accordance with claim 2 in which a gland is secured to the base member adjacent the upper end of the passage defined by the base member to hold said packing means in position.

4. A device in accordance with claim 2 in which a packing gland member is secured to the upper portion of the base member adjacent the central passage defined by the base member to secure the packing means in position and in which the passage defined by the elongated body above the upper valve seat discharges to the atmosphere and defines a third valve seat and a third valve member mounted on the elongated member to seal said third valve seat.

HARRISON O. PARSONS.

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