US3541858A

US3541858A - U-tube manometer with shipping seal

Info

Publication number: US3541858A
Application number: US747896A
Authority: US
Inventors: Joseph E Bonczek
Original assignee: Scott and Fetzer Co
Current assignee: Adalet Scott Fetzer Co
Priority date: 1968-07-25
Filing date: 1968-07-25
Publication date: 1970-11-24
Anticipated expiration: 1987-11-24

Description

Nov. 24, 1970 J. E. BoNczEK U-TUBE MANOMETER WITH SHIPPING SEAL Filed July 25, 1968 United States Patent O 3,541,858 U-TUBE MANOMETER WITH SHIPPING SEAL Joseph E. Bonczek, Elyria, Ohio, assignor, by ruesne assignments, to The Scott & Fetzer Company, Lakewood, Ohio, a corporation of Ohio Filed July 25, 1968, Ser. No. 747,896 Int. Cl. G01l 7/18 U.S. Cl. 73-401 7 Claims ABSTRACT OF THE DISCLOSURE `Combination including a removable internal seal for a bore, especially adapted for sealing liquid inside tubing, such as sealing mercury inside a closed-end, absolute pressure gauge, U-tube, wherein the seal is adapted to be inserted into a long bore, to be moved into sealing position or into a removable position by manipulation from outside of the bore, and to follow the expansion or contraction of the liquid in the bore without permitting air leakage between the seal and the liquid surface.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a removable, internal seal for a bore and any suitable combination containing that seal. More specifically, the invention relates to sealing a bore in tubing with said seal, and still more specifically relates to sealing mercury in a mercury lled, closed-end, absolute pressure U-tube for a manometer, as disclosed herein.

The closed-end, glass, absolute pressure U-tube of a manometer has the leg of its closed end iilled full, and of its open end filled only to a short distance around the U-bend, as shown in FIG. 3, when its is first filled. After filling and during shipping, the problem is to hold the mercury in the U-tube, in the same manner as it is iilled by the manufacturer; so that in shipment to the user of the U-tube, the mercury is not lost nor is air permitted to get into the mercury where it might migrate through the mercury, around the U-bend and into the closed end of the U-tubev to break the vacuum therein, or to reduce the complete filling of the closed end with mercury.

The seal of the present invention solves all of these problems by being easily insertable into the open end after the U-tube has been filled with mercury, sealing the surface of the mercury against air entry thereto, readily following the surface of the mercury during its expansionv or contraction to prevent breakage of the glass tube by expansion of the mercury and to prevent entry of air thereto during contraction, and readily removable from the open end of the U-tube when the U-tube reaches its destination and is ready for use.

This seal may be used either in a shipping block for shipping replacement U-tubes lled with mercury or in the original manometer cap block used not only to cap the orignnal U-tube during shipment of the original manometer but also as a cap block in the manometer during manometer operation.

An object of the present invention is to provide a seal for a bore easily movable by manipulation from outside the bore into a sealing position for sealing the bore or into a removable position for removal from the bore and/or for following the surface of any liquid within the bore during any expansion or contraction of the liquid therein.

A further object of the present invention is to provide a seal for retaining mercury within a U-tube of a manometer whether the U-tube has one open and one closed end or both open ends.

3,541,858 Patented Nov. 24, 1970 ICC A further object of the present invention is to provide a block clampable over the distal ends of a manometer U-tube for resiliently and detachably retaining a seal for mercury therein and/ or supporting and spacing apart the distal ends of the U-tube while any deflecting force is applied thereto, such as during shipping or use.

A further object of the present invention is to provide a seal for a bore having two axially spaced apart and radially expandable and contractible O-rings for providing a leak-proof seal easily slidable by an axial force within the bore and easily removable from the bore, when desired.

A further object of the present invention is to provide a seal with or without a retaining block and adapted to be used with a U-tube of a manometer characterized by its inexpensive manufacturing cost, ease of assembly of its component parts, structural simplicity, many desirable operational advantages, ease of operation oruse, and multiplicty of functional advantages for some component parts thereof.

These and other objects, novel features and additional advantages of the present invention will become more clearly apparent by reference to the appended claims as the following detailed description and discussion proceeds in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing,

FIG. 1 is an elevational view, partially in section, of a flow conduit and a manometer using a mercury filled, closed-end, absolute pressure U-tube for measuring the upstream pressure in the flow conduit for giving the characteristics of flow through the ilow orifice thereof to atmosphere by measuring absolute pressure;

FIG. 2 is a perspective view of a shipping unit for ship- Vping a replacement U-tube for the manometer in FIG l;

FIG. 3 is a longitudinal sectional view of the shipping unit in FIG. 2; and

FIG. 4 is an enlarged, side elevational view, partially in section, of the seal in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the present invention in a seal has many uses, it will be specifically disclosed herein in connection with U-tube 20 of absolute pressure manometer or gauge 18 in FIG. 1.

Manometer or gauge 1'8 may be of any suitable type with its usual usage being disclosed in FIG. 1. There, fluid is flowing in flow direction D through flow conduit 10 and through orilice 12 to atmosphere, and manometer or gauge 18 is used to aid in obtaining the characteristics (volume, velocity, etc.) of the owing fluid by giving the pressure drop measured across orice 12 by the upstream pressure being transmitted through upstream pressure tap 14 in conduit 10, and flexible pressure line 16 to open end 20a of U-tube 20 in manometer or gauge 18. Since the other end of U-tube 20 is closed end 20b, absolute pressure P in FIG. l is measured by manometer or gauge 18 to be used in calculating any of these characteristics.

Manometer or gauge 18 includes a plurality of interconnected parts, including U-tube 20, mercury 22, base 24, clamps 26, scale 28, screws 30, manometer cap block 32, and gaskeets 25.

U-tube 20 has at least one open end 20a with a generally uniform diameter bore 20c, similar to a bore of tubing, therein containing mercury. Although it should be readily apparent hereinafter that some aspects of this invention may be used with a manometer U-tube having both ends open connected by a uniform diameter bore, it has been chosen to show herein U-tube 20 having one 3 closed end 20h to form an absolute pressure gauge. This closed end is now completely lled with mercury, at the time of lling, so as to evacuate all air therebetween to keep the space between the surface of the mercury (in the space between the open end U-leg and closed end 2Gb) free of air and to keep closed end 20b substantially a vacuum. Flow restriction 20d is located in bore 20c to serve as a surge damper. For example, if a high vacuum is being sensed by pressure line 16 and this vacuum is suddenly vented to atmosphere, this surge damper or throttling means 20d restricts the speed of mercury travel toward closed end 20b to prevent the possibility of the mercury knocking off closed end 2Gb by its rapid Velocity.

Although any suitable liquid may be contained in tube 20, it is generally lled with mercury.

Gauge base 24 is here shown as a one-piece casting comprising sheet-like base plate 24b, coplanar with the plane of the drawing; U-shaped wall 24d and cap 24f extending around the periphery of base plate 2417 and out of the plane of plate 24b in the direction out of the plane of the drawing; and recess 24h, formed by wall 24d and cap 24]c and greater in depth than the thickness of U-tube 20, seen in front of base plate 24h in FIG. 1. U-tube 20 is mounted in recess 24h by telescoping its two distal ends 20a and 2Gb through two annular gaskets 25 telescoped into parallel holes 24m in cap 24h; swinging the base of the U toward plate 24h and into recess 24h; and detachably securing U-tube 20 in recess 24h by one or more detachable clamps 26.

Manometer scale 28, having graduations 28a thereon for measuring absolute pressure by measuring the differential heights of the mercury columns in the two legs of the U-tube 20, is secured by one or more screws 30 with each screw 30 extending through slot 28b in scale 28 and screwed into a threaded hole carried by base plate 24b.

Suitable clamping means 33 secures block 32 to base 24. Manometer cap block 32 is secured to base 24 by stud 34, rigidly secured at its lower end to base 24, such as in a threaded hole in cap 24f, extending up through a central hole in block 32, and having a wing nut 36 screwed onto threaded upper end of stud 34. When nut 36 is tightened, it pulls block 32 downwardly in FIG. 1 to Squeeze gaskets 25 to mount resiliently and firmly the upper and

distal ends

20a and 20b of U-tube 20 in base 24 to form complete manometer or gauge 18.

Block 32 may be made of any suitable material but is generally made of metal, has two axially extending parallel holes 32a and 32b for receiving respectively U-tube ends 20a and Z012, and has pressure port 32]c extending laterally from hole 32a and adapted to be detachably connected at its outer end with pressure line 16.

U-tube 20, when removed from gauge 18, is filled with mercury 22 along the full length of its leg having closed end 2Gb, around the base of the U, and along a short distance up the other leg toward open end 20a. The problem is to hold the mercury in the open end leg of the U-tube so that in shipment the mercury is not lost (runs out of) U-tube 20, nor is air permitted to get into the mercury where it might migrate around the U-bend to get into the mercury in the leg having the closed end so as to break the Vacuum or to reduce the complete lling of the closed end leg.

Removable, internal, piston-type seal 40 in FIGS. '2, 3 and 4 is used to seal or hold the mercury in U-tube bore 20 in the desired manner. Seal 40 includes rod 42, sealing means 44 and suitable seal control means 48.

Rod 42 is shown herein as a smooth, metal rod, having enlarged head 42a and threads 42h at opposite ends connected by smooth cylindrical portion 42e of uniform diameter; and adapted to telescope into bore 20c, as shown in FIG. 3, where this seal is in its sealing position.

Sealing means 44 includes one or more seal members 45 and one or

more collars

46 and 47, each shown herein as annular in shape, telescopcd onto, surrounding, op-

eratively connected to cylindrical portion 42e of rod 42 and being telescopable with rod 42 into bore 20c into sealing position shown in FIG. 3. Here, seal members 45 comprise two, axially aligned, annular, resilient, O- ring seal members 45 made of suitable rubber-like material snugly surrounding and telescoped over rod cylindrical portion 32C. These two seal members 45 are preferably of equal size, as shown in the drawing, for forming two, parallel, axially spaced apart, circular seals having the same durometer hardness and forming seals with uniform diameter, cylindrical bore 20c. However, it should be readily apparent that these seal members 45 may have different durometer hardnesses, such as a softer durometer in the lowermost sealing member in FIGS. 3 and 4 to provide a better sealing action and a harder durometer inthe lowermost sealing member in FIGS. viding a better centering alignment in bore 20c. Also, one of the seal members 45 may have a larger peripheral diameter relative to the axis of rod 42 or may have a larger circular cross sectional diamter of its annulus (shown by the rubber cross hatching in FIG. 4) than the other seal member 45 to give certain preferred characteristics to seal 40.

Seal control means 48 is provided with rod 42 for moving sealing means 44 into sealing position for sealing bore 20c or into a removable position for removal from bore 20c. Although this seal control means 48 may take the form of a manually graspable portion on the upper end of rod 42 in FIGS. 3 and 4 so that sealing means 44 could be pushed as a xed piston downwardly into the sealing position shown in FIG. 3 or pulled axially in the upward direction until sealing means 44 clear the upper end of open end 20a in the removable position, seal control means 48 is shown herein as having a seal adjusting means 49 operatively connecting rod 42 and sealing means 44 and having manually adjustable portion 5l adjustable from outside bore 20c in FIG. 3 for moving, by a relative rotational movement, sealing means 44 between these position while sealing means 44 is in bore 26C. Seal control means 48 includes sleeve means 52 (comprising washer `54, sleeve 55 and one or

more collars

46, 47 coacting with rod head 42a and seal members 45) telescoped over rod 42 and operatively connected to sealing .means 44; and manually adjustable portion 51, here shown as nut 5l screwed onto rod threads 42b. Then, rotation of nut 51 advancing in the axial downward direction in FIG. 3 causes relative axial movement of rod 42 and the annular portions of sleeve means 52 for axially squeezing seal members 45 so as to radially expand seal members 45 from their contracted or removable position into their expanded or sealing position for sealing against bore 20c.

It should be readily apparent that seal 40 may be used to seal by its sealing means 44 the bore in any tubing or in specic U-tube 20 without the use of block 32 in FIG. l or block 132 in FIGS. 2 and 3. Seal 40 can be telescoped downwardly in FIG. 3 into open end 20a and bore 20c to seal this bore with seal 40 in the sealing position shown in FIG. 3. Since sleeve means 52 and rod 42 provide an axially elongated dimension between sealing means 44 and manually adjustable nut 51, manual adjustment can be made at nut 51, located outside bore 20c and open end 20a and far removed from sealing means 44, for sealing bore 26e by sealing means 44 far within tube bore 20c. As nut 51 is rotated in its downwardly advancing direction to expand seal members 45 radially outwardly into their sealing position into sealing engagement with bore 20c, two equal sized O-ring seal members 45 form two parallel, coaxial and circular seals with bore 20c. This action also squeezes the bore if O-ring seal members 45 radially inwardly into resilient engagement with the periphery of cylindrical portion 42e of rod 42 in sealing engagement in the sealing position for preventing, by this sealing action with bore 20c and rod portion 42e, liquid mercury in bore 20c from traveling upwardly past sealing means 44 in FIG. 3. This same action also causes lower O-ring seal member 45 to be squeezed axially against the transverse planar face of lower collar 46 in FIG. 3 to form a circular seal therewith by resilient engagement; if this lower collar either were formed as an enlarged, integral head on the lower end of rod y42, or had a tight fitting hole telescoped over the periphery of rod portion 42e, this sealing engagement with the collar and of the periphery of O-rings 45 lwith bore 20c would prevent liquid mercury 22 in bore 20c from traveling upwardly past sealing means 44.

Seal -40 retains mercury 22 within tube 20, prevents air from entering to break the vacuum during shipment of tube 20 and permits easy withdrawal of seal 40 from bore 20c when tube 20 has reached its destination of ultimate use. First, seal 40 can be moved into sealing position by axially inserting sealing means 44 downwardly into the position shown in FIG. 3, and then rotating nut 51 in the downwardly axially advancing direction expands O-rings 45 into sealing position with bore 20c. Second, sealing means 44 follows the surface of mercury 22, as it expands and contracts, by moving axially in bore 20c in the appropriate direction as mercury filled U-tube 20 is handled, such as during shipping or transit. As variations in temperature occur, mercury 22 is caused to expand `or contract. Expanding mercury will push sealing means 44 in the upward axial direction in FIG. 3, while atmospheric pressure will push sealing means 44 in the downward direction to follow the surface of mercury 22 without the introduction of air bubbles axially downwardly past sealing means 44 into mercury 22.. Also, as the mercury contracts, vacuum is formed on the mercury surface side of sealing means 44 to aid this axial downward movement of sealing means 44. Hence, sealing means 44 freely axially follows the surface of mercury liquid 22 in the sealing position on axial expansion or contraction `of mercury 22 in tube 20. Third, when the shipping destination is reached and after the U-tube is ready for use to measure flow pressures, seal `40 is readily removable from bore 20c by rotation of nut 51 in the opposite direction to permit contraction of the outer peripheral sealing surface of O-rings 45 by their resiliency to permit axial upward removal of seal 40 from bore 20c.

The illustrated construction has been found superior to other tried constructions for many reasons. Some types sealing means 44 will stick in sealing position to bore 20c to prevent ready removal when use is desired, some have oil or other volatiles therein that will bleed out during rough handling in transit or during long storage to cause them to stick to bore 20c, some have to be squeezed so tightly in order to provide a good sealing action that they stick to the glass. In any event, any sticking, vulcanizing or practically cementing of sealing means 44 onto the surface of bore 20c will prevent sealing means 44 from following the surface of the mercury during expansion and contraction of the long mercury column 22, extending between closed end 20b and sealing means 44, upon variations in temperature; and will prevent subsequent re-moval of seal members 45 from bore 20c. Two, parallel, -O-ring, seal members 45 have the advantage over a single, O-ring, seal member in providing a double seal, minimizing the danger of cocking seal 40 in bore 20c, and minimizing the danger of leakage axially therepast since a nick or groove in the periphery of one O-ring, seal member 45 might permit some leakage therepast but the second O-ring -will prevent any substantial portion of this leakage from moving axially past it.

The axial length of seal 40 can be of any desired length governed by the axial distance between the manually adjustable portion 51 and sealing means 44 thereon. Seals 40 of six to thirty inch axial length have been used satisfactorily.

Although liquid mercury 22 is specically shown herein, it should be readily apparent that sealing means 44 and seal 40 can be used to hold any liquid or fluid in any suitable recess or container having a bore, such as tubing, even though closed end U-tube 20 is specifically shown herein.

The article or U-tube having a bore to be sealed can be made of any suitable material even though U-tube 20 is shown herein as being made of glass. For example, stainless steel U-tubes 20 for manometers or gauges 18 are frequently used and can be sealed with seal 40; these stainless steel tubes generally use a magnetic follower for detecting the surface of the mercury for measuring the absolute pressure P in FIG. 1 since this surface is not visible through the side of the tube.

Also, even though U-tube 20 is shown as having one closed end 20b, it should be readily understood that two seals 40 can be used, one in each open end, to seal both open ends of an open ended IU-tube commonly found in manometers so as to seal the mercury therein during shipment.

Seal `40 is also usable with retaining

block

32 or 132, if so desired, to form a shipping unit. Seal 40 can be used with either metal manometer cap block 32 in manometer or gauge 18 as originally shipped by the manufacturer to the user in the assembled condition shown in FIG. l but with seal 40 sealing mercury 22 therein, or Vwith wood shipping block 132 in FIGS. 2 and 3 when shipping a replacement U-tube 20 filled with mercury 22 at a later date to a user of manometer 18.

Blocks

32 and 132 respectively have two parallel holes 32a, 321) and 132a, 132b therein telescoped over the distal ends 20a and 20b of U-tube 20 to cover the sealed open end 20a and to support these disal ends against any distortion, such as lateral distortion tending to break glass U- tube 20; port or vent means 32f and 1323 extending generally radially from holes 32a and 132:1 in fluid communication with open end 20a of tube 20 for permitting air pressure to be exerted on the outer face of sealing means 44 in seal `4() to force sealing means 44 axially downwardly in FIG. 3 against the liquid mercury surface by air pressure to compensate for any expansion or contraction of the liquid mercury column; clamping means 33 and 133 for detachably clamping blocks 32 and 132 to U-tube distal ends 20a and 20b; and spring 61 and washer 63 telescoped over the upper, distal threaded end 42h of rod 42.

U-tube 20 is shown in its operative position for use in manometer 18 in FIG. l with its pressure port 321 extending generally radially from hole 32a in fluid communication with open end 20a and having outwardly extending tube-like portion for telescopically receiving pressure line 16 during manometer use without using seal 40, spring 61 and washer 63 under cap block 32. It should be readily apparent that seal 40, spring 61 and washer 63 might be assembled in aligned

holes

20a, 32a in the manometer assembled position in FIG. 1 in the same manner as shown in FIG. 3 when the manometer is originally shipped to its user so that seal 40 could provide the same mercury sealing function. Since this construction is readily apparent, it has not been shown in FIG. 1 wherein manometer 18 is shown in its actual operating and pressure measuring position.

Clamping means 133 in FIGS. 2 and 3 includes slit 132s in wood block 132 extending diametrically of hole 132:1 therein supporting open end 20a, and bolt or screw 134, extending generally tangentially of tube 20 at upper end 20a and through the parallel arms of block 132 straddling slit 132s, to permit pulling the two arms together during tightening of screw 134 to clamp them firmly on the distal end of U-tube 20 at closed end 20a to secure block 132 to end 20a of U-tube 20.

Clamping means 33 or 133 holds respectively block 32 or 132 onto tube 20 to prevent axial relative movement between the block and open end 20a so that helical spring `61 will force washer 63 axially downwardly against the top of nut S1 to urge resiliently seal 40 in FIG. 3

axially downwardly with sealing means 44 being urged against the surface of liquid mercury 22. Hence, spring 61 serves as a resilient means operatively connected to seal 40 and through

block

32 or 132 to tube 20 for urging sealing means 44 of seal 40 against liquid mercury 22 sealed in tube 20 by sealing means 44 so that this piston-type sealing means 44 will follow the surface of the mercury during any expansion or contraction thereof to prevent any air leaking past the sealing means toward the mercury tending to break the vacuum therebetween or into the mercury toward sealed and closed tube end 2Gb. It should be readily apparent that good sealing and mercury liquid surface following action by sealing means 44 may be obtainable without using spring 61 or without using

block

32 or 132 but by using only seal 40, but the sealing and following action may be improved by the use of spring 61 and block 32 or 132.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therfore to be considered in all respects as illustrative and not restrictive.

What is claimed and desired to be secured by U.S. Letters Patent is:

1. In combination,

a U-tube with at least one open end with a bore therein;

a removable, internal, piston-type seal telescoped into said Open end and bore to seal said bore, comprising a rod adapted to telescope into said bore,

sealing means on said rod telescopable with said rod into said bore, and

seal control means on said rod for moving said sealing means into sealing position for sealing said bore or into a removable position for removal from said bore;

a block having two parallel holes telescoped over the distal ends of the U-tube to cover said sealed open end and to support said distal ends against distortion;

resilient means operatively connected to said block and seal for urging the sealing means of said seal against liquid sealed in said tube by said sealing means; and

means for holding said block on the U-tube.

2. The combination, as set forth in claim 1, with said holding means comprising clamping means on said block for detachably clamping said block to said distal ends.

3. The combination, as set forth in claim 1, with said U-tube being a manometer tube,

said U-tube containing liquid mercury therein as a liquid sealed in said tube by said sealing means.

4. The combination, as set forth in claim 1, with said sealing means surrounding said rod and being operatively connected to said rod,

said seal control means including seal adjusting means operatively connecting said rod and sealing means and having a manually adjustable portion adjustable from outside said bore for moving said sealing means between said positions while said sealing means is in said bore,

said seal control means including a sleeve means telescoped over said rod and operatively connected to said sealing means and said manually adjustable portion.

5. The combination, as set forth in claim 2, with said block being a shipping block for said manometer,

said clamping means including said block being slit diametrically of the hole therein supporting said open end and having a screw extending generally tangential to the tube at said open end and through said slit.

6. The combination, as set forth in claim 1, with said block including a port extending generally radially from its hole in uid communication with said open end and having means for receiving a pressure line during manometer use when said sealing means and resilient means 30 have been removed.

7. The combination, as set forth in claim 1, with said sealing means comprising two axially aligned annular resilient rubber O-rings telescoped over said rod.

References Cited 45 LOUIS R. PRINCE, Primary Examiner,

I. W. ROSKOS, .Assistant Examiner.

U.S. C1. X.R. 138-89; 206-46 UNITED STATES PATENT OFFICE CERTIFICATE 'OF CORRECTION Patent No. 3,541,858 November 24,

Joseph E. Bonczek It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column l line 36 "its is" should read it is l 2 line 65 "gaskeets" should read gaskets Column 4 li] inthe lowermost sealing member in FIGS should read in th uppermost sealing member 45 for proline 39 "position" s] read positions line 70 "if" should read of Colul lines 2S to 46, the Claim should read as follows l. In combination,

a Utube with at least one open end with a bore therein;

a removable internal piston-type seal telescoped into said open end and bore to seal said bore, comprising a rod adapted to telescope into said bore sealing means on said rod telescopable with said rod into said bore, and

resilient means operatively connected to said block and seal for urging the sealing means of said seal against liquid sealed in said tube by said sealing means and means for holding said block on the U-tube.

2 The Combination, as set forth in claim l with Signed and sealed this 16th day of March 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, Attesting Officer Commissioner of Pate