US2551645A

US2551645A - Multiple pipe-testing machine

Info

Publication number: US2551645A
Application number: US542636A
Authority: US
Inventors: Joseph F Stadelman
Original assignee: TAYLOR WILSON Manufacturing CO
Current assignee: TAYLOR WILSON Manufacturing CO
Priority date: 1944-06-29
Filing date: 1944-06-29
Publication date: 1951-05-08
Anticipated expiration: 1968-05-08

Description

May 8, 1951 J. F. STADELMAN MULTIPLE PIPE-TESTING MACHINE 7 Sheets-Sheet 1 Filed June 29, 1944 INVENTOR QWN m wN

May 8, 1951 J. F. STADELMAN MULTIPLE PIPE-TESTING MACHINE 7 Sheets-Sheet 2 Filed June 29, 1944 R mwu 1 F. A

v Mme 0f) xvii May 8, 1951 J. F. STADELMAN MULTIPLE PIPE-TESTING MACHINE 7 Sheets-Sheet 5 Filed June 29, 1944 y 1951 J. F. STADELMAN 2,551,645

MULTIPLE PIPE-TESTING MACHINE Filed June 29, 1944 7 Sheets-Sheet 4 INVENTOR 45 Joseph l TJfaae/ma/r @A M,M 99w;-

May 8, 1951 J. F. STADELMAN MULTIPLE PIPE-TESTING MACHINE '7 Sheets-Sheet 5 Filed June 29, 1944 May 8, 1951 J. F. STADELMAN MULTIPLE PIPE-TESTING MACHINE 7 Sheets-Sheet 6 Joseph A'ffade/man Filed Juneg 29, 1944 May 8, 1951 J. F, STADELMAN MULTIPLE PIPE-TESTING MACHINE 7 Sheets-Sheet 7 Filed June 29, 1944 MWEE s NWN INVENTOR 23 251946077 QWN NWN QWNN Patented May 8, 1951 UNITED STATES MULTIPLE PIPE-TESTING MACHINE Joseph F. Stadelman, Mount Lebanon Township,

Allegheny County, Pa., assignor to Taylor- Wilson Manufacturing Company,

McKees Rocks, Pa., a corporation of Pennsylvania Application June 29, 1944, Serial No. 542,636

10 Claims.

This invention relates to the testing of pipe and, in particular, to a machine and method for testing a plurality of pipe lengths simultaneously.

Pipe and tubes made by diiferent manufacturing processes must be subjected to a hydrostatic shop test. Such a test is usually made by disposing a length of pipe between movable heads and admitting fluid, such as water, under a predetermined pressure, to the interior thereof. While this method and the apparatus which has been developed therefor are generally satisfactory, the time required in testing pipe lengths individually is such that the cost thereof is a substantial item in the overall cost of the pipe. The object of my invention, accordingly, is to provide for the simultaneous testing of a plurality of pipe lengths, thus reducing the time required per length of pipe and the unit cost of the testing operation.

In a preferred embodiment and practice of the invention, I provide apparatus including a main frame having carriages at the ends thereof fitted with boxes adapted to engage the ends of a group of pipe lengths disposed side-by-side spaced parallel relation. The pipe lengths are preferably carried through the apparatus on a transfer conveyor. I also provide a loading conveyor and means for delivering pipe lengths individually thereto. The loading conveyor is so constructed and positioned relative to the transfer conveyor that it may be caused to deposit thereon a plurality of pipe lengths arranged in a group for simultaneous testing. A plurality of pipe lengths, having been arranged in a group, are moved through the machine along a predetermined path. Their progress through the machine is arrested at a given point and they are moved to testing position wherein the several pipe lengths of the group are simultaneously subjected to a hydrostatic test by the admission to the interior thereof of water under suitable pressure. Thereafter, the progress of the group of pipe lengths through the machine is resumed. Pipe lengths exhibiting defects under the hydrostatic test are separated from the remainder of the group and the latter are then discharged into a suitable receiving means.

Further novel features and advantages of the invention may be fully comprehended by consideration of the following detailed description referring to the accompanying drawings illustrating a preferred embodiment of the apparatus.

In the drawings:

Figure 1 is a plan view of the apparatus as a i whole;

Figure 2 is a partial plan View showing a portion of Figure 1 to enlarged scale;

Figure 3 is a partial section taken along the plane of line I-II-III of Figure 1; I

Figure 4 is a partial section taken along the plane of line IV-IV of Figure 3;

Figure 5 is a partial section similar to Figure 3, showing a portion of the latter to enlarged scale;

Figure 6 is a partial plan view corresponding to Figure 5;

Figure 7 is a sectional view taken along the plane of line VIIVII of Figure 5 showing a detail;

Figures 8 and 9 are transverse sections taken along the planes of lines VIIIVIII and IXIX of Figure 1, respectively;

Figures 10 and 11 are partial sections taken along the planes of lines XX and XI-XI of Figure 2, respectively;

Figure 12 is a partial section taken along the plane of line XIL-XII of Figure 2;

Figure 13 is a partial section taken along the lane of line XIII-XIII of Figure 1;

Figure 14 is a section taken along the plane of line XIV XIV of Figure 13, with parts shown in plan; and

Figure 15 is a view similar to Figure 13 showing a modification.

Referring in detail to the drawings, the apparatus comprises a main frame It including upper and lower longitudinal members I! and i2 extending between spaced cross members i3. As shown, the longitudinal members are made up of pipe lengths it provided with terminal brackets i5 and tie rods I6 securing the brackets to the pipe lengths. The cross members l3 are composed of spaced channels I! and side plates [8 secured to the flanges thereof. Through bolts as and screws 28 secure the brackets l5 to the cross members. The latter are secured to a suitable bed-plate or foundation 2!.

Carriages

22 and 23 disposed adjacent the cross members 13 are reciprocable longitudinally of the frame it for a limited distance. The carriages are provided with a plurality of boxes 2 3 and 25 adapted to receive the ends of a plurality of pipe lengths 26 to be tested. Further details of the construction and operation of the carriages and associated parts will be described later.

The pipe lengths 26 are initially disposed on entering skids 21 from which they are successively delivered individually to a loading conveyor 28. When a plurality of pipe lengths have been disposed in spaced parallel relation on the loading conveyor, they are deposited as a group on a transfer conveyor 29 which is adapted to move them through the machine and between the

carriages

22 and 23, maintaining their relative positions in spaced parallelism.

The loading conveyor 28 comprises chains 30 trained around drive sprockets 3! and idler sprockets 32. The sprockets 3| are mounted on a shaft 33 journaled in bearings 34 and driven from an intermediate shaft by a chain-andsprocket drive 36. The shaft 35 is driven by a motor 3'! through speed-reduction gearing 38 and a spindle 39 provided with universal couplings at each end. The sprockets 32 are secured to shafts 32a journaled in bearings 32b.

The upper runs of the chains 36 travel in channel guides 40. These guides are supported by angle brackets M on longitudinal beams 42. The beams 42 rest on cross beams 43 and are secured thereto, constituting therewith a rigid frame. This frame has guided vertical movement, being provided with downwardly extending posts 44 at each corner, reciprocable in fixed cylindrical guides 45.

Vertical movement of the frame of the loading conveyor is effected by a pneumatic or hydraulic cylinder and piston 46 operating a pull rod 4?. Spaced rock shafts 48 parallel to and substantially in vertical alignment with two of the beams 43, have arms 49 pivoted to the rod 41. The shafts 48 are journaled in bearings 48a and have cams 50 thereon. Rollers 5| journaled in housings 52 secured to the beams 43 above the shafts 48 rest on the earns 50. By this construction, the frame 42-43 of the loading conveyor may be raised or lowered. Figures 3 and 4 show it in raised position. The

bearings

32b and 34 for the shafts 32a and 33 are carried on the beams 43, as shown in Figures 3 and 5, so that the whole conveyor moves bodily as a unit.

The chains 30 have V-blocks 53 secured thereto in spaced relation adapted to receive pipe lengths 26 successively from the skids 21. As shown in Figures 3 and 5, the skids 21 have shoulders 21a adjacent their lower ends which serve to arrest pipe lengths deposited on the skids. The pipe lengths may be deposited on the skids in bundles by an overhead crane and then distributed by hand over the length of the skids or may be delivered individually from a cooling bed disposed adjacent the welding mill. The pipe length adjacent the shoulders 21a of the skids 2'! is lifted thereover by vertically reciprocable pusher bars 54, having heads 55 at the upper ends thereof which are generally V-shaped. The pusher bars are operated by forked levers 56 pivoted on bearing pedestals 57. The bifurcated ends of the levers 55 are pivotally connected to the pusher bars 54 by links 58 and through pins 59. The bars 54 are slidable in tubular guides 59 mounted on the beams 43 and are normally held in their lowermost position by compression springs 6!. The guides 60 have slots 66a to accommodate the pins 59. Cams 62 on the shafts 32a cooperate with rollers 63 rotatably carried between the spaced branches of the levers 56. The pusher bars 54 are thus reciprocated vertically in timed relation to the angular movement of the sprockets 32. The construction of the parts is such that the pusher bars, after lifting the pipe length disposed against the shoulders 21a of the skids 21, will deposit it on the next set of V-blocks 53 coming around the sprockets 32 as the pusher bars descend. This method of operation is clearly indicated in chain lines in Figure 5. It will be understood that when the pipe length disposed against the shoulders 2'la has been raised clear thereof, it rolls down the heads 55 into position for deposit on the V-blocks as the pusher bars descend. The pipe lengths on the skids 21, of course, roll down against the shoulders 21a as soon as the pipe length formerly abutting thereagainst has been lifted clear. It will be apparent from the foregoing that the loading conveyor 28 4 serves to pick up pipe lengths successively from the skids 2'! and arrange them in a group, in spaced parallel relation. The skids 2'! are adjustable longitudinally to permit pipe of different sizes to be properly positioned for engagement by the pusher-bar heads.

The transfer conveyor 29 comprises a plurality of chains 54 trained around driving sprockets E5 and idler sprockets 6B. The upper runs of the chains traverse channel guides 61 and are provided with V-blocks 68 spaced therealong on the same centers as the blocks 53 of chains 35!. As shown in Figure 3, guides 61 are supported (by any convenient means, not shown) at an elevation such that when the loading conveyor is in its elevated position, the pipe lengths 25 on the V-blocks 53 thereof clear the V-blocks 68. The sprockets G5 are secured to a shaft 69 journaled in bearings 70 and driven by a motor ll through speed-reduction gearing :2. The sprockets 56 are secured to shafts 66a journaled in bearings 66?) in the same vertical plane with the shafts 32a.

It will thus be apparent that the loading conveyor 28 partially overlaps the transfer conveyor 29. After the loading conveyor has been operated long enough to fill the V-blocks on the upper runs of the chains 33 with pipe lengths, as shown in Figure 3, the chains 30 may be stopped with their V-blocks in alignment with those on the chains 64 and the loading conveyor bodily lowered by operation of the pull rod 41, whereby the group of pipe lengths 26 on the loading conveyor is simultaneously deposited on the transfer conveyor. The transfer conveyor is then operated to move the group of pipe lengths to a position within the frame it), as shown in chain lines in Figure 1. The loading conveyor 28 is then elevated and operation thereof is resumed.

When the pipe lengths have been moved into the testing machine on the transfer conveyor, the latter is stopped when the pipe lengths are in vertical alignment with the

boxes

24 and 25 but on a level below them. In order to raise the pipe lengths into exact axial alignment with the boxes, a liftable table 13 including longitudinal members 14 and cross members 15 is disposed within the table [0. The frame i3 has a guided vertical movement by virtue of posts H3 depending therefrom and received in tubular guides 11. Rock shafts 18 have arms 19 provided with rollers adapted to engage bearing plates 8| on the underside of the cross members 15. The shafts 18 are actuated by a pull rod 82 pivoted to arms 83 secured to the shafts. A hydraulic or pneumatic cylinder and piston 84 has its piston rod connected to the pull rod 82. It will be apparent that by properly rotating the rock shafts 18 the table 73 may be caused to move from the position shown in solid lines in Figure 8 to the position shown in chain lines. The table will, of course, be lowered to the position shown in chain lines when the group of pipe lengths deposited on the transfer conveyor by the loading conveyor is being moved into position.

The cross members 15 of the table 13 have V- blocks 85 spaced therealong on the same centers as the V-blocks 63. When the table 13 is in its lower position, the V-blocks 85 are below the path of the pipe lengths positioned on the V- blocks 68 of the transfer conveyor. When the latter has been arrested with the group of pipe lengths in vertical alignment with the V-blocks 5 85, the pipe lengths will be picked up thereby and lifted off of the V-blocks 68 when the table 13 is raised. When the table '53 is in elevated position, the pipe lengths resting on the V- blocks 85 are in axial alignment with the

boxes

24 and 25 of the

carriages

22 and 23.

Hold-down beams 86 extend across the frame I between brackets Ia on the upper longitudinal member II. The beams 88 are efiective, as shown in Figure 9, to prevent bowing of the pipe lengths under the fluid pressure on the ends of the pipe wall when subjected to hydrostatic testing in the manner to be described later. When the table 13 is in raised position, the pipe lengths on the V-blocks 85 thereof are adapted to be engaged by gripper plungers 87. The plungers 81 are reciprocable in cylinders 88 spaced along a transverse supporting beam 89 and are actuated by compression springs (not shown) in the cylinders. The beam 8?; like the beams 86 extends between the upper longitudinal members II of the frame it. The plungers 8'1 may be positively withdrawn by a slide bar 90 extending through the cylinders 88 adjacent the bottom thereof and having wedges 9i elfective to raise the plungers against the force of the springs. The slide bar 99 is actuated by a hydraulic or pneumatic cylinder and piston 92. The function of the plungers 81 is to obtain a frictional grip on the pipe lengths resting on the V-blocks 85 to prevent axial shifting thereof on withdrawal of the

carriages

22 and 23 after the completion of a hydrostatic test.

The

carriages

22 and 23 are generally similar, the carriage 22 being shown in detail in Figures 2 and 10. Each carriage includes a bridge member having wheel housings 94 at each end. The bridge member is composed of spaced upper and lower channels 25 connected together by side plates 96. The wheel housings have wheels 91 journaled therein traversing rails 98 resting on the foundation or bed-plate 2i. Screws 99 extend outwardly from each end of the bridge member as, being secured tiereto by nuts Isl]. The screws extend through worm gear housings IIJI secured to the cross members I3 of the frame it and into closed sleeves I92 carried thereby. Worm gears H33 journaled in the housings IGI have their bores threaded to receive the screws 29 and are driven by worms Hi4 secured on shafts 555. The shafts I95 are coupled to driving shafts its journaled in bearings It? on the cross-members. Motors @538 mounted on the cross members drive the shafts 655 through belt-and-pulley drives E632. it will be apparent that the

carriages

22 and 23 may be advanced toward each other and retracted by operating the motors I08 in the proper direction.

The boxes 2d of the carriage 22 are mounted on hollow shafts I is extending through the bridge member 93 and into cylinders III extending through the cross member I3. The boxes are seated in holders H2 secured to the ends of the shafts ill? by screws H3, being held in place by clamps H4. The clamps are secured by studs I i5 threaded into the holders. The shafts I It are secured to the bridge member 93 by nuts HE turned on externally threaded portions thereof. The shafts are slidable through sleeve bearings Ilia in the cylinders ill, the latter being provided with stuffing boxes Ill to seal the joints. The cylinders have pipe connections I I8 for supplying fluid under pressure to the interior of pipe lengths engaged by the boxes 24. Individual shut-oil? valves (not shown) are disposed in each of the connections II8 for a purpose which will appear later. Further details of the boxes 24 will be referred to in the description of the boxes 25, one of which is shown to enlarged scale in Figure 13.

The boxes 25 are disposed in holders H9 generally similar to those shown at H2 by clamps l2ii secured by studs I2I. The holders H9 are secured to pistons I22 reciprocable in hydraulic push-up cylinders I23 spaced along the carriage 23 and extending through the inner side plate 53 thereof. The cylinders are secured to a plate I22 by screws I25 passing through flanges I23a integral with the cylinders. The plate I24 is secured to the side plate 96 of the carriage in any convenient manner.

The boxes 2 and 25, as shown in Figure 13, have insert rings 5 26 and [2! provided with sealing rings I28 and I29. Radial passages I30 and longitudinal passages ISI in the insert I21 provide communication between the interior thereof and the interior and exterior of the ring I28. The inner surface of the sealing ring I28 is adapted to engage the exterior of a pipe end entering the box 25. The pressure applied to the fluid in the pipe for the purpose of subjecting it to a hydrostatic test is thus applied also to both the inner'and outer surfaces of the ring I28 tend: ing to set them against the pipe and the interior of the box, establishing a tight seal effective to prevent leakage. The pipe end abuts the insert I2! and the sealing ring I29, which is subject to the pressure of engagement therebetween, seals the joint between the box and holder. Although not shown in Figure 12, the boxes 24 have the same construction as the boxes 25 in respect to the inserts l2ia and I21, the sealing rings I28 and !29 and the passages I30 and I3I.

Water is supplied to the cylinders I23 through pipes I 32 connected to a manifold which is supplied with water under the same pressure as that delivered to the pipe lengths through connections I I8 for testing. The pistons I22 are thereby caused to exert a force on the holders II9 substantially equal and opposite to the outward pressure exerted on the holders by the pressure of the water in the pipe lengths.

Guide rods I33 secured to lugs E34 extending laterally from the holders I I9 pass through holes in the flange I23a and lugs I23?) of each cylinder and are secured to a crosshead 534a at the outer end thereof. The crossheads I34a are normally held against the outer ends of the cylinders I23 by spring cushions I35 mounted in the outer side plate 96 of the carriage 23. Each cushion I35 includes a cylinder I36 extending through the side plate 96. The cylinder has a collar I36a welded thereto which is secured to the plate l8 by bolts 23612. The cylinder has a closure I31 at its outer end adapted to receive a threaded bushing I38 having a flange I39 inside the cylinder anda lock nut 380; threaded thereon outside the cylinder. A plunger I49 slidable in the bushing I38 has a head I4! abutting the crosshead I340, and is threaded at its outer end to receive adjusting nuts I22. A washer I 42a is disposed between the nuts I42 and the bushing I38. A compression spring I43 bears against the head It! at one end and at the other end against a collar IM slidable on the plunger and abutting the flange I39 of the bushing I38.

The spring cushions I35 provide yieldable back-ups for the holders H9 to compensate for slight variations in the length of the pipe being tested. They also serve to cushion the advance movement of the

carriages

22 and 23 as the ends of the pipe lengths enter the

boxes

25 and 25. It will be apparent that the cushions are compressed as the pipe ends bottom on the inserts 12! of the

boxes

24 and 25, the amount of compression in each instance depending on the exact length of the pipe engaged by a particular pair of boxes. The provision of the cushions makes it unnecessary to stop the advance of the carriag'es with any great precision since a slight variation in their final positions will not materially aifect the pressure exerted by the cushlOIlS.

Figure illustrates a block 155 which may be substituted for the

boxes

24 and 25 if it is desired that the full length of the pipe be subjected to the hydrostatic test. It will be obvious that with the boxes 2d and 25, that portion of the pipe length within the boxes is confined thereby and is thus not subjected to the bursting stress exerted on the remainder of the pipe length. The block I has an annular groove I 15 provided with a sealing ring MT. The blocks I45 are adapted to be secured in the holders 1 l2 and i as inv the same manner as the

boxes

24 and 25.

The operation of the apparatus described will be apparent from the foregoing. In order to explain the method of my invention, a complete operating cycle will be described. When the apparatus described is first placed in operation, pipe lengths are delivered to the skids 27 and manually arranged side by side, as shown in Figure 3. The loading conveyor 28 is then starts with the frame 42-43 thereof in raised position. Pipe lengths. delivered successively from the skids 27 by the pusher bars 54 are placed on the V-blocks 53 of the loading conveyor and when a pipe length has been placed on each set of aligned V blocks on the upper run of the chains 32, the loading conveyor is lowered to transfer the group of pipe lengths arranged in spaced parallel relation to the V-blocks 68 of the transfer conveyor 29.

The transfer conveyor is then started to move the pipe lengths on the V-blocks 58 to positions in vertical alignment with the axes of the

boxes

24 and 25 of the

carriages

22 and 23. While the group of pipe lengths is traveling on the transfer conveyor and is being tested as will be described shortly, the loading conveyor 28 is again raised and started into operation again, to provide a second group of pipe lengths arranged in spaced parallel relation.

Elevation of the table 13 causes the pipe lengths to be picked up from the V-b1ocks 68 and brought into exact alignment with the

boxes

24 and 25. The

carriages

22 and 23 are then advanced so that the boxes are disposed over the ends of the pipe lengths. The carriages are preferably operated so that the ends of the pipe lengths are first seated against the inner faces of the boxes 25. As the boxes 25 are engaged by the other ends of the lengths, the cushions 35 will be compresse: by those of the pipe lengths which are in excess of the nominal length, thus compensating for minor variations in length.

The pipe lengths having been brought into testing position, water under the desired pressure is admitted to the interior thereof through pipe connections H8 by operating a main valve (not shown). The beams prevent the pipe lengths from bowing upwardly under the pressure on the end of the pipe wall and thus eliznmate the hazard to the workmen resulting from a pipe lengths springing out of testing position.

The water supplied to the pipe lengths compresses any air trapped therein. The pressure of the water or air is communicated through the

passages

33 and 13! in the insert rings E26 and i2! to the sealing rings I28 and 129, thereby tightly sealing all oints through which leakage might otherwise occur. At the same time, water under the same pressure as that supplied to the pipe lengths is admitted to the cylinders I23 whereby the pistons I22 oppose the force exerted by the pressure of the fluid on the holders H9. An outlet 136a is provided in each of the boxes 25 and blocks H15 to permit the air trapped in the pipe lengths to be purged through a suitable control valve and pipe connections, if desired.

If any pipe length of the group has a defect in that portion between the sealing rings 128 of the

boxes

24 and 25, the tr pped will soon leak out and water will then be discharged, giving the operator a visible indication of t e defeet. He thereupon closes the individual valve (not shown) in the connection H8 supplying water to the defective pipe. The latter is thus cut out of the group, thereby permitting the maximum required pressure to be built up on the water in the remaining pipe lengths.

After the desired pressure has been maintained on the pipe lengths for the required interval of time, the main supply valve is closed and a drain valve (not shown) is opened to permit the water in the pipe lengths to run out. The slide bar is then operated to permit the plungers 81 to the pipe lengths to hold. them against axial displacement on retraction of the carriages as a result of the frictional engagement between the boxes and the ends of the lengths. The motors l are then operated to pull back the carriages, ai er the pressure in the pipe lengths has been relieved. The slide bar 95 is then operated to raise the plungers 8i and the table i3 is lowered to restore the pipe lengths to the \'blocks 68 on the chains of the transfer conveyor 29.

During the regress of the actual testing operation, the loading conveyor will have operated to place anot. er group of pipe lengths on the transfer conveyor. Continued operation 01' the latter, therefor", will advance the first group toward the disc. i "he machine and bring the next group into position for elevation into alignment with the boxes E i and 25. Cradles M8 on discharge side of the machine have liftable skids f or collecting defective pipe lengths as they roll 6 The skids M9 are normally in position to carry pipe lengths which have successi'ully withstood the hydrostatic test, over the cradles H28 and into similar cradles adjacent thereto (not shown) from which the tested pipe lengths may be removed in bunan overhead crane.

It will be evident from the foregoing that the method of my invention, in brief, includes the a group of pipe lengths in on, depositing them simulnsfer conveyor for movement -cd path to testing position and, after completion of the test, by continued movement along the same path, the delivery of the tested lengths to a receiving means.

numerous advantc the first place, the into test a much largcr known heretofore. The entire test apparatus can be operated by one man. An additional Workman is required to arrange the entering pipe lengths parallel on the skids 27. A plurality of pipe lengths (8 in the embodiment shown) are subjected to a hydrostatic test simultaneously by operating a single control valve. The boxes engaging the ends of the pipe lengths are of the outside-packing type so that endwise pressure on the pipe lengths is not relied on to seal against leaage under the testing pressure. The boxes may easily be changed to accommodate different sizes of pipe. The boxes and their cylinders I23 are all secured to the plate i2 1 and. may thus be removed and replaced as a unit. While there is little tendency of the pipe lengths to bow since the endwise pressure thereon is small, the holddown beams 86 preclude any substantial bowing, and thus contribute to greater safety of the op erators.

The apparatus operates at a high rate of efficiency. While one group of pipe lengths is under test, the next is being arranged and deposited on the transfer conveyor, ready for testing in the next operating cycle Without loss of time. The apparatus is Well adapted to automatic control, thereby enabling the operator to confine his attention to a relatively few functions such as spotting the defective pipe lengths and operating the liftable skids I49 to deliver them into the proper cradles. The individual control valves on the pipe connections to the several boxes 2t. permit the testing of a group of pipe lengths to be completed even though one length is defective, since any leaky pipe length may be isolated from the remainder and the testing of the latter carried onto completion.

Although I have illustrated and described only a preferred embodiment and practice with a mod ification of one detail, it will be recognized that changes in the construction and operation disclosed may be made Without departing from the spirit of the invention or the scope of the rap-- pended claims.

I claim:

1. A multiple pipe-testing machine comprising a frame, a transfer conveyor adapted to carry pipe lengths disposed thereon in spaced parallel relation, across said frame, a lifting table intermediate the sides of the frame adapted to raise a group of said lengths from said conveyor to testing position, and carriages adjacent the ends of the frame movable endvvise of the lengths and having boxes spaced therealong adapted to engage the ends of the lengths and supply testing fluid under pressure thereto.

A multiple pipe-testing machine comprising a frame, a transfer conveyor adapted to carry pipe lengths disposed thereon in spaced parallel relation, across said frame, a lifting table intermediate the sides of the frame adapted to raise a group of said lengths from said conveyor to testing position, carriages adjacent the ends of the frame movable endvvise of the lengths and having boxes spaced therealong adapted to en gage the ends of the lengths and supply testing fluid under pressure thereto, and means for depositing a plurality of pipe lengths simultaneously on said conveyor in spaced parallel relation.

3. A multiple pipe-testing machine comprising a frame, a transfer conveyor adapted to carry pipe lengths disposed thereon in spaced parallel relation, across said frame, means intermediate the sides of the frame and adjacent the ends thereof for subjecting a group of said lengths simultaneously to a hydrostatic test, a loading conveyor adjacent the entering side of the frame, means for placing pipe lengths successively on said loading conveyor and means whereby said loading conveyor simultaneously deposits a group of lengths disposed in spaced parallel relation on said transfer conveyor.

4. A multiple pipe-testing machine comprising a frame, a transfer conveyor adapted to carry pipe lengths disposed thereon in spaced parallel relation, across said frame, means intermediate the sides of the frame and adjacent the ends thereof for subjecting a group of said lengths simultaneously to a hydrostatic test, a loading conveyor adjacent the entering side of the frame, means for placing pipe lengths successively on said loading conveyor and means for raising and lowering said loading conveyor whereby a group of pipe lengths disposed thereon in spaced parallel relation may be simultaneously deposited on said transfer conveyor.

5. A multiple pipe-testing machine comprising a frame, a transfer conveyor adapted to carry pipe lengths disposed thereon in spaced parallel relation, across said frame, means intermediate the sides of the frame and adjacent the ends thereof for subjecting a group of said lengths simultaneously to a hydrostatic test, a loading conveyor adjacent the entering side of the frame, means for placing pipe lengths successively on said loading conveyor, said loading conveyor partially overlapping said transfer conveyor and being movable vertically whereby to deposit simultaneously on said transfer conveyor a group of pipe lengths arranged in spaced parallel relation.

6. A multiple pipe-testing machine comprising a frame, a transfer conveyor adapted to carry pipe lengths disposed thereon in spaced parallel relation, across said frame, means intermediate the sides of the frame and adjacent the ends thereof for subjecting a group of said lengths simultaneously to a hydrostatic test, a loading conveyor adjacent the entering side of the frame, means for placing pipe lengths successively on said loading conveyor, said conveyors comprising spaced chains traveling over guide and driving sprockets, the loading conveyor chains extending alongside the transfer conveyor chains for a portion of the width of the frame, and means for raising and lowering the loading conveyor whereby a plurality of pipe lengths placed successively thereon may be deposited simultaneously on said transfer conveyor.

7. A multiple pipe-testing machine comprising a frame, a transfer conveyor adapted to carry pipe lengths disposed thereon in spaced parallel relation, across said frame, a lifting table intermediate the sides of said frame adapted to raise a group of said lengths from said conveyor to testing position, movable fluid-supply means adjacent the ends of the frame adapted to engage the ends of said lengths when in testing position, and gripper means adapted to engage the lengths intermediate their ends.

8. A multiple pipe-testing machine comprising a frame, a transfer conveyor adapted to carry pipe lengths disposed thereon in spaced parallel relation, across said frame, a lifting table intermediate the sides of the frame adapted to raise a group of said lengths from said conveyor to testing position, hold-down beams spaced along the frame and disposed above the testing position, and movable fluid-supply means adjacent the ends of the frame adapted to engage the ends of said lengths when in said position.

9. In a machine adapted to hydrostatically test 11 a plurality of parallel lengths of pipe in groups of substantially the same length, said machine having opposed retractable means adapted to engage the respective ends of said lengths of pipe to subject them to hydrostatic pressure, the improvement comprising, a plurality of holders on each of said retractable means corresponding in number to said plurality of parallel lengths of pipe, a box in each of said holders, said box having a flared opening for receiving one end of a length of said pipe, said opening communicating with a cylindrical chamber in said box, an annular insert in said chamber, a sealin ring positioned over the surface of said insert adjacent said opening and normal to the axis thereof, said sealing ring extending over the adjacent corners of said insert and being substantially Ushaped in cross section, and passages connecting the edges of said sealing ring around said insert to the source of fluid for said hydrostatic pressure, whereby when said end of said length of pipe is inserted in said box, sealing ring prevents leakage of said fluid through said box.

10. A machine for hydrostatically testing lengths of pipe, comprising, a substantially rectangular frame, a plurality of conveying means operating transverse to said frame, each said conveying means having conveying elements in interleaved relation with the conveying elements of the other conveying means, said elements on each conveying means being moved in registry with one another, at least one block on each conveying element of each conveying means, said blocks on each conveying means being in longitudinal registry and adapt..d to hold a length of .5

pipe to be hydrostatically tested, means for verti-- cally moving said conveying means relative one another when the respective blocks on the respective conveying elements of each are in longitudinal registry to transfer a length of pipe from one of said conveying means to the other of said conveying means, a verticall reciprocating table within said frame, at least one pair of blocks on said table in longitudinal registry and in interleaved relation with the blocks on one of said conveying means, retractable carriage heads adapted to engage said len ths of pipe and complete a hydrostatic testing circuit, and means for vertically moving said table and one of said conveying means relative one another when the respective blocks on each are in registry to transfer a length of pipe from said last-mentioned conveying means to said table, and means for moving said table vertically into a position in which said length of pipe may be engaged by said carriage heads.

JOSEPH F. STADELMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,101,932 Hooker June 30, 1914 1,325,747 McGrath Dec. 23, 1919 1,613,150 ZOIe Jan. 4, 1927 1,876,711 Mahla Sept. 13, 1932 1,973,674 Rosenkranz Sept. 11, 1934 2,017,393 Boax et al Oct. 15, 1935 2,231,807 Hybarger Feb. 11, 1941 FOREIGN PATENTS Number Country Date 401,621 Great Britain Nov. 16, 1933 551,566 Great Britain Mar. 1, 1943