GB2203406A

GB2203406A - Device for taking a fluid sample near the bottom of a tank

Info

Publication number: GB2203406A
Application number: GB08708963A
Authority: GB
Inventors: Ulrich Dalluge; Christian Rullmann
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 1987-04-14
Filing date: 1987-04-14
Publication date: 1988-10-19
Also published as: GB8708963D0

Abstract

A device for taking a fluid sample near the bottom of a tank comprises a bottle 1 provided with a siphon type inlet pipe 8. A rod 15 provided with two sealing gaskets 20, 21 is slidably connected to the bottle in such a manner that the sealing gaskets close off said inlet pipe 8 and an outlet opening 18 at the top of the bottle when the weight of the bottle is carried by the rod. During operation the device is lowered into a tank by means of a string 17 connected to the rod. When the device has reached the tank bottom the string is slackened, thereby causing the rod to be moved down and allowing fluid to flow from the tank bottom via the inlet pipe into the bottle while air escapes from the bottle via the outlet opening. <IMAGE>

Description

DEVICE FOR TAKING A FLUID SAMPLE NEAR THE BOTTOM OF A TANK The invention relates to a device for taking a fluid sample at a location near the bottom of a fluid storage tank.

With currently available sampling devices it is frequently difficult to draw fluid samples directly from the bottom of a fluid storage tank, such as a cargo tank of a ship, or a water or fuel storage tank.

A major reason for this problem is that currently available sampling devices are difficult to handle because of their complicated design. Furthermore, they are usually operated with two strings which may get entangled when the device is being lowered through the tank, and for proper operation of the device always some clearance is required between the device and the tank bottom.

It is an object of the present invention to remedy the above drawbacks and to provide a sampling device which is simple and economical to use and which can be suspended on one string only.

It is a further object of the invention to provide a sampling device which is automatically activated to take a fluid sample directly above the tank bottom when the device reaches said bottom.

In accordance with the invention these objects are accomplished by a sampling device comprising a bottle provided with a fluid inlet pipe having an inlet opening located outside the bottle at a location near the bottom of the bottle and a downwardly projecting discharge opening located in the interior of the bottle.

The device further comprises a rod which is slidably connected to the bottle and carries a first sealing gasket being located below said discharge opening and a second sealing gasket being located below an outlet opening at the upper end of the bottle. The rod passes through the top of the bottle and is suitable to be connected at the upper end thereof to a hoisting string. The hoisting string pulls the rod in upward direction relative to the bottle when the weight of the device is carried by said string thereby inducing said first and second sealing gasket to close said discharge and outlet opening.

Preferably said inlet pipe is a U-shaped siphon pipe having a pair of downwardly projecting legs, wherein one leg extends along the outer surface of the side wall of the bottle and the other leg passes through the top of the bottle into the interior thereof.

The invention will now be described in more detail with reference to the accompanying drawings, in which: Fig. 1 is a vertical sectional view of a sampling device according to the invention, and Fig. 2 is a cross-section of the device of Fig. 1, taken along line II-II and seen in the direction of the arrows.

Fig. 1 shows a sampling device consisting of a glass bottle 1 which is closed at the upper end thereof by a brass screw cap 2.

The bottle 1 is enclosed in a brass cage 3 with a lead loaded bottom 4 and a bow-shaped carrier handle 5. The cage 3 further comprises a pair of ring halves 6 that are interlocked by a pair of split pins 7. The ring halves 6 surround the screw cap 2 and after removal of the split pins 7 the ring halves 6 can be taken apart thereby allowing easy removal of the screw cap 2 from the bottle 1.

The sampling device further comprises a siphon type inlet pipe 8. The inlet pipe 8 is U-shaped and comprises a pair of downwardly projecting legs 9 and 10. The first leg 9 of the pipe 8 is arranged outside the bottle 1 and comprises at the lower end thereof an inlet opening 11 which is located adjacent to the bottom 4 of the cage 3. The second leg 10 of the inlet pipe 8 passes through, and is rigidly secured to, the screw cap 2. The inlet pipe 8 discharges into the interior of the bottle 4 via a downwardly projecting discharge opening 12 near the bottom of the bottle 4.

A vertically arranged guide tube 13 is rigidly secured to the second leg 10 of the inlet pipe 8 by means of a pair of supports 14. The guide tube 13 serves for guiding a rod 15 through the interior of the bottle 1 such that the rod 15 is able to slide in a vertical direction relative to the bottle 1. The rod 15 is connected at the upper end thereof to a hoisting string 17 and passes via a fluid outlet opening 18 located in the centre of the screw cap 2 into the interior of the bottle 1.

The rod 15 carries two rubber sealing gaskets 20 and 21 which are arranged below said discharge and inlet opening 12 and 18, respectively, in such a manner that the sealing gaskets simultaneously close said openings when the rod 15 is moved in upward direction relative to the bottle 1. The first sealing gasket 20 is mounted on a lateral extension pad 22 which is secured to the lower end of the rod 15. The second sealing gasket 21 is mounted on a collar 23 which sealingly surrounds the rod 15 and is held at a predetermined distance from said extension pad 22 by means of a spacer sleeve 25. The rod 15 passes through a guide opening 27 in the carrier handle 5 and is pressed in downward direction relative to the bottle by a compression spring 28 which is located between said guide opening 27 and collar 23.The spring 28 exerts a downward force to the rod 15 which is smaller than the weight of the empty sampling device.

As can be seen in Fig. 2 the centering of the first sealing gasket 20 on the second leg 10 of the inlet pipe is achieved by providing a semicircular cutout in the second sealing gasket 21 and support collar 23, which cutout corresponds to the curvature of the inlet pipe. With the rod 15 moving up and down, the inlet pipe serves as a guiding device, preventing the first sealing gasket 20 from moving sideward.

The sampling device operates as follows. The device is lowered into a tank from which a fluid sample is to be taken by paying out the string 17. The weight of the lead loaded bottom 4 pulls the bottle 1 down relative to the rod 15. This causes the sealing gaskets 20 and 21 carried by the rod 15 to be pressed against said discharge and outlet opening 12 and 18 thereby sealing off said openings.

As soon as the sampling device has reached the tank bottom (not shown) the hoisting string 17 is slackened and the rod 15 moves down, aided by the spring 28, -thereby causing the sealing gaskets 20 and 21 to move away from the discharge and outlet opening 12 and 18. Now the fluid from the tank can rise through the inlet pipe 8 and flows into the bottle 1, while the air in the bottle 1 is displaced from the bottle 1 via the outlet opening 18.

The escaping air prevents the fluid in the tank from entering the bottle 1 through the outlet opening 18. In this manner the sampled fluid is induced to flow into the bottle via the inlet pipe 8 thereby filling up the bottle 1 with a fluid sample which is drawn directly from the surface of the tank bottom.

When the filled bottle is subsequently pulled up by hauling in the string 17 the two sealing gaskets 20, 21 on the rod 15 are pulled against the openings 12, 18 and thus prevent any fluid to enter into or escape from the bottle 1 on its way up.

The sampling device according to the invention may be used to take fluid samples from the bottom of any type of fluid reservoir.

The device is particularly suitable to detect the presence of water, sludge or solid contaminations at the bottom of a fuel tank.

It will be understood that many variations and modifications may be made in the sampling device hereinbefore described without departing from the concept of the present invention. Accordingly, it should be clearly understood that the embodiment of the device depicted in the accompanying drawing is illustrative only.

Claims

1. A device for taking a fluid sample at a location near the bottom of a fluid storage tank, the device comprising: - a bottle, said bottle being provided at the upper end thereof with an outlet opening, - a fluid inlet pipe having an inlet opening located outside the bottle at a location near the bottom of the bottle and a downwardly projecting discharge opening located in the interior of the bottle, - a rod which is slideably connected to the bottle and carries a first sealing gasket being located below said discharge opening and a second sealing gasket being located below said outlet opening, said rod passing through the top of the bottle and being suitable to be connected at the upper end thereof to a hoisting string, which string pulls the rod in upward direction relative to the bottle when the weight of the device is carried by said string thereby inducing said first and second sealing gasket to close said discharge and outlet opening.

2. The device of claim 1, further comprising a closing cap which is screwed on top of the bottle, said outlet opening being located in the centre of said closing cap.

3. The device of claim 2, wherein the inlet pipe is a U-shaped siphon pipe, said pipe having a pair of downwardly projecting legs, one of said legs being located outside the bottle, the other of said legs extending from a location above the bottle through the closing cap into the interior of the bottle.

4. The device of claim 2, wherein the rod passes through said outlet opening in the centre of the closing cap and said second sealing gasket is co-axially arranged around the rod.

5. The device of claim 3, wherein said inlet pipe is provided with means for guiding the rod in a vertical direction relative to the bottle.

6. The device of claim 5, wherein said first sealing gasket is mounted on a lateral extension pad, which pad is secured to the lower end of the rod.

7. The device of claim 2, wherein the closing cap is provided with a bow-shaped carrier handle, said handle comprising a guide opening through which said rod passes.

8. The device of claim 7, wherein a compression spring is arranged around the rod at a location below the guide opening in the carrier handle, said spring exerting a downward force to the rod, which force is smaller than the weight of the empty bottle.

9. A sampling device according to claim 1, substantially as described hereinbefore with reference to the accompanying drawing.