US2305023A - Sampling device - Google Patents

Description

Dec. 15, 1942. T, v MOORE 2,305,023,V

' SAMPLING DEVICE Filed Feb. 7, 1941 ATTORNEY Patented Dec. 15, 1942 SAMPLING DEVICE Thomas V. Moore, Houston, Tex., assgnor to Standard Oil Development Company, a corporation of Delaware `Application February 7, 1941, `Serial No. 377,828

3 Claims.

The present invention is directed to a device for taking samples of uid owing in a conduit.

It is an object of the present invention to devise a sampling means for a flowing stream of fluid which utilizes the energy of the fluid for its operation.

A further object of the present invention is to provide a means for diverting from a flowing stream a sample, the size of which is proportional to the amount of fluid forming the stream.

Other objects and advantages of the present inventionV may be seen from the following description taken in conjunction with the drawing in which the sole figure is an elevation, partly in section, of a preferred modification of the present invention.

,The device of the present invention provides a means for diverting a definite portion of a `stream 'of iluid flowing in a conduit. It depends for its operation upon the known fact that if two conduits containing orifice plates, across which most of the pressure drop in a conduit occurs, are connected in parallel, the ratio of the iiuid flowing in each of the lines is constant.

It is known that, if the main line has one orice plate, the ow can be represented by the equation Q Cx/ where Q is the flow, C is \/2g times the orifice coeiiicient and h the pressure drop across the oriiice. If the conduit is provided with a bypass line having several plates in series, the following equation is true:

l q= VTT W @+C-22+@ Where q is the flow of fluid through the bypass line, C1, Cz, C3 etc. are \/2g times the plate coelcients, and h the total pressure drop across all of the plates in the bypass line. If the resistance in the bypass line'is small compared to the drop across the orifice plates, the total pressure drop across all of the orifice plates in the bypass line is equal to the pressure drop across the orifice plate in the main conduit. Under such conditions, the following equation is true:

1 l l l q Vasi-w+@ Q C which, in turn, equals a constant.

The device of the present invention utilizes the above discussed principle.

Referring specifically to the drawing, a casing I I is provided with a bore I2 and counterbore I3 which together comprise the sampling chamber. Main conduit I4 has arranged therein orice plate I5. The upstream side is connected to bore I2 by a line I6, and the downstream side is connected to the bore by line I'I. Orifice plate I8 is positioned in line I'I.

The openings from line i6 into bore I2 and all other similar openings are preferably made in the form of sharp edge orifices in order that the fluid circuit will in effect be a line'with a number of orifice plates in series. Arranged within bore I2 is piston valve I9 which is shaped so that it nts slidingly within the bore. The center portion of the piston is recessed. Arranged within counter bore I3 for sliding movement therein is piston 2U which has attached thereto longitudinal extending tubular portion 2| provided with inwardly projecting shoulders 22. Longitudinally extending rod 23 is secured to `piston valve I9 and is provided with serially arranged lugs 24 and 25. Lug 25 is of greater lateral` dimensions than the opening between shoulder 22 and is arranged in the cavity of tubular member 2| between the piston 20 and shoulder 22. Y

A trigger 26 having attached thereto leaf spring 2'I is arranged within the counterbore of the sampling chamber to cooperate with lug 24 and is secured to the casing of the sampling chamber by pivot 28. A spring 29 has one end secured to casing II and the other to piston valve I9. A conduit 30 fluidly connects the end of counterbore I3 with bore I2 at a point adjacent the connection of line I6 thereto. Conduit 3I is also arranged for conducting iiuid from the bore to sample receiver 32.

When the parts of the device are in the position shown in the drawing, fluid is free to flow from main conduit I4 through branch conduit I6 into bore I2 and the fluid passing around the recessed portion of piston valve I9 is conducted by line 30 into the upper portion of counterbore II. The pressure of this uid forces piston 2u downwardly which, in turn, forces fluid through line I'I, orice I8, back into the main conduit I4. When piston 20 has traveled downwardly a predetermined distance, tubular member 2| will release lug 24 from catch 26 allowing spring 29 to pull piston valve I9 from its open to its closed position.` When valve I9 closes, its upper enlarged end prevents the entrance of iluid by line I6 and the recessed portion allows lines 30 and Y open or closed container, as desired, but must be maintained at a pressure substantially below that in conduit I4.

When piston 20 has moved upwardly a predetermined distance, shoulder 22 engages lug 25 and piston valve I9 is drawn upwardly with piston 20. The movement of the piston upwardly continues until valve I9 again uncovers the outlet of line I6 which allows the iiuid from the upstrea .i side of conduit I4 to enter in bore I2. However, the device is so proportioned that when the outlet of line I6 is uncovered, the outlet to line 3| has been covered, and trigger 26 is in position t0 engage lug 24 and hold Vvalve I9 in. an open position. The device is accordingly in position 'to repeat its cycle.

In order to increase the speed of the cycle, fluid from the downstream side of conduit I5 may be allowed to flow into the sample container without passing through orice I8. However, to allowsuch a flow of uid, a bypass 33 has been provided viin line I'I leading around orifice plate I8. Bypass 33 contains check valve 34 which allows the flow of fluid from th'e downstream side of the conduit into' the sampling chamber, but prevents the flow of iluid in the reverse direction,

In order to obtain a more satisfactory operation, piston valve I9 and piston .20 should not only be accurately ground to t into the sampling chamber, but, in addition, piston 2D should have an average density approximately equal to that of the sampled liquid in order to minimize the friction of the piston motion. One method of plate I8 is proportional to the main vstream of.

fluid owing through line I4 provided with orioe plate I5. IfV desired/sample receiving' vessel v32 may be provided with volume calibrations so that to claim the invention broadly.

'I claim:

1. A sample receiving device adapted for removing samples from a fluid carrying conduit provided with a restriction comprising, in combination, a sample receiving chamber, a piston slidably arranged in said chamber, a valve casing, a second conduit arranged for uidly connecting the space dened by walls of the chamber and one end of the piston with said fluid carrying conduit on the downstream side of said restriction, a third conduit fluidly connecting a second space defined by walls of the chamber and the other end of said piston with said valvev casing, a fourth conduit adapted to fluidly connect said valve casing with said iiuid carrying conduit on the upstream side of said restriction, avfifth conduit adapted to fiuidly connect said valve casing with a sample receiving container, a valve member siidingly arranged in said casing to allow fiuid communication between said third and'fourth4 Vton and said valve member wherebysaid valve member is shifted from one position toranother by movement of said piston.

2. A device in accordance with claim 1 in which an elastic member is attached to said'valve member biassing it to said second position.

3. A device in accordance with claim l in which an elastic member is arranged in said valve casing to bias the valve member in said second position and a releasable catch is arranged adjacent said mechanical linkage to hold said valve member in said rst position and to be released by contact with said piston.

THOMAS V. MOORE.

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