US2760371A - Multiple venturi tube - Google Patents

Description

Aug. 28, 1956 w. E. BORDEN 2,7605371 MULTIPLEVENTURI TUBE Filed May 29, 1955 '2 Sheets-Sheet 1 INVENTOR. WALTER E. BORDEN ATTORNEYS 8, 1956 w. E. B'ORDEN 2,760,371

MULTIPLE VENTURI TUBE Fi l ed. May 9, 3' 2 Sheeis-Sheet 2 FIG. 6

INVENTOR. WALTER E. BORDEN ATTORN EYS MULTIPLE VENTURI TUBE Walter E. Borden, East Providence, R. 1., assignor to B-I-F Industries, Inc., a corporation of Rhode Island Application May 29, 1953, Serial No. 358,356

4 Claims. (Cl. 73-213) This invention relates to pressure diflerential creating devices which create a pressure differential that bears a definite relation to the rate of flow and more particularly to a pressure differential creating device of the venturi type.

The principle of the operation of the venturi tube is based upon conservation of energy wherein there is provided a pipe having a reduced section with no abrupt changes so that there will be no turbulence loses. It is well known that the velocity and kinetic energy are increased at the reduced section, the pressure in the reduced section being correspondingly decreased to reduce the potential energy and keep the total energy at the reduced section the same as the total energy in the pipe outside the reduced section. The gradual reduction in the area of the pipe such as in a venturi tube is necessary, for if the contraction takes place suddenly, turbulence and fluid resistance will occur with a corresponding energy loss without a corresponding increase in pressure. Ordinary venturi tubes must, therefore, of necessity have a relatively large structural length amounting to approximately ten times the diameter of the pipe and particularly in the case of pipe conduits of large diameter, it is necessary to place an extremely long venturi tube section therein in order to measure the flow.

It is therefore the main object of my invention to provide an improved pressure differential creating device of the venturi tube type which is relatively short in length and which may be easily installed in the pipe line.

A more specific object of my invention is to provide a multiple venturi tube type of construction with a plurality of venturi tubes of similar size and in which the corresponding cross sections of the various venturi tubes will be multiplied by the number of tubes in use to efiectively reproduce a venturi tube construction similar to a much larger and longer venturi tube.

With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings:

Figure 1 is a cross sectional View of the pressure difierential creating device of my invention in which four venturi tubes are being used;

Figure 2 is another sectional view taken on lines 22 of Figure 1;

Figure 3 is an end view of the pressure differential creating device of my invention;

Figure 4 is a sectional view taken on line 44 of Figure 1;

Figure 4a is a sectional view of a modified throat section of a venturi tube;

Figure 5 is a perspective view of one of the venturi type tubes utilized in my construction;

Figure 6 is a sectional view of the pressure differential creating device of my invention employing a modified form of venturi tube; and

Figure 7 is a perspective view of the modified form of venturi tube.

Referring now to the drawings, I provide a pressure differential device comprising a circular casing 10 having end flanges 11 and 12. A pressure tap 18 is provided through casing 10, and a separate pressure tap 20 extends through inlet flange 12. Within the casing 10 I provide a plurality of comparatively short venturi tube sections 14 of identical configuration and which, as shown in the embodiment in the drawings, have been arranged to substantially fill the interior area of the casing 10. Many arrangements of a plurality of venturi tube sections may be utilized, and the four in number, as shown in the drawings, are shown merely by way of example. Each of the venturi tube sections comprises a mouth portion 15, throat portion 16, and discharge portion 17 and is provided with strengthening ribs 19 which extend longitudinally on the exterior of their shell. Each of the venturi tubes 14 is supported in the cylindrical casing 10 by means of a mouth flange 21 and a discharge flange 22. Each of these plates is identical in construction, and, as shown in Figure 3, the discharge flange 22 embraces each of the discharge sections 17 of the venturi tube sections. Various means may be utilized to hold the plates 21, 22 and venturi sections 14 together, such as by establishing a press fit of the parts or by welding, brazing, or other known processes.

The end plates 22 entirely close oit the interior of the cylindrical section 10, except for the passage of fluid through the "venturi tube sections, and therefore to measure the pressure at the throat section 16 of the differential pressure measuring device, each of the venturi tube sections is provided with a slot or opening 23 which, as shown more particularly in Figures 4 and 5, extends circumferentially around the throat section 16 of the venturi tube sections between the ribs 19. If desired, a plurality of slots or openings may be provided around the throat section 16. For example, the venturi tube section of Figures 4 and 5 may be modified as shown in Figure 4a or alternatively the ribs 19 may be eliminated. It will thus be seen that the pressure connection 18 through the casing 10 communicates with the interior of the casing 10 and specifically to each of the throat sections 16 through the slots 23 in the venturi tube sections. In this manner an average pressure reading is obtained from each of the venturi tube sections, should, for any unforeseen reason, there be any variation in flow through the various venturi tube sections in spite of the fact that the venturi tube sections are each made identical to the other.

Referring now more particularly to Figures 6 and 7 in the drawings, there is shown a modification of a venturi tube section which may be inserted in the casing 10 as described above in connection with the previous embodiment. In Figures 6 and 7, the same reference numerals applied to Figures 1-5 are used to indicate like parts.

The venturi tube that is utilized in this embodiment comprises a mouth portion 15, throat portion 16', and discharge portion 17. Extending circumferentially around the throat section 16 is a groove or opening 23. An annular section 24 surrounds the groove or opening 23 and joins the two venturi tube portions 15 and 17' so as to form one continuous structure. A plurality of holes 25 are provided through the section 24 and connect the venturi tube throat section to the exterior, thus providing a pressure connection from the throat section 16. Each of the venturi tubes 14 is supported in the cylindrical casing 10 by means of a mouth flange 21 and discharge flange 22 in the same manner as the venturi tube section 14, as shown in the embodiment in Figures l-S. Since these end plates 22 and 23 entirely close ofi the interior of the cylindrical section 10, it will be seen that the pressure connection 18 through the casing communicates with each of the throat sections 16' of the venturi tubes 14 through the holes 25 in the annular section 24. Thus, in the same manner as the embodiment of Figure 1, an average pressure reading will be obtained from each of the venturi tube sections. However, if desired, only one of the venturi tube sections may be provided with pressure connections 25, inasmuch as each of the tubes is identical.

Assuming for the moment that the direction of the flow of the fluid to be metered will be from left to right as viewed on the drawing, it will be seen that this fluid will flow through a plurality of venturi shaped passageways and the same pressure result will be obtained as if the fluid were flowing through a single venturi shaped passage having a throat equal to the area of the combined throats of the several venturi shaped passages shown. The equivalent structure will therefore be a single venturi tube of a throat area and mouth area equal to the sum of the individual throat and mouth areas, respectively. Thus, the capacity of the multiple venturi tubes will be the same as a single venturi tube for the same size pipe, and the beta ratio (throat diameter to inlet or mouth diameter) will be identical. Should it be desired, the throat pressure could be measured merely by connecting with one of the throats of one of the venturi sections 14 although in the present embodiment it is preferred to make the connection as shown at 18 which connects through the various slots or openings 23 in the several venturi tube sections 14. The leading pressure connection, which is indicated at 20 as passing through the flange 12 of the differential creating device, may alternatively be taken directly out of the pipe line a suitable distance in advance of the pressure differential creating device.

With the arrangement just described it will be seen that I provide a pressure difierential creating device utilizing venturi type tubes, which is relatively short when considered with the diameter of the pipe into which it is to be inserted and yet the taper is gradual. This structure lends itself to be easily installed in a pipe line and is comparatively simple and capable of being manufactured at a low cost, and of utmost importance, it will give results with the same accuracy as a venturi tube of larger dimensions.

I claim:

1. A difierential pressure producing device for insertion in a conduit carrying flowing fluid comprising a casing with a bore therethrough, said bore being completely filled by a plurality of relatively small venturi type members having mouth, throat, and discharge portions, said members having their axes parallel to that of said bore and their mouths in a first plane normal to said bore, the throat portions of said members in a second plane normal to said bore, and the outlet portions in a third plane normal to said bore, the interstices in said first and third planes being filled with solid material to prevent flow of fluid through said casing except via said venturi members so that said casing has an area surrounding said throat portions, a high pressure connection in said casing upstream from said first plane, a low pressure connection in said casing between said first plane and said third plane to said area, and means at the throat of at least one of said venturi members allowing the pressure therein to be transferred to the interior of said casing.

2. A device as in claim 1 wherein each of the venturi type members is identical.

3. A device as in claim 1 wherein said venturi member has exterior longitudinal ribs and the last mentioned means consists of a plurality of circumferential slots between said ribs.

4. A device as in claim 1 wherein said venturi member has exterior longitudinal ribs and the last mentioned means consists of a continuous circumferential slot, said ribs bridging said slot.

References Cited in the file of this patent UNITED STATES PATENTS 772,279 Grouvelle et al Oct. 11, 1904 1,515,408 Puffer Nov. 11, 1924 1,648,708 Wilkinson Nov. 8, 1927 1,698,314 Mapeldsden Jan. 8, 1929 1,850,030 Pardoe Mar. 15, 1932 2,224,472 Chandler Dec. 10, 1940 2,337,921 Petroe Dec. 28, 1943 2,507,075 Wiegand et a1. May 9, 1950 FOREIGN PATENTS 879,212 France Nov. 10, 1942

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