US3783676A

US3783676A - Method and apparatus for measuring the density of a fluid

Info

Publication number: US3783676A
Application number: US00340929A
Authority: US
Inventors: J Tanney
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-03-13
Filing date: 1973-03-13
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08

Abstract

A fluid densitometer and its method of use, comprising directing a fluid jet into a fluid whose density is to be measured and towards an open end of a tube. The nozzle and tube have a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across the nozzle orifice, and the fluid pressure in the tube is measured to determine the density of the fluid into which the jet is directed. The geometry of the fluid jet is derived from

Description

United States Patent [191 Tanney 1 METHOD AND APPARATUS FOR MEASURING THE DENSITY OF A FLUID [76] Inventor: John W. Tanney, 34 l-Iarwick Crescent, Ottawa, Ontario, Canada 221 Filed: Mar. l3, 1973 211 Appl.N0.:340,9 29

[52] U.S. Cl. 73/32 Primary Examiner-Richard C. Queisser- Assistant Examiner-Stephen A. Kreitman Attorney-James R. Hughes Jan. 8, 1974 [57] ABSTRACT A fluid densitometer and its method of use, comprising directing a fluid jet into a fluid whose density is to be measured and towards an open end of a tube. The nozzle and tube have a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across the nozzle orifice, and the fluid pressure in the tube is measured to determine the density of the fluid into which the jet is directed. The geometry of the fluid jet is derived from R h p)/# R is the Reynolds number and is in excess of 1700, V is the velocity of the fluid delivered to the device, p is the density of the fluid delivered to the device, n is the viscosity of the fluid delivered to the device,

and h is the hydraulic radius obtained from,

h=(4A)/(P where A is the area of the fluid jet orifice,'and P is the distance around the perimeter of the fluid jet orifice.

8 Claims, 18 Drawing Figures JET f, Lj/f/ FLOIV AIR SUPPLY Il [1 l'ill PATENTEB 3.783.676

swan 1 OF 6 AIR 5 SUPPLY PATENTEUJAN 81974 3783676 SHEET 3 BF 6 PATENTED 81974 3.783.676

SHEET 5 0F 6 PowER SUPPLY I FLU l D [C REFERENCE DEN SITONETER UNIT PRESSURE MEASURING INDICATING 0R RECORDING DEvICE FEGIE.

PowER SUPPLY PRESSURE RATIO OR PREssURE DIFFERENCE 4/ CONTROLLER FLUIDIC REFERENCE DENSITOMETER UNlT PREssURE MEASURING INDICATING 0R RECORDING DEVICE FIGIT.

PATENTED JAN 81974 SHEET 5 OF 6 .1 METHOD AND APPARATUS FOR MEASURING THE DENSITY OF A FLUID This invention relates to a method and apparatus for measuring the density of a fluid.

Ideally a fluid densitometer should respond only to the density of the fluid to be measured, and should in other respects be substantially insensitive to its environment. Ruggedness is a very important feature for a fluid densitometer because the probability of damage during installation and use is reduced.

' It is an object of the invention to provide a fluid densitometer which is substantially insensitive to its environment, and which is rugged.

According to the present invention there is provided an apparatus for measuring the density of a fluid substance, comprising,

b. a pressurized fluid source connected to the device to deliver a fluid thereto at substantially constant pressure and cause a turbulent jetof fluid to issue from the orifice into the fluid substance.

c. a receiver means including a receiver mouth facing the orifice to be pressurized by the dynamicpressure of the jet therefrom, and fluid substance entrained therein, within the area bounded by the receiver mouth.

d. mounting means connecting the receiver means and the device with a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across theorifice,

e. indicating means connected to the receiver means for indicating, in terms of the fluid pressure therein the density of the fluid substance,

f. and wherein the geometry of the fluid jet orifice is derived from, Y

R is the Reynolds number and is in excess of I700,

V is the velocity of the fluid deliveredto the device,

p is the density of the fluid delivered to the device,

t is the viscosity of the fluid delivered to the device,

and

h is the hydraulic radius obtained from, h=(4A)/P, where A is the area of the fluid jet orifice, and

P is the distance around the perimeter of the fluid jet orifice.

Further according to the present invention there is provided a method of measuring the density of a fluid substance comprising,-

, a. mounting a nozzle device and a receiver means in the fluid substance with a receiver mount of the receiver means facing an orifice of the device for the receiver mouth to be pressurized by the dynamic pressure of a jet therefrom and with a turbulent jet forming space extending between the orifice and the receiver mouth of less than fifty times the maximum distance across the orifice,

b. delivering a fluid at substantially constant pressure to the device to cause a turbulent jet to issue from the orifice into the fluid substance and pressurize the receiver means by means of the dynamic pressure in' the turbulent jet and fluid substance entrained therein, and

c. determining, in terms of the fluid pressure within the receiver, the density of the fluid substance,

d. and wherein the geometry of the fluid jet orifice is derived from R (V h p)/;.:., where R is the Reynolds number and is in excess of 1700,

V is the velocity of the fluid delivered to the second device,

p is the density of the fluid delivered to the second device,

p. is the viscosity of the fluid delivered to the device,

and

h is the hydraulic radius obtained from, h=(4A)/P A is the area of the fluid jet orifice, and

P is the distance around the perimeter of the fluid jet orifice of the second device.

In the accompanying drawings which illustrate, by way of example, embodiments of the invention,

FIG. 1 is a diagrammatic sectional side view of an apparatus for measuring the density of a fluid substance,

FIG. 2 is a graph of the fluid pressure in the receiver mouth, of the apparatus shown in FIG. 1, plotted against the density of the surrounding fluid, with the nozzle and receiver spaced at five times the nozzle orifice diameter, V

FIG. 3 is a graph of the fluid pressure in the receiver mouth of the apparatus shown in FIG. 1, plotted against the density of the surrounding fluid, with the nozzle and receiver spaced at various distances,

FIG. 4 is a sectional side view of the nozzle and tube shown in FIG. 1, adapted to measure the density of a stream of a fluid substance,

FIG. 5, is a sectional end view along VV, FIG. 4,

FIG. 6 is a similar sectional end view to that shown in FIG. 5, but of a different apparatus,

7 FIG. 7 is a similar view to that shown in FIG. 4 but of another different apparatus,

FIG. 8 is a similar view to that shown in FIG. 4 but of a further different apparatus,

. FIG. 9 is asimilar view to that shown in FIG. 4 but of another different apparatus,

FIG. 10 is a similar view to that shown in FIG. 4 but of a further different apparatus,

FIG. 11 is a plan view of an apparatus, for measuring the density of a fluid, mounted in a wall member,

FIG. 12 is a side view of the apparatus shown in FIG. 11,

FIG. 13 is a sectional side view of a fluid jet forming device and a receivermeans, both mounted in a casing, and for use as a comparator with the apparatus described with reference to FIGS. 1 through 10,

FIG. 14 is a similar view to FIG. 13, but of a different comparator,

FIG. 15 is another similar view to FIG. 13, but of another comparator,

FIG. 16 is a flow diagram of the apparatus shown in any of FIGS. 13 through 15 coupled to the apparatus shown and described with reference to any of FIGS. 1 through 10,

FIG. 17 is a different flow diagram to that shown in FIG. 14, and

FIG. 18 is a an adjustable apparatus for measuring the density of a fluid substance.

In FIG. 1 there is shown a fluid jet forming device, in theform of a nozzle 1, having a fluid jet orifice, a pressurized fluid source, in the form of an air supply 3, connected to the nozzle 1 to deliver a fluid thereto at substantially constant pressure and cause a turbulent jet of fluid to issue from the orifice into the fluid substance. A receiver means inthe form of a tube 2, includes a receiver mouth facing the orifice to be pressurized by the dynamic pressure of the jet therefrom, and fluid substance entrained therein, within the area bounded by the receiver mouth. The tube 2 and nozzle 1 are mounted with a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across the orifice. Indicating means, in the form of a manometer 4, is connected to the tube 2 for indicating in terms of the fluid pressure therein the density of the fluid substance.

The geometry of the fluid jet orifice is defined as its hydraulic radius h being such as to produce a turbulent jet on the basis of the velocity V of the supply fluid from the pressurized fluid source at the outlet of said orifice, the density p of such supply fluid, the viscosity p. of such supply fluid, and the hydraulic radius h combining, with consistent dimensions to produce a dimensionless Reynolds number R is excess of 1700 from the relationship where the hydraulic radius h is defined in terms of the area A of the fluid jet orifice in the place of the outlet of said orifice and the perimeter P of said orifice in said plane by the relationship h=(4A)/P The velocity V of said supply fluid at the outlet of said orifice may be determined experimentally or derived by those skilled in the art from published texts.

In this specification "turbulent jet forming space is defined as a space in which the turbulent jet is allowed to expand in a manner similar to the expansion ofa turbulent jet in a volume which is unbounded at least to one side.

In operation the apparatus is arranged as shown in FIG. I, with the nozzle 1 and receiver 2 mounted in the fluid substance whose density is to be measured, in this instance a gas. The apparatus was arranged with the distance x five times the minimum distance across the fluid jet orifice of the nozzle 1, which in this case was the diameter d". A turbulent jet of air was directed from the nozzle towards the tube 2.

The turbulent jet is defined in relation to FIG. 1 as being approximately conical in form when produced by a circular jet forming orifice and having a virtual origin on its axis approximately five diameters upstream of the plane of exit and the flow from the jet forming device and is clearly distinguished from what is known as laminar flow, in which the streamlines are essentially parallel, as described by Mott in US. Pat. No. 3,429,323, dated Feb. 25, 1969.

With the apparatus operating in the above manner, the pressure P given by the manometer 4 will depend upon the density of the fluid substance surrounding the apparatus and thus the density of this fluid substance may be determined from this measurement.

One reason for the pressure P varying with the surrounding fluid density may be the variation of the spreading rate of the substantially unbounded turbulent jet with variations in the density of the fluid in which it is submerged. With a given momentum at the jet orifice, the momentum at the receiver mouth is primarily dependent on the spreading rate of such turbulent jet. This phenomenon may be further complicated by the effect of concentration of supply fluid and surrounding fluid at the receiver mouth. These effects are also dependent on jet orifice to receiver mouth spacing and to some extent on supply pressure.

Tests were carried out to determine the sensitivity of the apparatus when used to measure various gas densities by supplying the nozzle 1 with air at various fixed pressures from the supply 3 and with various spacings between the jet orifice 1 and the receiver mouth 2. In these tests the manometer 4 was capable of giving a maximum reading of eighty inches of mercury.

The results of the tests are shown in the graphs of FIG. 2, where the horizontal ordinate is the density of the surrounding gas in lbs/cu. ft., and the vertical ordinate is the pressure P in inches of Mercury. The air supply pressure from the air supply 3 for readings 5 was 15 inches of mercury, for readings 6 was 30 inches of mercury, for readings 7 was 45 inches of mercury, for readings 8 was 60 inches of mercury, and for readings 9 was inches of mercury. The readings designated thus 0 were for measuring the density of helium as a surrounding gas, and thus [:I for measuring the density of air as the surrounding gas and thus A for measuring the density of monochlorodifluoromethane as the surrounding gas.

The results of these tests indicate that, with the apparatus used, an air supply pressure of the order of 60 inches mercury from the air supply 3 was the optimum value for a nozzle 1, to tube 2 spacing x of five diameters. The reason for this is that with an air supply pressure of the order of 60 inches of mercury the maximum change in pressure p" in the tube 2 is obtained for a given range of densities of gas surrounding the apparatus, and so the sensitivity of the apparatus is greatest.

With the air supply pressure maintained at 60 inches of mercury the tests were continued using the same gases, but with the distance x between the nozzle 1 and the tube 2 set at different dimensions.

The results of these tests are shown in FIG. 3, where the pressure P is plotted against the density of the surrounding gas, in the same manner as in FIG. 2. In FIG. 3 the readings obtained were 10 with x" l0.35d, 11 with x 7.15. d, 14 with x 6.08. d, 15 with x 5.00.d, and 16 with "x 3.93. d". It will be noted that the readings 15 included 0 for argon, A for carbon dioxide, and 1 for dichlorodifluoromethane.

From the results shown in FIG. 3, it can be seen that with the apparatus used a nozzle 1 to tube 2 spacing x of between eight of ten times d, the nozzle diameter, provides the maximum sensitivity at 60 inches of mercury, air supply pressure. However, depending upon the apparatus used the spacing x may be up to 30 or even 50 times d and give useful results.

Using the apparatus as described a nozzle 1 to tube 2 spacing x of 8.22.d, the sensitivity of the apparatus is approximately 50 in/Hg/lb/cu. ft. at a gas density of the surrounding gas of 0.10 lbs/cu.ft., 10 in .Hg/lb/cu.ft., at a gas density 0.50 lb/cu.ft, and 5 in Hg/lb/cu. ft., at a gas density of l lb/cu.ft.

FIGS. 4 and 5 shows a similar apparatus to that shown in FIG. 1, and indentical parts shown therein are referred to by the same reference numerals, and the previous description is relied upon to describe them.

In FIGS. 4 and 5 the apparatus shown in FIG. 1 is adapted for measuring the density of a fluid substance when the apparatus is disposed within a stream of the fluid substance. In order that the measurements of the apparatus will not be changed by the flow of the fluid v substance, and particularlya flowtransverse to the tur- .bulentjet, the nozzle 1 and receiver tube 2 are disposed within a cylindricalhousing l8 enclosing the turbulent jet forming space, to allow substantially free interaction and mixing of the fluid surrounding such apparatus with the turbulent jet and not cause entrainment or attachment of the turbulent jet to the housing. The cylindrical housing 18 is shown attached to the tube 2 by a support 19. It will be appreciated that the cylindrical housing 18 could be similarly attached to the nozzle 1 and for rigidity could be similarly attached to both noz-v zle l and the receiver tube 2 to form a means of mounting and spacing said components.

In FIG. 6 where similar parts to those shown in FIGS. 4 and 5 are referred to by the same reference nurnerals and the previous description is relied upon to describe them, the cylindrical housing 18 is secured to the tube 2 by two

supports

20 and 21 to secure the easing 18 to the tube 2 in a sturdy manner. The cylindrical casing 18 may be secured in this manner to nozzle 1 in the same manner.

If desired any number of

supports

20 and 21 may be used to secure the casing 18 in position-provided they do not obstruct the mixing of the fluid surrounding such apparatus, including the casing 18, with the turbulent jet.

In FIG. 7 where 'similarparts to those shown in FIG. 1 are referred to by the same reference numeral, the nozzle 1 and tube 2 are disposed within a fluid-permeable casing in the form of a mesh'casing 21. The casing 21 is shown supported bya mesh 22a at one end.

If desired the casing 21 may be supported on the tube 2 by a further mesh (not shown) at the other end of the casing 21. In other embodiments the casing 21' is supported in the nozzle 1 and/or tube 2 by the-supports similar to those shown in FIG. 6. I

The casing 21 serves a similar purpose to the casing 18 in FIG. 4, but greater access for fluid to the space between the nozzle 1 and the tube 2. The casing 21, when closed at'one or both ends by mesh, also obstructs the passage of any particles, whose size approaches the internal cross-sectional dimension of the tube 2, to the tube 2from the fluid whose density is being measured. In other words the casing 21 obstructs the passage of particles to the tube 2 which would block the tube 2. The casing is particularly useful when the fluid whose density is measured contains solid particles as will be described later.

In FIG. 8 there is shown a nozzle 2 and a receiver tube 23 both of which function in a similar manner to the nozzle 1 and tube 2 shown in FIG. 1. The nozzle 22 and tube 23 are disposed between two inwardly curved supporting

plates

24 and 25 which allow free interaction and mixing of the surrounding fluid with the jet on opposite sides of the jet. The

plates

24 and 25 extend beyond the nozzle 22 and tube 23, and are joined to one another by the nozzle 22 and the tube 23. The

curved plates

24 and 25 provide better mechanical protection for the nozzle 22 and the tube 23 than plane plates, but in other embodiments one or both of the

plates

24 and 25 may be plane, furthermore only one of the components selected from the group comprising the nozzle 22 or the tube 23 may be mounted between the

plates

24 and 25. In different embodiments the

plates

24 and 25 may be curved in a transverse direction to the jet from the nozzle 22 or one or both of the

plates

24 and 25 may have a double curvature.

In FIG. 9 parts similar to those shown in FIG. 8 are designated by thesame reference numerals and the previous-description is relied upon to describe them. The nozzle 22 and tube 23 are disposed between two outwardly curved plates 24a and 25a which allow free interaction and mixing of the surrounding fluid with the jet on opposite sides of the jet. The plates 24a and 25a extend beyond the nozzle 22 and receiver tube 23 and are joined to one another by either or both the nozzle and tube 23. As in the embodiment described with reference to FIG. 8 the curved plates 24a and 25a provide better mechanical protection for the nozzle 22 and .tube 23 than plane plates, but in other embodiments the one or both of the plates 24a and 250 may be curved in another axis or have double curvature or may be plane, furthermore only one of the components selected from the group comprising the nozzle 22 and tube 23 may be mounted between the plates 24a and 25a.

In FIG. 10 parts similar to those shown in FIG. 8 are designated by the same reference numerals and the previous description is relied upon'to describe them. The nozzle and tube 23 are disposed between two plates 24b and 25b which are curved in the same direction and which allow free interaction and mixing of the surrounding fluid with the jet on opposite sides of the jet. The plates 24b and 25b extend beyond the nozzle 22 and tube 23 and may be joined to one another by either or both the nozzle 22 and tube 23. The curved plates 24b and 25b provide better mechanical protection for the nozzle 22 and tube 23 than plane plates. In

other embodiments the plates 24b and 2511 may be' curved transversely to the jet and one or both of the plates may have double curvature or may be plane. In other embodiments only one of the components selected from the group comprising the nozzle 22 and tube 23 is mounted between plates 24b and 25b.

It will be appreciated that the nozzle and tube of any of the previous embodiments need not have passages or circular cross-section, however, the particular shape may affect the characteristics of the apparatus and the manometer may have to be graduated in terms of the density of the gas to be measured to suit these characteristics.

In FIGS. 11 and 12 a nozzle and receiver tube 27 are shown mounted in a curved plate 28 which may (from a portion of a fluid passage (not shown))' be attached to or built into a surface bounding the fluid whose density is to be measured. With this apparatus the characteristics of the apparatus will also have to be taken into account but this apparatus illustrates how the invention may be incorporated into the duct or wall of a fluid containing member. The nozzle 26 and' tube 27 are shown having orifices of the nozzle 26 and tube 27 may also be disposed from the plate 28 and this may be desirable when the plate 28 (forms a portion of) is attached to or built into the wall of a fluid passage because these orifices may then be disposed in the passage at a position beyond the fluid bondary layer or area of reduced fluid velocity near the wall bounding the passage. The curved plate 28 may also be curved in a direction transverse to the jet or have a double curvature or be plane if desired.

In FIG. 13 there is shown a comparator which provides an output pressure which is proportional to the momentum in the contained jet. The momentum in the jet being a function of both density of the supply fluid and the difference between the supply pressure to the jet orifice and the pressure of the fluid surrounding the comparator. The output of the comparator is proportional to the output of any of the apparatus described with reference to FIGS. 1 to 12 when such apparatus is surrounded by a fluid whose density is the same as the fluid supplied to the nozzle of such apparatus and said comparator and the pressure of the fluid supplied to and surrounding such apparatus and such comparator is the same.

The comparator shown in FIG. 13 comprises a second fluid jet forming device in the form of a nozzle 29 having a fluid jet orifice, a receiver tube 30 forming a second receiver means and a casing 31 closed at one end 32 and enclosing a turbulent jet forming space, this is a space that allows the turbulent jet from the nozzle to expand in a manner similar to the expansion ofa turbulent jet in a volume which is substantially unbounded at least to one side and which is filled with the same fluid that forms the jet. Such comparator casing also restricts any interaction between the jet enclosed by the jet enclosed by the

comparator casing

31 and 32 and the fluid surrounding such casing except for the effect of the pressure of the surrounding fluid on the flow out of the comparator casing through any openings that are provided for such flow out of the casing and excluding the openings which constitute the nozzle and receiver.

The turbulent jet forming space extending between the nozzle 29 and tube 30 extends a distance of less than 50 times the maximum distance across the orifice of the nozzle 29.

The geometry of the fluid jet orifice of the nozzle 29 is derived from a R is the Reynolds number and is in excess of 1700,

V is the velocity of the fluid delivered to the second device,

p is the density of the fluid delivered to the second device,

p. is the viscosity of the fluid delivered to the device,

and

It is the hydraulic radius obtained from, Ql h where A is the area of the fluid jet orifice, and

By comparing the pressure in the tube 30 with the pressure in the receiver tubes shown and described in embodiments illustrated in FIGS. 1 to 13 variations in the pressure and density of the supply fluid and the pressure of the fluids surrounding both the comparator and the previous embodiments may be taken into account. The comparator may be disposed in the same fluid substance as the fluid density measuring apparatus with which it is to be used as a reference. Alternately it may be disposed in another fluid substance which may be isolated or in contact with the fluid substance whose density is to be measured.

A further function of the comparator is the provisions of a bias pressure, proportional to the difference between the supply pressure and the pressure of the fluid surrounding such comparator, which is used to partially balance the output of any of the density measuring apparatus. described with reference to FIGS. 1 to 12. The partial balancing of the output from the density measuring apparatus, as described with reference to FIGS. 1 to 12 against the output from the comparator reduces the range of differential pressure measurement required for the outputs of such a combination of apparatus and thereby provides increased sensitivity.

The comparator may take a number of forms such as that shown in FIG. 14 where the tube 30 is mounted in an end wall 33 at the end of the casing opposite to the nozzle 29 and holes are provided in the casing 31 for fluid outlets.

The comparator shown in FIG. 15 has a nozzle 35 and a tube 36 mounted in a casing 37 provided with a fluid outlet 38.

In FIG. 16 there is shown a fluid supply 39, an apparatus for measuring a fluid density 40, a comparator 41, and a fluid pressure measuring, indicating, or recording device 42. The fluid supply 39 may be a pump, compressor, gas bottle or any other source of fluid under pressure, and a pressure regulator. Preferably a filter (not shown) is used to filter the fluid from the supply 39. The apparatus 40 may be any one of the types described with reference to FIGS. 1 to 12 and the comparator 41 may be any of the types described with reference to FIGS. 13 to 15. The nozzles of the apparatus 40 and the comparator 41 are connected to the supply 39. The tubes of the apparatus 40 and the comparator 41 are connected to the device 42, which may be a pressure gauge, manometer, recorder, transducer, pressure transmitter, or any other device which can accept a fluid pressure and produce from it a useful output.

In operation the apparatus is arranged as shown in FIG. 16 with the density measuring apparatus of fluidic densitometer 40 and the comparator or reference unit 41 disposed in the fluid whose density is to be measured. The fluid supply or power supply supplies fluid under equal pressure to the nozzles of the apparatus 40 and the comparator 41. The fluid pressures in the tubes of the apparatus 40 and the comparator 41 are indicated or recorded by the device 42 from which the density of the fluid to be measured is deduced, if desired as a direct reading.

Where the pressure of the fluid, whose density is to be measured, is likely to change it may be desirable from the volume or the pressure of the fluid supply to the nozzles of the density measuring apparatus of FIG. 16 to be adjusted accordingly.

In FIG. 17 there is shown an apparatus comprising a fluid supply 44, a-pressure ratio or pressure difference controller 46, a fluid density measuring apparatus 47, a comparator 48, and a pressure measuring, indicating or recording device 49.

The apparatus is arranged as shown with the apparatus 47 and comparator 48 disposed within a fluid 50 whose density is to be measured. This apparatus operates in the same manner as the apparatus shown in FIG. 14 except that the controller maintains a constant difference or a constant absolute pressure ratio between the pressure of the fluid supplied to the nozzles of the apparatus 47 and the comparator 48 and the pressure of the fluid 50. Whether the controller maintains a constant difference or a constant absolute pressure ratio will depend upon the characteristics required.

In FIG. 18 there is shown a nozzle 51 and tube 52. The nozzle 51 has a threaded exterior 53 with a portion 54 of the nozzle exterior recessed beneath the thread and graduated. The nozzle 51 has a keyway 55 and is screwed into a micrometer drum 56. The micrometer drum 56 is rotatably mounted in a support 57 and held therein by a collar 58 on the nozzle 51. The support has a key 59 to slidably support the nozzle 51 but prevent rotation thereof. The rear end of the nozzle' 51 is connected by a flexible tube 60 to a source of pressurized fluid. The tube 52 is held in a fixed position by a support 61.

it will be appreciated that the adjustment, as illustrated in FIG. 18, may beapplied to the receiver tube rather than the nozzle and further that the nozzle or receiver tube may be allowed to rotate with adjustment provided a rotary joint is provided between the nozzle, or receiver tube, 51 and the connecting tube 60.

In operation the nozzle 51 and tube function in the same manner as the previous embodiments. This embodiment facilitates adjusting the distance x between the nozzle 51 and the tube 52 by rotating the micrometer drum 56 to the desired setting. Thus the apparatus can be adjusted to compensate for manufacturing inaccuracies in the nozzle or tube or for flow restrictions in the means for connecting the pressurized source to the nozzle. Further the apparatus can be adjusted to suit any change in the working conditions of the apparatus.

The use of the adjustment means, describedwith reference to FIG. 18, with any of the embodimentsdescribed with reference to FIGS. 1 to 12 allows the sensitivity of such embodiments to be arranged to meet specific requirements'by adjusting the nozzle orifice to receiver spacing as illustrated by the comparison of such spacing versus sensitivity shown in FIG. 3.

The use of a comparator allows the adjustment 'with reference to FIG. 18, to be used to adjust such apparatus tohave an output equal to the comparator under specific conditions such as equal density and pressure of the surrounding fluid. Similarly a fixed geometry densitymeasuring apparatus can be balanced in output under specificconditions by the use of the adjustment described with reference to FIG. 18 applied to the comparator.

The use of the adjustment, described with reference to H6. 18, with both the density measuring apparatus and the comparator allows the adjustmentof both the sensitivity of the density measuring apparatus and the corresponding bias output of the comparator under specific conditions.

It will be appreciated thatany of FIGS. 1 to 18 may be used to measure the density of a stationary fluid or a fluid flowing in any direction relative to the nozzle and tube.

This present invention need not involve pumping, compressing or controlling of the flow of fluid density is measured, nor does it involve the interaction of moving mechanical components with the measured fluid. The present invention can therefore be used to measure the density of high temperature, corrosive or explosive fluids and-mixtures of fluids and solids. This requires only a fixed geometry and a knowledge of the supply pressure and supply fluid density to obtain an output pressure'which is a known function of surround ing or measured fluid density.

1 claim:

1. Apparatus for measuring the density of a fluid substance comprising a. a fluid jet forming device having a fluid jet orifice,

pressure and cause a turbulent jet of fluid to issue from the orifice into the fluid substance,

c. a receiver means including a receiver mouth facing the orifice to be pressurized by the dynamic pressure of the jet therefrom, and fluid substance entrained therein, within the area bounded by the receiver mouth,

d. mounting means connecting the receiver means and the device with a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across the orifice,

e. means connected to said receiver means for measuring the fluid pressure therein, for providing an indication of the density of the fluid substance,

f. and wherein the geometry of the fluid jet orifice is derived from R (V hp)/u, where Y R is the Reynolds number and is in excess of 1700,

V is the velocity of the fluid delivered to the device, p is the density of the fluid delivered to the device, p. is the viscosity of the fluid delivered to the device,

and

h is the hydraulic radius obtained from, h=4 A/P A is the area of the fluid jet orifice, and

P, is the distance around the perimeter of the fluid jet 2. Apparatus according to claim I, further comprising a cylindrical casing which is permeable to the fluid substance at both ends and encloses the turbulent jet forming space, and the mounting means mounts the device and the receiver means coaxially within the casing.

3. Apparatus according to claim 2, wherein the easing is permeable to the fluid substance, the mounting means includes an end closure atone end of the casing, and the end closure is permeable to the fluid substance.

4. Apparatus for measuring the density of a fluid substance comprising, a first fluid jet forming device having a fluid jet orifice, a pressurized fluid source connected to the firstdevice to deliver a fluid thereto at substantially constant pressure and cause a turbulent jet of fluid to issue from the orifice into the fluid substance, a first receiver means including a receiver mouth, facing the first orifice, to be pressurized by the dynamic pressure of the jet therefrom, and fluid substance entrained therein, within the area bounded by the receiver mouth, mounting means connecting the first receiver means and the first device with a turbulent jet forming space extending between them a distance of less than 50 times the maximum distance across the first orifice the first fluid jet forming device and the first receiver means are for disposition in a position of the fluid substance, and which includes a comparator comprising a second fluid jet forming device having a fluid jet orifice, a pressurized fluid source connected to the second device to deliver a fluid thereto at substantially constant pressure and cause a second turbulent jet of fluid to issue from the second orifice into and entrain fluid having substantially the same density as the fluid substance, a second receiver means including a receiver mouth facing the orifice of the second device to be pressurized by the dynamic pressure b. a pressurized fluid source connected to the device to deliver a fluid thereto at substantially constant of the jet therefrom, and fluid entrained therein, within the area bounded by the receiver mouth, and a casing having an outlet for fluid from the second jet and connecting the second receiver means and the second destance, and wherein the geometry of the first and secnd orifices is derived from R is the Reynolds number and is in excess of 1700,

V is the velocity of the fluid delivered to the device whose orifice geometry is being derived,

p is the density of the fluid delivered to that device,

p. is the viscosity of the fluid delivered to that device,

h is the hydraulic radius obtained from, h (4A)/P where v AM-m '7 mwfl mm-- A is the area of that fluid jet orifice, and

P, is the distance around the perimeter of that fluid jet orifice.

5. Apparatus according to claim '4, further comprising a pressure controller responsive to changes in the pressure of the fluid substance for adjusting the supply pressure of fluid to the first and second orifices in response to changes in the pressure of the fluid substance.

6. A method of measuring the density of a fluid substance comprising a. mounting a nozzle device and a receiver means in the fluid substance with a receiver mouth of the receiver means facing an orifice of the device for the receiver mouth to be pressurized by the dynamic pressure of a jet therefrom and with a turbulent jet forming space extending between the orifice and the receiver mouth ofless than fifty times the maximum distance across the orifice,

b. delivering a fluid at substantially constant pressure to the device to cause a turbulent jet to issue from the orifice into the fluid substance and pressurize the receiver means by means of the dynamic pressure in the turbulent jet and fluid substance entrained therein, and

c. measuring the fluid pressure within the receiver as a basis for determining the density of the fluid substance,

d. and wherein the geometry of the fluid jet orifice is derived from R is the Reynolds number and is in excess of 1700,

V is the velocity of the fluid delivered to the device,

p is the density of the fluid delivered to the device,

u is the viscosity of the fluid delivered to the device,

and

is. t llr ulisrsd us ebtail simmrhimtll fi A is the area of the fluid jet orifice, and

P, is the distance around the perimeter of the fluid jet orifice of the device.

7. A method according to claim 6, comprising placing around the turbulent jet forming space, a cylindrical casing permeable at both ends, to substantially present changes in the fluid pressure within the receiver by flow of the fluid substance.

8. A method of measuring the density of a fluid substance comprising, mounting a first nozzle device and a first receiver means in the fluid substance, with a receiver mouth of the first receiver means facing an orifice of the first device for the first receiver mouth to be pressurized by the dynamic pressure of a jet therefrom. and with a turbulent jet forming space extending between the first orifice and the first receiver mouth less than fifty times the maximum distance across the first orifice, delivering a fluid at substantially constant pressure to the first device to cause a turbulent jet to issue from the orifice into the fluid substance and pressurize the first receiver means by means of the dynamic pressure in the turbulent jet and fluid substance entrained therein, mounting a comparator in fluid having substantially the same density as the fluid substance in which the first nozzle and first receiver are mounted, the comparator comprising a second nozzle device and second receiver means, with a receiver mouth of the receiver means facing the orifice of the second device to be pressurized by the dynamic pressure of a jet therefrom and fluid entrained therein, with the area bounded by the receiver mouth, and a casing having an outlet for fluid from the second device and connecting the second receiver means and the second device with a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across the orifice of the second device, delivering a fluid at substantially constant pressure to the second device to cause a second turbulent jet to issue from the orifice into and entrain the fluid and pressurize the receiver means by means of the dynamic pressure in the second turbulent jet and entrained fluid, and measuring the differential fluid pressure between the pressures in the first and second receivers as a basis for determining the density of the fluid substance, and wherein the geometry of the orifices of the first and second devices are derived from

Claims

1. Apparatus for measuring the density of a fluid substance comprising a. a fluid jet forming device having a fluid jet orifice, b. a pressurized fluid source connected to the device to deliver a fluid thereto at substantially constant pressure and cause a turbulent jet of fluid to issue from the orifice into the fluid substance, c. a receiver means including a receiver mouth facing the orifice to be pressurized by the dynamic pressure of the jet therefrom, and fluid substance entrained therein, within the area bounded by the receiver mouth, d. mounting means connecting the receiver means and the device with a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across the orifice, e. means connected to said receiver means for measuring the fluid pressure therein, for providing an indication of the density of the fluid substance, f. and wherein the geometry of the fluid jet orifice is derived from R (V h Rho )/ Mu , where R is the Reynolds number and is in excess of 1700, V is the velocity of the fluid delivered to the device, Rho is the density of the fluid delivered to the device, Mu is the viscosity of the fluid delivered to the device, and h is the hydraulic radius obtained from, h 4 A/P1, where A is the area of the fluid jet orifice, and P1 is the distance around the perimeter of the fluid jet orifice.

2. Apparatus according to claim 1, further comprising a cylindrical casing which is permeable to the fluid substance at both ends and encloses the turbulent jet forming space, and the mounting means mounts the device and the receiver means coaxially within the casing.

3. Apparatus according to claim 2, wherein the casing is permeable to the fluid substance, the mounting means includes an end closure at one end of the casing, and the end closure is permeable to the fluid substance.

4. Apparatus for measuring the density of a fluid substance comprising, a first fluid jet forming device having a fluid jet orifice, a pressurized fluid source connected to the first device to deliver a fluid thereto at substantially constant pressure and cause a turbulent jet of fluid to issue from the orifice into the fluid substance, a first receiver means including a receiver mouth, facing the first orifice, to be pressurized by the dynamic pressure of the jet therefrom, and fluid substance entrained therein, within the area bounded by the receiver mouth, mounting means connecting the first receiver means and the first device with a turbulent jet forming space extending between them a distance of less than 50 times the maximum distance across the first orifice , the first fluid jet forming device and the first receiver means are for disposition in a position of the fluid substance, and which includes a comparator comprising a second fluid jet forming device having a fluid jet orifice, a pressurized fluid source connected to the second device to deliver a fluid thereto at substantially constant pressure and cause a second turbulent jet of fluid to issue from the second orifice into and entrain fluid having substantially the same density as the fluid substance, a second receiver means including a receiver mouth facing the orifice of the second device to be pressurized by the dynamic pressure of the jet therefrom, and fluid entrained therein, within the area bounded by the receiver mouth, and a casing having an outlet for fluid from the second jet and connecting the second receiver means and the second device with a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across the second orifice, and means connected to the first and second receiver means for measuring the differential pressure therebetween for providing an indication of the density of the fluid substance, and wherein the geometry of the first and second orifices is derived from R (V h Rho )/ Mu R is the Reynolds number and is in excess of 1700, V is the velocity of the fluid delivered to the device whose orifice geometry is being derived, Rho is the density of the fluid delivered to that device, Mu is the viscosity of the fluid delivered to that device, h is the hydraulic radius obtained from, h (4 A)/P1, where A is the area of that fluid jet orifice, and P1 is the distance around the perimeter of that fluid jet orifice.

5. Apparatus according to claim 4, further comprising a pressure controller responsive to changes in the pressure of the fluid substance for adjusting the supply pressure of fluid to the first and second orifices in response to changes in the pressure of the fluid substance.

6. A method of measuring the density of a fluid substance comprising a. mounting a nozzle device and a receiver means in the fluid substance with a receiver mouth of the receiver means facing an orifice of the device for the receiver mouth to be pressurized by the dynamic pressure of a jet therefrom and with a turbulent jet forming space extending between the orifice and the receiver mouth of less than fifty times the maximum distance across the orifice, b. delivering a fluid at substantially constant pressure to the device to cause a turbulent jet to issue from the orifice into the fluid substance and pressurize the receiver means by means of the dynamic pressure in the turbulent jet and fluid substance entrained therein, and c. measuring the fluid pressure within the receiver as a basis for determining the density of the fluid substance, d. and wherein the geometry of the fluid jet orifice is derived from R (V h Rho )/ Mu R is the Reynolds number and is in excess of 1700, V is the velocity of the fluid delivered to the device, Rho is the density of the fluid delivered to the device, Mu is the viscosity of the fluid delivered to the device, and h is the hydraulic radius obtained from, h (4 A)/P1 A is the area of the fluid jet orifice, and P1 is the distance around the perimeter of the fluid jet orifice of the device.

8. A method of measuring the density of a fluid substance comprising, mounting a first nozzle device and a first receiver means in the fluid substance, with a receiver mouth of the first receiver means facing an orifice of the first device for the first receiver mouth to be pressurized by the dynamic pressure of a jet therefrom, and with a turbulent jet forming space extending between the first orifice and the first receiver mouth less than fifty times the maximum distance across the first orifice, delivering a fluid at substantially constant pressure to the first device to cause a turbulent jet to issue from the orifice into the fluid substance and pressurize the first receiver means by means of the dynamic pressure in the turbulent jet and fluid substance entrained therein, mounting a comparator in fluid having substantially the same density as the fluid substance in which the first nozzle and first receiver are mounted, the comparator comprising a second nozzle device and second receiver means, with a receiver mouth of the receiver means facing the orifice of the second device to be pressurized by the dynamic pressure of a jet therefrom and fluid entrained therein, with the area bounded by the receiver mouth, and a casing having an outlet for fluid from the second device and connecting the second receiver means and the second device with a turbulent jet forming space extending between them a distance of less than fifty times the maximum distance across the orifice of the second device, deLivering a fluid at substantially constant pressure to the second device to cause a second turbulent jet to issue from the orifice into and entrain the fluid and pressurize the receiver means by means of the dynamic pressure in the second turbulent jet and entrained fluid, and measuring the differential fluid pressure between the pressures in the first and second receivers as a basis for determining the density of the fluid substance, and wherein the geometry of the orifices of the first and second devices are derived from R (V h)/ Mu R is the Reynolds number and is in excess of 1700, V is the velocity of the fluid delivered to the device whose orifice geometry is being derived, Rho is the density of the fluid delivered to that device, Mu is the viscosity of the fluid delivered to that device, and h is the hydraulic radius obtained from, h (4A)/P1, where A is the area of that fluid jet orifice, and P1 is the distance around the perimeter of that fluid jet orifice.