US3861198A

US3861198A - Fluid analyzer with self-cleaning viewing windows

Info

Publication number: US3861198A
Authority: US
Inventors: James J Shea
Original assignee: Gam Rad Inc
Current assignee: Gam Rad Inc
Priority date: 1972-11-03
Filing date: 1972-11-03
Publication date: 1975-01-21
Anticipated expiration: 1992-01-21

Abstract

A turbidimeter or fluid analyzer having the light transmitting windows maintained clean by apparatus directing a flow of fluid thereupon.

Description

United States Patent Shea [ FLUID ANALYZER WITH SELF-CLEANING VIEWING WINDOWS [75] Inventor: James J. Shea, Dearborn Heights,

Mich.

[73] Assignee: Gam Rad, Inc., Detroit, Mich.

[22] Filed: Nov. 3, 1972 [21] Appl. No.: 303,631

[52] US. Cl 731/61 R, 137/238, 137/240, 250/239, 350/63, 356/208, 356/246 [51] Int. Cl. G01n 21/26, G02b [58] Field of Search 137/240, 238; 73/36, 61 R, 73/DIG.11, 355; 350/63 X; 251/118, 61;

[56] References Cited UNITED STATES PATENTS 1,924,139 8/1933 Thomas ..250/218X 1 Jan. 21, 1975 2,185,361 1/1940 Townc 250/218 3,398,023 8/1968 Jacobsen et al. 350/63 X 3,404,284 10/1968 Doolittle 350/63 UX 3,453,049 7/1969 Wager, Jr. 350/63 X 3,628,028 12/1971 Thorsheim 2.50/23) X Primary ExaminerAlan Cohan Assistant ExaminerR0bert J. Miller Attorney, Agent, or Firm-Zwcrdling, Maurcr, Diggs & Papp [57] ABSTRACT A turbidimeter 0r fluid analyzer having the light transmitting windows maintained clean by apparatus directing a flow of fluid thereupon.

10 Claims, 5 Drawing Figures FLUID ANALYZER WITH SELF-CLEANING VIEWING WINDOWS SUMMARY BACKGROUND OF THE INVENTION The present invention relates to turbidimeters and more particularly to a turbidimeter having apparatus for cleaning the light transmitting windows.

With the recent emphasis on pollution control the potential applications for turbidimeters or fluid analyzers as fluid flow monitors has increased. In some applications, however, the fluid to be monitored or analyzed can be such as would deposit particles on or eventually coat the windows; clearly the effectiveness of the device could be maintained only through periodic cleaning. In the present invention, this problem is solved by utilizing a flow of fluid over the window to clean and/or insulate the window from contamination.

Therefore, it is an object of the present invention to provide a new and improved turbidimeter having means for maintaining the light transmitting window clean.

In one form of the invention the window is maintained clean by providing, in a sense, a curtain of water or other clean fluid, different from the monitored or analyzed fluid, across the window to maintain a thin protective film or barrier thereacross. Thus it is another object of the present invention to provide a turbidimeter of the above described type having apparatus for providing a curtain or film of fluid, different from the monitored fluid, across the light transmitting windows to maintain them clean.

In another form of the invention, apparatus is provided to increase the flow of the monitored fluid on the area adjacent the windows and then to maintain the windows clean by the velocity of the fluid or in a different form by turbulence. Thus it is another object of the present invention to provide a turbidimeter having apparatus for cleaning the light transmitting windows by using the monitored fluid and by increased velocity across the windows and/or turbulence at the windows. It is still another general object to provide for an improved turbidimeter.

Other objects, features, and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view taken generally along the lines 11 of FIG. 2 of a turbidimeter having apparatus for providing a film of fluid across the transmitting windows, which film of fluid is different from the fluid being analyzed;

, FIG. 2 is a sectional view of a portion of the turbidimeter of FIG. 1 and taken generally along the lines 22 of FIG. 1;

FIG. 3 is a fragmentary view of a modified flow tube for a turbidimeter similar to that of FIG. 1 having a construction for providing a separate flow of fluid across the transmitting windows which is the same fluid as that being analyzed;

. FIG. 4 is a fragmentary view of a different, modified flow tube in which all of the fluid to be monitored is directed through a restriction adjacent the windows; and

FIG. 5 is a fragmentary sectional view of still another form of the invention for providing a restriction adjacent the transmitting windows.

Looking now to FIG. 1, a turbidimeter or fluid analyzer is generally shown and is indicated by the numeral 10 and includes a flow tube assembly 12 and a support housing 14. The tube assembly 12 includes a main outer tube 16 which has a flange 18 at its outlet end and a threaded adaptor 20 secured to its inlet endflhe adaptor 20 receives the end of a pipe 22.

The main tube 16 has a necked down portion 24 intermediate its ends, which necked down portion is provided with a plurality of

flats including flats

26 and 28 which facilitate the mounting ofa light source assembly 30 and a sensor assembly 32. The light source assembly 30 includes a lamp 33 which can be energized in a suitable source of electricity and the output of which can be sensed and regulated via a regulator 34; regulator 34 can be of a type well known in the art and hence the details thereof have been omitted for purposes of simplicity. The lamp 33 is connected to transmit its light through a lense assembly 36 and thence into the necked down portion 24 of the flow tube I6 via a window assembly 38. The window assembly 38 is connected to the flat portion 26 and includes a window 40 which has its inner surface generally flush with the flat portion 26.

As can be seen from FIG. 2, the flat portion 28 is at quadrature with flat portion 26. Looking again to FIG. 1, the sensor assembly 32 is connected to a lense assembly 42 which in turn is connected to a window assembly 44. The window assembly 44 is connected to the flat portion 28 and includes a window 46 which has its inner surface generally flush with the flat portion 28. The sensor assembly 32 includes a suitable photoresponsive member and can be connected to suitable output indicating apparatus (not shown) whereby an indication of the turbidity of the fluid being analyzed can be obtained. The output indicating apparatus can be of construction well'known in the art and hence a description thereof has been omitted for purposes of simplicity.

As noted the turbidimeter 10, having the light source and photosensitive member at a relative angle of operates on the Tyndall Effect. It should be understood, however, that the present invention is not limited to Tyndall Effect turbidimeters but can be used generally with any turbidimeter or fluid analyzer having a window exposed to the fluid being analyzed. A window assembly 47 (FIG. 2) provides for pass through of the light from source 30 and minimizes errors from reflected light from that opposite wall.

An inner smaller diameter tube 48 has an enlarged end portion 50 which is snugly, sealingly held to the inside diameter of adaptor 20. The tube 48 extends generally up to the

windows

40 and 46 and is in direct communication with the pipe 22 such that the fluid to be analyzed will be carried by the inner tube 48 and transmitted into the main tube 16 at the

windows

40 and 46 whereby the fluid will be exposed for analysis via the light means 30 and sensor means 32.

The inner tube 48 has a reduced diameter portion 52 which defines an annular passageway 54 with the main tube 16; the inner tube 48 terminates in a reduced diameter end portion 56 which is located in close clearance relation to the necked down portion 24 and defines therewith a restricted passageway 58 which terminates just ahead of the

windows

40 and 46.

The end portion 56 is also provided with flats similar to the reduced diameter portion 24.

An inlet pipe 60 is connected to the main tube 16 at a position to communicate the annular passageway 54 and a source 62 of fluid. The source 62 can be varied to vary the pressure of the fluid to regulate the velocity of fluid across the

windows

40 and 46. While the preferred fluid from source 62 could be clean water any fluid which would not adversely affect the analysis of the fluid from pipe 22 can be used.

In operation, the clean fluid from source 62 is directed to flow across the

windows

40 and 46; the pres sure of the clean fluid from the source 62 is selected such that the velocity of clean fluid from the restricted passage 58 is sufficient to provide a thin film or curtain across the

windows

40 and 46 to, in a sense, insulate them from the fluid being analyzed. The pressure at the exit of passageway 58 is also selected to be sufficiently high to assure that the fluid to be analyzed, from pipe 22, will not back up into passageway 54. Thus with the design of FIG. 1, the

windows

40 and 46 will be main tained clean from contamination by the film or curtain of clean water or other suitable fluid from source 62.

in the embodiments of FIG. 3-5 a separate fluid is not utilized and the windows are maintained clean providing a curtain of film of the fluid being analyzed at an increase in velocity in the area adjacent the window so that the windows are maintained clean by a scrubbing action caused by the increased velocity and/or by turbulence. In the description of the embodiments of FIG. 3, 4 and 5, elements similar to like elements in the embodiment of FIG. I and 2 have been given the same numeral designation with the addition of the letter postscripts a, b and c, respectively.

Looking now to FIG. 3, the need for fluid source 62 has been eliminated and pipe 60a is now connected as a shunt from between passageway 54a and pipe 22a. Thus, a portion of the fluid to be analyzed flowing in pipe 22a is bypassed into passageway 54a while the remainder flows through inner tube 48a. The remainder of the construction is generally the same as that of FIG. 1. It is known that the velocity of a fluid in a pipe is greater at the center than at the outer extremity. However, by use of the fluid flow through the restriction (similar to restricted passageway 58 of FIG. 1) the velocity of the fluid is increased over what it would have been if the outer tube 12a had been used alone in the conventional manner. Thus, the fluid in passage 54a is discharged adjacent the windows and at an increase in velocity; hence, the windows are maintained clean by the scrubbing action of the film of fluid flowing thereacross at an increase in velocity.

In the embodiment of FIG. 3 an auxiliary pump 67 is supplied in line 60a to raise the pressure in line 60a to a level to provide the desired flow through the restriction (similar to 58) for the cleaning purpose noted. Alternatively a flow restriction could be provided (in lieu of pump 67) in tube 50a to provide the necessary differential in pressure between the fluid on tube 50a and that in tube 60a to provide the desired flow through the restriction (similar to 58).

Looking now to FIG. 4, again the fluid to be analyzed is used to maintain the windows clean. Here the inner tube 48b is blocked at opposite ends by plugs 64 and 66 and all of the fluid to be analyzed is transmitted to the passageway 54b and pipe 60b. Now all of the fluid to be analyzed is transmitted through the restricted passageway 58b and flows across the windows 40b and 46b at an increased velocity. In addition because the fluid from restricted passageway 58b includes all ofthe fluid flowing through the main tube 12b and the restricted passageway 58b opens abruptly into an enlarged volume as defined by the necked down portion 24b adjacent the windows 40b, 4612, there will be turbulence in this enlarged volume. The turbulence and increase in velocity across the windows 40b, 46b will assist in maintaining the windows 40b, 46b clean.

In the embodiment of FIG. 5 the inner tube has been omitted and now all of the fluid to be analyzed flows directly through the inner tube 12:- from the inlet pipe 22c. However, a flow restrictor 68 is supported generally in the necked down portion 24c adjacent the windows 40c, 46c and defines a restricted passageway 58:" In the embodiment shown in FIG. 5 the flow restrictor 68 is generally conically shaped and is supported in the main tube via a plurality of legs 70. The restrictor 68 terminates at its large or base end in a plurality of flats 72 having an outer contour generally similar to the contour of the confronting surface of the flated, necked down portion 24c. The action of the restrictor 68 is similar to that of the closed inner tube 48b of FIG. 4 in that it provides for both an increase in velocity of fluid across windows 40c, 46c and also provides for turbulence in that area. This action will assist in maintaining the windows 40c, 46c clean.

Note that the analysis or indication or turbidity is not affected by the velocity of the fluid or by the turbulence of the fluid and hence the apparatus of the embodiment of FIGS. l5 will not affect the analysis being made.

Thus, in each of the embodiments shown, there is provided apparatus for self-cleaning of the windows whereby the frequency of maintenance can be reduced.

While it will be apparent that the preferred embodiments of the invention disclosed are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the invention.

I claim:

1. A fluid analyzer comprising an annular, elongated flow tube, said tube having at least one window whereby the fluid can be analyzed, and flow means operatively connected to said flow tube for directing fluid flow across the surface of said window in said tube whereby said surface of said window will be maintained clean, said flow tube including means for transmitting the fluid to be analyzed through a first passageway past said window whereby the analyzed fluid can be viewed and with said flow means comprising separate passage means for directing fluid across the surface of said window via a second passageway separate from said first passageway, said flow means comprising a different annular elongated tube supported within said flow tube and defining with said flow tube said first and second passageways.

2. A fluid analyzer comprising a flow tube, said tube having at least one window whereby the fluid can be analyzed, and flow means operatively connected to said flow tube for directing fluid flow across the surface of said window in said tube whereby said surface of said window will be maintained clean, said flow tube including means for transmitting the fluid to be analyzed through a first passageway past said window whereby the analyzed fluid can be viewed and with said flow means comprising separate passage means for directing fluid across the surface of said window via a second passageway separate from said first passageway, said flow means comprising shunt means for receiving a portion of the fluid to be analyzed and directing that portion across the surface of said window.

3. A fluid analyzer comprising a flow tube, said tube having at least one window whereby the fluid can be analyzed, and flow means operatively connected to said flow tube for directing fluid flow across the surface of said window in said tube whereby said surface of said window will be maintained clean, said flow means directing fluid to be analyzed across the surface of said window.

4. The analyzer of claim 1 with said flow means transmitting all of the fluid to be analyzed.

5. A fluid analyzer comprising a flow tube, said tube having at least one window whereby the fluid can be analyzed, and flow means operatively connected to said flow tube for directing fluid flow across the surface of said window in said tube whereby said surface of said window will be maintained clean, said flow means comprising flow restrictor means located approximate to said window for providing fluid flow at an increased velocity.

6. The analyzer of claim 5 with said flow restrictor means defining a restricted passageway and with said tube adapted to transmit all of the fluid to be analyzed through said restricted passageway.

7. The analyzer of claim 6 with said restricted passageway terminating adjacent said window and communicating therewith a substantially increased volume whereby the fluid flow will be turbulent in the vicinity of the surface of said window.

8. The analyzer of claim 7 with said flow restrictor means comprising a closed tube supported within said flow tube and located to define said restricted passageway.

9. The analyzer of claim 7 with said flow restrictor means comprising a generally conically shaped member located to define said restricted passageway with the base downstream.

10. The fluid analyzer of claim 9 with said base having a contour similar to the contour of the confronting

Claims

10. The fluid analyzer of claim 9 with said base having a contour similar to the contour of the confronting surface of said flow tube.