US2017311A

US2017311A - Flow-responsive device

Info

Publication number: US2017311A
Application number: US237879A
Authority: US
Inventors: Jacobson Eugene
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-12-05
Filing date: 1927-12-05
Publication date: 1935-10-15
Anticipated expiration: 1952-10-15

Description

or.15,1935.- EJACOBSOQ 2,017,311

-FLOW RESPONSIVE DEVICE 'Filed Dec. 5, 1927 2 sheets-sheet 1 Oct. 15, 1935.

El JACOBSON FLOW RESPONSIVE DEVICE 2 Sheets-Sheet 2 F'il'ed Dec. 5, 1927 INVENTOR Patented Oct. 15, 1935r UNITED STATES PATENT OFFICE 2,017,311V FLOW-RESPONSIVE DEVICE l Eugene Jacobson, San Francisco, Calif. Application Deember 5, 1927, serial No. 237,879

12 claims. rc1. 137-156) i My invention relates to flow-responsive devices and to a variable` venturi incorporated therein; and is intended especially for combination with gas water heaters of the instantaneous or ow- 5 controlled type, wherein'the fuel valve is operated by the flow of water through the heater.

It is the practice in a common form of domestic Y water heater, to control the gas fuel supply valve by the flow of water through theA heater so that l the burner flame is turned on or oil in response to, commencement or cessation of ow of water through the heater. Practically no allowance is made for variations in flow intermediate between zero and maximum demand. In and of l themselves, these flow-controlled valves are not capable of regulating the gas fuel supply in proportion to the water demand throughout the range of dfmand. In actual practice, unless a complicated and costly thermostatic control is 20 superimposed, the effect is to overheat the Water while the demand is small, and to underheat the wat r when a larger flow is used. No entirely satisfactory means has yet been evolved to make lthese automatically controlled valves proportion- 25 ately eiective over a wide range of demand, and in practice the heater will not function at all when only a small amount of water is being drawn.

It is an object of my invention to practically obviate any and all the disadvantages hereto- 30 fore inherent in the flow-controlled fuel valves of water heaters. y My invention is4 applicable morebroadly than to Water heaters alone.v .In general, it is an object of my invention to provide an improved now-actuated means for operating valves. It is an object of my invention to provide a flow-actuated device having a maximum eiective range; and it is an important further object of my invention that this large range be attainable at the expense neither of excessive resistance to ilow nor of lack of power of actuation.

It is an object of my invention to provide a venturi which is effective over a Wide range of variable flow. The signicance of this object of my invention is emphasized by the fact that a venturi is inoperative unless the flow is sufcient to keep it full of liquid, and is practically inoperative unless small enough to secure a 50 high velocity of ilow therethrough; while if the venturi is made too small, its resistance to large uid iloW is prohibitive. It is an object of my invention to provide a venturi which may adjusted to accommodate diierent volume.' of ow, 56 and it is a further object of my invention to provide automatic means for so adjusting the venturi.

It is an object of my invention to teach the design'of flow-responsive devices having an improved means for providing any desired ow-re- 5 sponsive characteristics. `It is a further object of my invention to provide a ow-respon'sive device of the character set forth with adjustments for altering certain of its characteristics.

In the interest of conciseness, the above objects have been condensed. Various subdivisions and combinations of these objects are to be expected within the purview of my invention. Further and ancillary ,objects of my invention will be suggested in the following description and in the use of the device of my invention.

Referring to the drawings:

Fig. l is a schematic minied front elevation of a water heater embodying my invention. Fig.

2 -is a median'longitudinal section of the valve- 20 operating portion of my invention removed from the water heater. Fig. 3 is a section similar to that of Fig. 2 of a modified form of my invention. Figs. 4 and 5 are elevations of the tip fragments of two different shaped cores alternative to that illustrated .in Fig. 3.

A water heater (Fig. 1) of the instantaneous or flow-controlled type, is formed essentially of a casing l,`a water coil 2, a main gas burner 3, and a pilot burner lshown dotted in Fig. l) A Water outlet pipe 5 is provided from the heater, and is connected in conventional manner to the hot-water Ytaps served by the heater.` A cold Water inlet pipe 6, 6. is adapted to serve the heater from the city or other pressure mains. A gas in- .35 let pipe 1 is provided to supply fuel to the burners 3 and VIl, and aI gas valve 8 is provided -in the supply line 1 for regulating the fuel supply to the burners. These elements are conventional and well-known in the water heater art, and need not be described in detail.

Flow-responsive means are provided for controlling the valve 8 to regulate or determinethe fuel supply and therefore the heat input tothe water heater. Interposed in the pipe-line 6, 5 '45 supplying water to the heater, is a Venturi passage (Fig. 2 or 3) formed of a pipe-like cast or otherwise suitably formed member l0 having its bore or passage gradually and smoothly reduced from a maximum at each end to a minimum at the throat or constricted portion Illa of the venturi. Wheneverl Water is drawn through the heater, it must ow through the'venturi.f This ow through the venturi causes a reduction of pressure at the throat Illa, and produces a sharp low pressure end of the cylinder.

of pressure. and therefore the force tending to of the venturi; while the pressure at all other points s uch as at ahot water tap in. the,I line 5, remains almost unchanged at the normal city water pressure. It is emphasized that the Venturi action is not a. throttling effect and that'the Venturi pressure difference would be set-up even though the pressure at the hot water tap were no less than that in the water mains. It is one important object ofmy invention to avoid undue' loss .of pressure between the mains and the hot water tap.

Pressure-responsive i means are provided for harnessing this Venturi effect. An expansiblefluid chamber (Fig. 2'or 3) is formedby a cast or otherwise suitably formed cylinder I2 having a removable head I2'; 'and the movable wall of theexpansible-fluid chamber is constituted by a piston or plunger I3. The plunger I 3 is preferably fabricated of a pair of .discs I 3 and I3' centrally bored and i threaded to r screw upon the threaded portion I4' of aplunger rod I4. Two annular plunger leathers I 3"' and I 3"' are clamped between the discs and extend out'into sealing engagement with the wall of the cylinder I2. The plunger is assembled byfirst screwing one disc I3 up to the desired point of the threaded portion I4', then positioning the two leathers, and then screwing the other disc I3" tight up against them. The threaded portion I4" is made long enough to permit adjustment of the position of the plunger along the rod. The discs have their opposed radial faces shaped to form a central cup or stuiling boxto retain string or other suitable packing I37 for preventing leakage along the rod I4.

An ingenious arrangement of pressure-respon sive means has been selected as most suitable for the purposes of this invention. An eccentric Vthreaded opening in the head I2' of the cylinder,

if provided to receive the end of the water supply pipe 6 from the city mains. The head end of the cylinder is thus at all times exposed` to the pressure in the water mains, and is therefore the high pressure end of the cylinder. A central threaded opening in the head I2', is adapted toreceive the threaded lower high pressure end of the Venturi member I0. 'I'he lower or low pressure end of the cylinder I2 is connected by` piping I6; into the throat I0a of the'venturi. The piping I6 is preferably fabricated of small gauge copper tubing and standard connections therefor such as are commonly employed for gasoline lines in automobiles.

AAll water passing through the water heater, must flow into this high pressure end o f the cylinder and out through the venturi, and this ow through the venturi causes the pressure at the throat Illa to drop below that in the high pressure end of the cylinder I2. This reduction of pressure is communicated by the phing IB to the low pressure end of the cylinder, thereby inducing movement of the plunger I3 toward the The reduction PIES- move the plunger, becomes greater as the flow is increased. Conversely, when flow ceases the pressure at the throat Illa becomes equal to the pressure in the city mains, and the pressure on bothj sides of the plunger I3 then becomes equal.

An adjustable helical, spring H between the lowv pressure end of the cylinder and an'adjusting nut I1' on the plunger rod I4' urges the plunger counter to the pressure forces imposed thereon, so that the device will return toward 10 inoperative position as. soon as flow through the venturi is reduced.

. The motion of the plunger I3 is transmitted to the gas valve 8 by the plunger rod I4, th'e lower small diameter end of which extends out through l5 a stumng box I8 in the low pressure end of the cylinder. The plunger rod is in' line with the .stem 8' of the gas valve, so that the gas valve l is opened by movement of the plunger I3 toward the low pressure endl of the cylinder. y 20 The end of the plunger rod I4 outside the stufling box I8 is threaded to receive an internally threaded sleeve I 9 (Fig. 3) which is pro- 'vided to control the clearance between the plunger rod I4 andthe valve stem 8.-'. A lock nut 20 is 25 provided for the sleeve I9.

'I'he Venturi pressure difference is well adaptedA l to actuation of the fuel valve 8, and is found to control the valve over a far greater range of flow l than any 4such device heretofore employed 'in 30 venturi, as exemplified in Figs. 2,3 and 5, the 40,

relative constriction at the throat Illa may be increased or decreased so as to adjust the Venturi effect at will and independently of the ow, by the simple adjustment of moving the core axially in the venturi. While I prefer to employ a ta- 45 pered core and constricted conduit to'form a variable venturi, I recognize that it would be possible to substitute a tapered conduit and bulbous core to produce a Venturi effect.

A slender integral extension 2| of the core 2| 50 extends out beyond .the venturi, and is threaded at its outer end for reception in the threaded bore of a pipe plug 22. A kurled adjusting head 23 is secured to the free end of the extension 2I', and a combined stu'ing box andlock nut 24 is 55' provided to prevent leakage past the pipe plug and to lock the core in adjusted position. 'I'he pipe plug 22 is received in and vsupported by an offset-T pipe fitting 25 which may be cast as shown, orl might be assembled of standard parts 60 by combining a plain T and L. These piping connections are modifiable by the pipe-fitter to suit the particular installation of the device of my invention. i

In the modified embodiment of Fig. 3 the Ven- 65 turi core I4" has no threaded' extension analogous to the portion 2 I and means are provided for automatically moving the core to adjust the size of Venturi passage in response to the flow therethrough. 'I'he Venturi core I4" instead of being 70 manually adjustable,y is formed as an integral extension of the plunger rod I4 and is therefore constrained to move with the plunger I3.

In operation, as now through the-system increases, the plunger I3 is forced downward, there- 75 2,017,311 by partially withdrawing the attached tapered ,core I4" and thus increasing the size of the Venturi passage to accommodate the larger ow. In this form of my invention, movement of the core is automatically controlled by the Venturi pressure difference, and this movement in turn alters the Venturi size. Therefore the movement and pressure variation are intimately interrelated, and are both dependent upon the relative tapers and curvatures of the venturi and core.

By suitably proportioning the curvature and taper of the core, movement of the rod I4 may be madev any desired function of the water ow. In designi ing an automatically variable venturi of this type forany particular application, the proportions of the parts will be determined by the .par-

ticular characteristics desired.` Thus, for example, the movement of the rod I4 may be made directly proportional to or may be made any simple or complex function of the ow by suitably forming the Venturi core. Where large movement of the rod .is desired over any part of its traverse, that part of its taper will be made very gradual, and where small movement is desired, the taper will be made sharper. v

In this particular applicationof the venturi of my invention the following characteristics of motion are desired. No motion at all is desired unj til the water flow exceeds a. leakage dribble. Therefore the maximum diameter of the core I4 is made slightly-smaller thanltheminimum diam- Y eter of the venturi. As soon asthe water flowV exceeds a leakage dribble, a large initial movement of the rod I4 is desired to take up necessary 4 clearance in the valve-operatingmechanism and to open the gas valve to low flame position. Therefore the maximum diameterportion of the core is carried substantially without taper for a.

considerable distance. In order to avoid excessive opening ofthe gas valve, the second stage f movement of the rod I4 must be relatively small for a given increase of water flow. Therefore the tapered portion of the core is made relatively steep. (For any given main pressure and flow, and neglecting friction, the Venturi pressure difference equals K-a-(dlZ-dzZlz; where K is a constant, d1 is the diameter of the Venturi throat and d2 is the diameter of that portion of the core which is at the throat.)

f The spring tension and position of the plunger on the `rod I4, and the clearance between the rod I4 and gas valve 8, may all be adjusted. Where different Venturi characteristics are desired however, a different shaped core must be substituted for the core i4". Before any'particulardesign of a device of my invention is thrown into probe determined by calculating thediameters necessary to produce `the required characteristicsv at several spaced positions of the core. A number of different cores I4a, Mb, etc. .such as are illustrated fragmentarily in Figs. 4 and 5, will ordinarily be supplied with each variable venturi intended for application at different times to actuate different devices. Thus the venturi as a universal device is suitable at one time for example to operate a valve, and at another time to operate a meter, electric switch, or other device; it being necessary merely to substitute a core Ida, Itb, or etc. for the core I4", to-produce the desired modified characteristics. The core Itb vof Fig. 5 is what I call a double or complex core in that two successive or distinct sets of Venturi characteristics are attainable by axially moving either tapered portion z or y into vstriction of said venturi;

. sitioned to form a Venturi passage therebetween;

the eld of the throat I 0a of the venturi. By pluralizng the number of tapers on a single core, it is possible to attain any number of different characteristics in a single instrument; it being necessary merely to alter the limits of movement of the core as by altering the position of the plunger I3 thereon. It is, of course, possible to consider these successive tapers a continuous curve of highly complex form, and to permit a corresponding complex Venturi characteristic; this being governed as before, solely by the limits of axial motion which are set for the core. Having taught the basic principles involved, and at least one specific application of these principles, it is deemedwithin the purview of my invention to alter the shape of core employed, and the limits' of movement of the core to produce the desired characteristics to suit the particular application of the device of my invention. I have described one embodiment of my in- 20 vention in detail, but it is emphasized that this embodiment is illustrative and not inclusive of all the forms my invention may assume. Certain of the objects, or certain portions or combinations of the objects of my invention maybe 25 attained with the use of less than all its advantageous features or with modifications within its purview. lIt is petitioned that my invention be limited only by the claims constituting'lits final determination. y -30 I claim:` l v l. In a variable venturi, resilient means normally tending to increase the eiectiveness of the venturi, and means controlled by said venturi for decreasing the effectiveness of the venturi. 35 2. An automatically variable venturi comprising a conduit member and a lcore member mounted for relative movement to vary the effectiveness of said venturi; the movable one of said members being positioned and arranged for move- 40 ment in the direction of iluid flow through the venturi to increase Venturi effectiveness and counter to said direction of fluid ow to decrease Venturi effectiveness; and means responsive to said uid flow for moving said movable member. 45

3. An automatically variable venturi comprising a conduit member and a core member formed to leave a Venturi passage therebetween and mounted for relative movement to alter the conthe movable one of 50 said members beingl positioned and arranged for movement in the direction of fluid flow through the venturi to constrict the Venturi passage and counter to the direction of, fluid flow to expand the Venturi passage; and means responsive to said fluid flow for moving said movable member. 4.'In combination, a conduit and a movable Venturi-control core within said conduit; said conduit and core being relatively formed and poan expansible pressure chamber having a movable wall of substantially greater area than the maximum eiective cross sectional area of said core, means connecting said chamber in pressureresponsive relation to said venturi, and means connecting said core to said wall for Venturicontrolling operation thereby.

5 In combination, a variable venturi comprising a conduit member and a core member mounted for relative movement to vary the effectiveness of said venturi, a double-acting expansible pressure chamber connected in pressure-responsive relation to said venturi and having a low pressure end, a high pressure end and a movable wall, means extending into said high pressure end and operatively connecting said movable wall to theimovable one of said members.

' 6. In combination, a conduit adapted to conduct iiuid flow .in one direction, a movable Venturicontrol core within said conduit; said conduit and core being' relatively formed and' positioned to leave therebetween a Venturi passage expanding gradually in the direction oi fluid ilo'w4 from a constricted throat to a relatively unconstricted passage, and said conduit and core being relatively tapered and positioned to-decrease constriction of said throat as the core is moved counter to said direction of fluid ilow; an expansible pressure unit including a pressure chamber and a pressurewall movable in response. to change of pressure therein, a pressure connection' from the throat of said venturi to the chamber of said expansible pressure unit, and means connecting said Venturi-control core to the movable wall of said expansiblepressure chamber for actuation thereby.

'7. In combination, an expansible pressure unit including a pressure chamber and a pressure-wall movable in response to change of pressure therein, a movable core member, connecting means con nesting said core member to the movable wall of said expansible pressure chamber vfor longitudinal movement thereby, a conduit surrounding said core member; said conduit and core member being relatively formed positioned and tapered to leave a Venturi passage with characteristicconstricted throat therebetween; the relative position, taper anddirection of taper between said conduit and core member being such that movement oi said core in a direction toward 'said connecting means decreases the throat constriction oisaid Venturi passage. I l

8. An automatically variable venturi including,

a venturi comprising, aconduit adapted to conduct iiuid flow in one direction and a movable Venturi-control core within said conduit.; said conduit and core being relatively formed and positioned and tapered to leave therebetween a Ven7 tuifi passage expanding gradually in the direction of iluld flow from aconstricted throat to a relatively unconstrictcd passage, and said conduit and core having their relative tapcrpositioned and A directed to decrease constriction oI-said throat as the core is movedcounier to said direction of duid flow: :md n differential expansible pressure chamber comprising a chamber and a movable pressure wall dividing said chamber into low and high pressure compartments; said movable pressure wall being larger than the cross-section oi said corc and having substantially equal pressure-ci'- fectivc areas on both sides; a low pressure passage from the throat ci said venturi into said low pressure compartment, a high pressure passage from said venturi atl a relatively unconstricted portion thereof into said high pressure compartment, connecting means extending through said high pressure passage and connecting said core to said movable wall for actuation thereby, and force-exerting means tending to. urge said movable wallv toward the high pressure compartment .15

of said chamber regardless. of whether or not pressure exists therein.

9. A variable venturi comprising a conduit and core therein, relatively-shaped and positioned to form a Venturi passage therebetween, part oi' l0 `which passage is relatively free'and part of which passage is rela-tively constricted to a throat, a

v v double-acting expansible pressure chamber hav- 4ing a low pressure end, a high pressure end anda movable pressure-wall therebetween, said chamlo;

ber being ,positioned with its high pressure end nearer than its low pressure end to the throat of said Venturi passage, means connecting said core Ato said movable. wall for actuation thereby, and

means connecting said chamber into pressure-re- 20 sponsive vrelation with said Venturi passage.

10. Inlvcombination, a variable venturi having a passage .tapering gradually to and from a constricted ithroat, adapted to conduct fluid now-in either direction, movable Venturi-control means 25 associated with said venturi for alteringthe eifectiveness thereof, and owA-responsive means for moving .said vVenturi-control means substantially similarly in response to .change of iiow in eithe direction through saidventuri. 30.

11. vIn combination, a' lvariable venturi compris'- ing a conduit member and. a core member mount' ed for relative movement .to vary the eilectiveness of said venturi, a double-acting expansibleipre's-- sure chamber connected in pressureresponsive-`35 relation to said venturi and having a low pressure end, a high pressure end, and a movable pressure wall therebetween, with substantially equal pressure-eiective areas exposed on its low and high pressure sides., and means -operatively connectingso the movable one of said members to saidmovable wail for actuation thereby. l

12. In combination, a conduit having a. passage part oi' which is relatively freel and part oi which is relatively constricted to form a throat, a double 45 acting expansible pressure chamber having a low pressure end, a high pressure end and amovable wall therebetween, with substantially equal pressureefi'ective areas on its low and high pressure sides, a lead connecting the low pressure end 5o of said chamber into pressure-responsive relation with said constricted throat, a lead connecting-the high pressure end oi said chamber into pressure-l" responsive relation with a relatively free part oi' said passage, and means controlled by said 55 movable wall for altering the constriction oi' said throat. i l l EUGENE JACOBSON.