US3037459A

US3037459A - Balanced pressure rotor vane

Info

Publication number: US3037459A
Application number: US761526A
Authority: US
Inventors: Richard M Nelden
Original assignee: American Radiator and Standard Sanitary Corp
Current assignee: American Radiator and Standard Sanitary Corp
Priority date: 1958-09-17
Filing date: 1958-09-17
Publication date: 1962-06-05
Anticipated expiration: 1979-06-05
Also published as: GB931406A

Description

June 5, 1962 R. M. NELDEN 3,037,459

BALANCED PRESSURE ROTOR VANE Filed Sept. 17, 1958 2 Sheets-Sheet 1 fizz-=1.

BY 5/07 4 40/450, (.660/5 W /e45 June 5, 1962 Filed Sept. 17, 1958 R. M. NELDEN 3,037,459

BALANCED PRESSURE ROTOR VANE 2 Sheets-Sheet 2 INVENTOR. 2/6/7420 M NELOA/ nit States 3,037,459 BALANtIED PRESSURE RQTUR VANE Richard M. Nelden, Birmingham, Micln, assignor to American Radiator & Standard Sanitary Corporation, New York, N.Y., a corporation of Delaware Filed Sept. 17, 1958, Ser. No. 761,526

6 Claims. (Cl. 13--1l5) My invention relates to fluid couplings and more particularly to an improved coupling wherein the fluid energizing vanes of the impeller, or the energy absorbing vanes of the turbine, or both, are provided with spaced apertures to reduce the differential of pressure exerted on opposite sides of the vanes thereby reducing stresses exerted on the vanes.

In the operation of fluid couplings a fluid energizing impeller connected to a driving member is associated with a turbine or runner connected to a driven member. The impeller and turbine members have vaned concave channels which cooperate to transfer torque from the driving member to the driven member.

The vanes of the impeller force the fluid to rotate with the impeller shell and energy is imparted to the fluid as it is thrown radially outwardly by centrifugal force developed by rotation of the impeller. The shell of the impeller guides the circulating liquid and directs it to flow axially as it is leaving the impeller. Conversely the shell of the turbine or runner member guides the liquid and redirects it to flow radially inwardly. The circumferential circulation of the fluid impinges upon the vanes in the turbine whereupon energy is extracted from the liquid as it is forced to flow radially inwardly in the turbine or runner. The liquid flowing radially inwardly in the turbine is again deflected axially and is directed to flow into the impeller. The liquid is thus circulated between the impeller and turbine members, energy being imparted to the liquid by the impeller and absorbed therefrom by the turbine.

in the operation of fluid couplings the sides of the impeller vanes which impart energy to the circulating fluid are subjected to heavy fluid pressures and loadings, andthe reverse sides of the vanes are subjected to low fluid pressures or are substantially unloaded and as a result of this differential pressure relatively high stresses are exerted upon the vanes. The same is true of the turbine vanes through which torque is absorbed from the circulating fluid and is transferred to the driven member. One side of the turbine vanes are thus heavily loaded and the other side of the vanes are subjected to very light or substantially no loading. The impeller and turbine vanes are thus stressed as beams and in fluid couplings which transmit high horsepower the vanes are subjected to both high bending and centrifugal stresses.

In addition the vanes of fluid couplings are subjected to impact loads or shock stresses as the vanes of the impeller move circumferentially relative to the vanes of the turbine thereby slicing through a body of liquid due to slippage in the coupling.

I have found that the bending loads and shock stresses exerted ,on the impeller and turbine vanes of fluid couplings can be prevented from exceeding predetermined safe values by providing apertures of calibrated sizes in the working faces of the vanes to reduce high fluid pressures exerted on the working faces of the vanes. Vane stresses can thus be materially reduced.

An object of my invention therefore resides in the provision of an improved method of forming fluid coupling vanes in such a manner that the maximum loading and the stresses to which the vanes are subjected can be prevented from exceeding predetermined safe limits.

A further object of my invention is to provide a fluid coupling having vanes of improved design.

Another object of my invention resides in the provision of an improved fluid coupling wherein the vanes of the impeller and turbine members are selectively aperturcd to function as check valves or pressure equalizing ports to reduce the maximum fluid pressure to which the vanes are subjected.

Still a further object of my invention is to provide an improved fluid coupling wherein the vanes are apertured to reduce the pressure exerted on the Working side of the vanes thereby maintaining the maximum loading to which the vanes are subjected within safe limits.

Another object of my invention resides in the provision of angularly related apertures through the vanes of impeller or turbine members or both, the angularity of the apertures functioning to control the quantity of liquid bypassed through the vanes in proportion to the pressure exerted within the fluid coupling.

A further object of my invention is to improve the efficiency of operation of fluid couplings by reducing cavitation within the fluid circuit by progressively by passing through the vanes increased quantities of fluid in proportion to increases in fluid pressure exerted on the working faces of the vanes.

Yet another object of my invention resides in the provision of an improved fluid coupling wherein selectively spaced vanes are provided with apertures of graduated sizes to avoid the development in the circuit of fluid pressures exceeding safe maximum values.

Other objects and advantages of my invention will be apparent from the following description, considered in conjunction with the accompanying drawings submitted for purposes of illustration only and not intended to define the scope of the invention, reference being had for that purpose to the subjoined claims.

In the drawings wherein similar reference characters refer to similar parts throughout the several views:

FIGURE 1 is a sectional view of a fluid coupling embodying my invention;

FIG. 2 is a perspective View of one of the vaned members of my improved fluid coupling illustrating one desirable disposition of pressure relieving apertures in the vanes thereof;

FIG. 3 is a fragmentary view similar to a portion of FIG. 2 illustrating a modified form of my invention;

FIG. 4 is a sectional view taken substantially on the line 4 4 of FIG. 3 looking in the direction of the arrows, and illustrating the angular disposition of the apertures illustrated in FIG. 3;

FIG. 5 is a view similar to FIG. 3 illustrating a further modified form of my invention; and

' FIGS. 6 and 7 are fragmentary views illustrating further modified forms of the invention.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of be ing practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring now more particularly to FIG. 1 it will be observed that a driving shaft 10 is operably connected to drive an impeller or primary rotor 12 secured thereto in any convenient manner as by hub 14 carried by the impeller. The impeller 12 has a concave-shaped shell 16 terminating in a radially extended flange 18. A turbine 20 has a concave-shaped shell '22 positioned in confronting relation to the impeller shell 16. The turbine 20 is con- 3 nected through a hub 24 with a driven shaft 26 aligned with the driving shaft 10.

Inner and outer casings 28 and 30 having radially outwardly extended flanges are secured to the flange 18 of the impeller shell 16 by bolts 32. Part of the stationary bearing housing 36 extends into the outer casing 30 and supports the inner turbine bearing 37. Tue inner casing 28 is contoured to overlie the turbine shell 22 and has a close running fit with respect to the bearing housing 36 to provide a substantially fluid tight joint therewith. Apertures 39 in the outer periphery of the casing 28 are provided to permit the escape of liquid from the fluid circuit to a scoop tube chamber 41 between the casings 28 and 30. An adjustably positioned scoop tube 43 extended into the chamber 41 is provided to establish the desired degree of filling in the circuit, thereby controlling the turbine output speed and torque.

The impeller and

turbine shells

16 and 22 respectively are provided with radially extended vanes and 42 to impart energy to and absorb energy from the liquid circulating in the fluid circuit defined by the impeller and

turbine members

12 and 20* respectively. The impeller and turbine vanes 40 and 42 are provided with confronting

shroud members

44 and 46 to guide the circulating liquid flowing from the impeller to the turbine and from the turbine back to the impeller.

It will be understood that the impeller and turbine members may be formed in any desired manner as by machining, Welding, casting or stamping, and that the

vanes

40 and 42 may be formed integrally with the

shells

16 and 22 or may be secured thereto in any desired manner. Also it will be apparent that the

shroud members

44 and 46 may be employed to assist in guiding the fluid, or if desired they may be omitted if the design is properly modified.

As shown in the embodiment of my invention illustrated in FIG. 1 the impeller and

turbine vanes

40 and 42 have a plurality of spaced

apertures

48 and 50 to permit the circulating liquid to flow through the vanes from the side of the vanes subjected to the liquid pressure in imparting energy to the liquid or absorbing energy therefrom to the back or non-pressurized side of the vanes to relieve the force exerted on the vanes by fluid pressure exerted by the circulating liquid on the working face of the vanes. A suflicient number of

apertures

48 and 50 in the impeller and turbine vanes 49 and 42 of suitable size may be employed to permit a suflicient flow of liquid through the vanes to relieve or reduce the pressure on the working face of the respective vanes to maintain the stresses imposed within desired safe limits thereby preventing the development of undesirable bending stresses.

FIG. 2 illustrates a desirable embodiment of my invention as applied to an impeller 12. It will be observed that a plurality of apertures 48 are positioned in the vanes 40 adjacent the outer profile 52 of the impeller shell 16. The apertures 48 may be of graduated sizes and may be present in suflicient number to relieve excess fluid pressure exerted on the outer periphery of the impeller. It will be apparent that successively spaced impeller vanes 40 may have different patterns of apertures to relieve fluid pressure to a desired degree. For example a symmetrical group of vanes 40 may have a cluster of several apertures and another symmetrical group of vanes 40 may have a group of a different number of apertures which may also be of different size, and groups of apertures varying in number and size may be employed in adjacently positioned vanes to break up vibrational stresses. The same is true with respect to the vanes 42 of the turbine. It will also be apparent that the same grouping and size of apertures may be formed in all of the vanes of the impeller or turbine members, or both.

FIG. 3 illustrates my invention applied to the turbine 20. It will be noted that the turbine vanes 42 in this embodiment are provided with apertures 50 spaced along the vanes adjacent the juncture of the vanes with the shell i 22. Apertures of graduated sizes may be employed and the apertures may be more closely spaced relative to each other in the areas subjected to the highest pressures. This expedient may of course be resorted to with respect to both the impeller and turbine.

The

apertures

48 and 50 may, as shown in FIG. 4 be slanted or inclined opposite to the direction of movement of the liquid relative to the vanes as shown by the arrow 56 to retard or delay the flow of power transmitting liquid therethrough until the pressure exerted on the working faces of the vanes reaches a substantially predetermined value. The

apertures

48 and 50 reduce the pressure loads and impact stresses exerted on the impeller or

turbine vanes

40 and 42 respectively to maintain the stresses within workable limits. When low or medium pressures are exerted on the working faces of the vanes the forward inclination of the apertures through the vanes retard or delay the flow of fluid through the vanes at slow speeds. As increasing pressures are developed within the fluid circuit and exerted on the working faces of the vanes, fluid flows through the forwardly inclined apertures, and the degree of flow is dependent in part on the pressures exerted. Where this expedient is resorted to, the fluid pressure exerted on the impeller and turbine vanes can be controlled by permitting the escape of fluid through the vane when fluid pressure reaches a predetermined value, thereby reducing the stresses to which the vanes are subjected.

The use of apertures through the vanes alters the natural frequency of the vanes to provide stronger impeller and turbine members which are less susceptible to vibrational stresses.

Referring to FIG. 5 it will be observed that apertures 50 of graduated sizes may be formed in the turbine vanes 4-2 to maintain substantially constant pressure over the entire working face of the turbine vanes 42. While this expedient reduces the pressure within the working circuit and therefore changes the torque transmitting characteristics of the unit, it does prevent subjecting the vanes to undesirable stresses. The impeller vanes 40 may of course be similarly treated with apertures of graduated sizes spaced to maintain substantially uniform pressure over the Working faces of the vanes. The use of apertures to relieve pressure during certain phases of operation of the unit also functions to reduce cavitation.

While my invention has been illustrated as applied to several types of pressure relieving configurations, it will be apparent that it is susceptible to many changes, in the number of apertures employed, in the disposition of the apertures in the areas of the vanes subjected to predeter mined pressures, and in their angularity through the vanes to provide desired results.

It will also be apparent that instead of employing apertures extending through the body sections of the vanes, notches 50 in the edges of the vanes 40 may be employed as shown in FIG. 6, or notches or circumferentially extending grooves may be formed in the shell 16 as shown at 62 in FIG. 7 to permit by-passing a portion of the circulating fluid to the opposite sides of the vanes to relieve excess pressures, thereby reducing the danger of subjecting the vanes to excess pressures. It will of course be apparent that these expedients can be resorted to with respect to the impeller or to the turbine members.

I claim:

1. In a fracture-resistant rotor for a fluid coupling, the rotor having an annular shell of toroidal section with substantially flat vanes extending generally radially of the shell and having the plane surfaces thereof disposed generally axially with respect to the shell, each of the vanes being of generally semi-circular configuration and having a free, generally straight edge defining a generally radially disposed inlet edge portion and a generally radially disposed outlet edge portion, the improvement of a multiplicity of apertures extending through each of the vanes and formed as a pattern, and adjacent vanes having differcut aperture patterns, whereby fluid is enabled to flow through the vanes from the high pressure face to the low pressure face along portions of the vanes subjected to highest pressures, reducing pressure imbalances and the magnitude of bending stresses and detuning the vanes to break up vibrational stresses incurred while the rotor is running at speed and load conditions tending to put the vanes in resonant vibration.

2. The combination defined in claim 1 wherein the apertures have fluid inlets formed in the high pressure vane faces and fluid outlets formed in the low pressure vane faces, with said fluid outlets being spaced nearer the outlet edge portions of the vanes than said aperture fluid inlets.

'3. In a fracture-resistant rotor for a fluid coupling, the rotor having an annular shell or toroidal section with substantially flat vanes extending radially of the shell and having the plane surfaces thereof disposed generally axially with respect to the shell, each of the vanes being of generally semi-circular configuration and having a free, generally straight edge defining a generally radially disposed inlet edge portion and a generally radially disposed outlet edge portion, the improvement of a multiplicity of apertures extending through each of the vanes and spaced around the curved peripheral portions of the vanes adjacent the shell, said apertures being formed as a generally semi-circular pattern extending substantially from the radial inlet edge portion of the vanes to substantially the radial outlet edge portion thereof, and the apertures within the pattern being different in adjacent vanes, whereby fluid is enabled to flow through the vanes from the high pressure face to the low pressure face along portions of the vanes subject to highest pressures, reducing pressure imbalances and the magnitude of bending stresses and detuning the vanes to break up vibrational stresses incurred while the rotor is running at speed and load conditions tending to put the vanes in resonant vibration.

4. The combination defined in claim 3 wherein the apertures have fluid inlets formed in the high pressure vane faces and fluid outlets formed in the low pressure vane faces with said fluid outlets spaced nearer the outlet edge portion of the vanes than said aperture fluid inlets.

5. In a fracture-resistant rotor for a fluid coupling, the rotor having an annular shell of toroidal section with substantially flat vanes extending generally radially of the shell and with the plane surfaces thereof disposed generally axially With respect to the shell, each of the vanes being of generally semi-circular configuration and having a free, generally straight edge defining a radially disposed inlet edge portion and a generally radially disposed outlet edge portion, the improvement of a multiplicity of apertures extending through the vanes and spaced over the vanes in a semi-annular pattern, said patterns extending from the inlet edge portions of the vanes to the outlet portions thereof, and the apertures within the patterns being diflerent in adjacent vanes, whereby fluid is enabled to flow through the vanes from the high pressure face to the low pressure face along portions of the vanes subjected to highest pressures, reducing pressure imbalances and the magnitude of bending stresses and detuning the vanes to break up vibrational stresses incurred while the rotor is running at speed and load conditions tending to put the vanes in resonant vibration.

6. The combination defined in claim 5 wherein the apertures have fluid inlets formed in the high pressure vane faces and fluid outlets formed in the low pressure vane faces, with said fluid outlets spaced nearer the outlet edge portions of the vanes than said aperture fluid inlets.

References Cited in the file of this patent UNITED STATES PATENTS 2,334,573 Miller Nov. 16, 1943 2,357,485 Miller Sept. 5, 1944 2,421,360 Swennes May 27, 1947 2,494,539 Bolender Ian. 17, 1950 2,556,666 Snyder June 12, 1951 2,672,098 Bilsky Mar. 16, 1954 FOREIGN PATENTS 256,647 Great Britain Oct. 21, 1926 754,055 Great Britain Aug. 1, 1956 875,522 France June 22, 1942