US2735367A

US2735367A - kenney

Info

Publication number: US2735367A
Authority: US
Publication date: 1956-02-21
Anticipated expiration: 1973-02-21

Description

Feb. 21, 1956 LIQUID Filed June 10, 1952 C. E. KENNEY SUPPLY MEANS FOR A ROTARY MACHINE 3 Sheets-Sheet l Feb. 21, 1956 c. E. KENNEY 2,735,367 LIQUID SUPPLY MEANS FOR A ROTARY MACHINE Filed June 10, 1952 3 Sheets*Sheet 2 Feb. 21, 1956 c, KENNEY 2,735,367

I LIQUID SUPPLY MEANS FOR A ROTARY MACHINE Filed June 10, 1952 5 Sheets-Sheet 3 United States Patent 2,735,367 LIQUID SUPPLY MEANS FOR A ROTARY MACHINE Clarence E. Kenney, Hartlaud, Wis., assignor to Allis- Cllalmers Manufacturing Company, Milwaukee, Wis.

Application June 10, 1952, Serial No. 292,763 Claims. c1. 103-4 This invention relates to a liquid impelling device of novel design and also to a pressure liquid supply system for a rotating machine which system embodies the novel impelling device. More particularly, this invention relates to a novel liquid supply system for a prime mover which system furnishes a sufiicient quantity of low pressure liquid for lubrication purposes and a sufficient quantity of high pressure liquid for operating the hydraulic governing apparatus of the prime mover. The present impelling device and supply system are particularly useful with steam turbines which require a supply of pressure liquid sufiicient to lubricate bearing surfaces and to actuate safety governing units.

Rotating prime movers such as steam turbines have heretofore been lubricated and otherwise supplied with pressure liquid by systems embodying one or more pumps geared to the turbine shaft. However, these known systems have not been entirely satisfactory because of the complicated and costly arrangement of auxiliary apparatus deemed essential to insure the continuous and safe operation of the turbine. 7

Moreover the known systems embodying pumps having an indirect connection with the turbine shaft have proven suificiently troublesome so that attempts have been made to mount at least one of the pumps directly on the turbine shaft and drive the other pumps by suitable auxiliary means. Of course, the particular problems incident to mechanical gearing are solved if all of the oil pumps are driven by auxiliary driving means. However, such an arrangement is only as reliable as the auxiliary driving means and consequently a failure of the auxiliary driving means for any reason while the turbine is running will obviously result in a stoppage of lubrication and possible failure of the bearings. A bearing failure will probably end operation of the hydraulic governing apparatus, with the result that there may be overspeeding and consequent damage to the turbine.

The present invention avoids the aforementioned and other disadvantages by providing an improved system incorporating elements combined for coaction in a novel manner wherein one of the elements may be a double volute centrifugal pump of novel design mountable directly on a prime mover shaft in a manner insuring eflicient and trouble free operation.

The use of a double volute pump in a system of the type mentioned eliminates the necessityfor employing additional cumbersome apparatus for supplying liquid to a machine in considerable volume at two different pres sures. The novel design of this pump also permits the prime mover shaft upon which it is mounted to expand and contract axially without deleteriously affecting the operation of the pump in any manner.

Accordingly an object of this invention is toprovide an improved system for effectively supplying a liquid, such as oil, to a rotating machine at different pressures essential for its safe operation, the system embodying a simplified and novel combination of apparatus minimizing thenumber of elements essential for attaining such operation.

Another object is to provide a novel design of a double volute centrifugal pump which can be operatively mounted directly on the prime mover shaft and which incorporates parts constructed and combined for coaction in an improved manner insuring efficient and trouble free operation.

Still another object of this invention is to provide an improved pump of the type above mentioned wherein the impellers are mounted on the turbine shaft in such a manner that axialexpansion of such shaft causes the impellers and volutes of the pump to move simultaneously with the shaft, thereby maintaining a desired and uniform clearance between the coacting stationary and movable parts.

Other objects and advantages will be apparent from the following description with the accompanying drawings, in which:

Fig. 1 is a schematic illustration of an improved system for supplying a liquid at different pressures to the bearings and regulating apparatus of a rotating prime mover;

Fig. 2 is an enlarged section taken along the line 11-- II of Fig. 3 of the main pump shown in Fig. 1;

Fig. 3 is a plan view of the main pump shown in Fig. 2, a part of the top of the casing being removed;

Fig. 4 is a section of the main pump taken on the line IV-IV of Fig. 2; and

Fig. 5 is a section of line V-V of Fig. 2.

As shown in the drawings in which like elements are designated by like numerals, the system embodying the invention is disclosed as applied (note Fig. 1) to a steam turbine indicated generally at 6 and having a rotating shaft 7 upon which a main liquid supply pump 8 is mounted.

As shown particularly in Figs. 25, pump 8 comprises a stationary casing 9 through which the shaft 7 extends, the casing 9 being anchored on a foundation 11 which is common to the pump 8 and the turbine 6. The casing 9 is partitioned to provide three interior chambers, A, B and C axially spaced from the turbine.

Mounted upon the shaft 7 within the casing 9 is an impeller assembly comprising a runner 12 common to a high pressure impeller 13 and a low pressure impeller 14. This assembly is secured at either of its ends to the shaft 7 by keys 16 and 17, which hold the assembly in a relatively fixed circumferential position thereon. J

A runner face 18, which is disposed adjacent the turbine side of the pump, coacts with a shoulder portion 19 on the shaft 7. An oppositely disposed runner face 21 coacts with a nut 22 which is threaded to the outer end of shaft 7. The nut 22 secures the impeller assembly in a fixed axial position on the shaft 7. Packing seals 23 are located at all joints between the impeller runner 12 and the stationary casing 9.

A high pressure volute 24 is disposed around the high pressure impeller 13, within the chamber A of the casing 9, this volute being provided with packing seals 26 at all joints between it and the high pressure impeller 13. The volute 24 has protruding flange portions 27 which terminally engage thecasing 9 in a manner keying volute 24 against rotation with impeller 13 and shaft 7 while allowing free axial movement of the volute relative to the casing. Volute 24 discharges liquid from two diametrically

opposite discharge passages

28 and 29 into chamber A as shown in Fig. 4.' A conduit 31 leads from chamber A through a one way check valve 33 to the turbine elements which require a high pressure supply of liquid, including elements in the hydraulic governing system 32.

A low pressure volute 34 coacts with the low pressure impeller 14, within the chamber C of easing 8, and is the main pump taken on the 2,735,367 r W e equipped with packing seals 36 at all joints between it and-the lowpressure impeller 14. The volute 34.. has protruding flange portions 37 which terminally engage casing 9 in a manner keying volute 34 to the casing in exactly the same manner as previously described with respect to volute 24. Volute 34 discharges liquid from a passage 38 to the chamber C in casing 9. A conduit 39 conducts liquid fromthe chamber C through a one way check valve 42 tom oilcooler 41, and thence through a pressure reducing valve 43 and conduit 40 to turbine elements, such. as turbine bearing portions 44, requiring a low pressure supply ofliquid. Valve 43 serves to maintain the bearing liquid at a fixed even low pressure.

The chamber B in casing 9 constitutes a liquid sump from which impellers 13 and'14 are primed and otherwise supplied with oil. A conduit 46 leads into chamber B from an oilreservoir 47: this conduit includes a one way check valve 48. A bafiie plate 49 is disposed in chamber B to prevent-turbulence of the liquid in the sump as it is fed thereinto from conduit 46.

With the pump construction thus far described, the runner 12 and impellers 13 and 14 are fixed on shaft 7 for rotation therewith and move axially as a unit as the shaft 7 expands and contracts due to temperature changes.

The

volutes

24 and 34 are connected to the impellers 13- and 14 by

suitable seals

26 and 36, which afford rotation ofthe impellers-relative to the volutes.

When the turbine 6 heats up, shaft 7 expands axially, causing an axial displacement of the shoulder 19, which exerts a pressure on runner face 18 effective to force the impeller assembly including runner 12, impellers 13 and 14, and volutes 24 and 34, to move axially with the shaft 7. As the turbine 6 cools down and shaft 7 contracts, the coaction between the nut 22 and the runner face 21 forces the impeller assembly again to move axially with the shaft 7. Casing is designed with internal clearances sufficient to allow the impeller assembly to unobstructedly move longitudinally therewithin between limits determined by the hot and cold positions of the shaft 7.

As shown in Fig. l, conduit 31 leading from chamber A includes a branch 51 which extends into reservoir 47 and terminates in nozzle 52 positioned in an ejector pumping relation to the lower end of conduit 46. Conduit 39 leading from chamber C is provided with a branch 53 which extends into the reservoir 47 and is connected with the discharge of an auxiliary pump 54 operatively mounted in the reservoir 47. Branch 53 is provided with a one way check valve 56 and with a pressure reducing device 57, which is positioned in downstream relation from valve 56, considering pump 54 as being disposed in upstream relation to the valve. In addition, a short conduit 58 places branch 51, of conduit 31, in continuous communication with conduit 53 at a point between reducing valve 57 and check valve 56.

Pump 54 is driven by shaft 59 operatively connected with an electric motor 61 which is connected in turn with a suitable power source (not shown) through an automatic switch 62 and a manually actuated switch 63. Switch 62 is actuated by a diaphragm device 64 having a pressure connection with high pressure conduit 31 through a branch conduit 66. The operation of the diaphragm device 64 is such that switch 62 is held open so long as the pressure in branch conduit 66 is in excess of a predetermined amount.

To take care of overflow oil from turbine bearing portion 44, a conduit 67 extends between the bearing portion 44 and the reservoir 47, and conducts liquid from the bearing to the reservoir as it is forced out of the hearing by the inflow of liquid thereto from conduit 40.

With the parts positioned as shown in Fig. 1, it will be understood that the turbine 6 is operating normally and therefore the pump 8 is producing sufiicient liquid flow to lubricate the bearings and operate the hydraulic governing apparatus of the turbine. Under these conditions the pressure in branch conduit 66 which pressure is transmitted to the diaphragm device 64 is of a value elfectiveto maintain. switch 62in, an, openposition so .that.

motor 61 and pump 54 are not running. If for any reason the pressure in branch conduit 66 falls below a predetermined value, the diaphragm device 64 will act to close switch 62, starting motor 61 and pump 54. The discharge of pump 54 serves to supplement or replace the flow of pump 8 and thereby furnish liquid for lubrication and governor operation: as aforementioned.

The manually actuated switch-63 is always closed while the turbine 6.is running, but is opened during periods ofturbine shutdown since durmg such periods there is no need for pressure liquid to lubricate the turbine or operate its hydraulic governing-apparatus.

This improvedvliquid supply system provides an oil supply at a comparatively high pressure for operating hydraulic devices such as governing units, and provides also an oil supply at a much lower pressure for lubrication purposes. This is'all accomplished by means of the simplified system hereinbefore described which may include a unitarydouble volute pump coupled directly tothe shaft of the prime .moverwithout intermediate gearing. The effectiveness of the system is materially increased by the inclusion-and operation of a pump which isnot deleteriously affected by expansion or contraction of the prime mover shaft due-to changes in the temperature thereof. Such a pump includes features which are of more general application then that herein disclosed byway of example;

Accordingly it should be understood that the invention is not intended to be limited to the exact details of design, construction and/or combination described herein for purposes of illustration, as various changes andmodifications within the scope of the appended claims may be apparent to those skilled inthe art.

It is claimed and desired to secure by Letters Patent: 1. In a machine having a rotary shaft portion projecting therefrom, the combination comprising:

spaced volute elements operatively surrounding saidrunner elements; stationary casing means sealingly enclosing said pump means and having internal partitions coacting with said volute and runner elements to form a separate discharge chamber for each of said volute elements and a common inlet chamber intermediate said separate discharge chambers; said stationary casing having oppositely disposed wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion, means provided on each of said volute elements in slidable engagement with said slots'in said Wall portions nonrotatably supporting said volute elements for limited movement axially of said shaft; and seal means interposed between and operatively unitingsaid runner'and' volute elements for rotation of said runner relative to said volute elements.

2. In a machine having a rotary shaft portion projecting therefrom, the combination comprising: dual pump meansincluding a pair of runner elements fixed on said shaft for movement therewith and having outer portions spaced axially from each other and inner hubportions and separate liquid discharge chambers disposed on axially opposite sides of said inlet chamber, said stationary casing having oppositely disposed wall portions extending substantially parallel to said shaft and a longitudinallyextending slot in each wall portion, flange.

means provided oneach ofsaid volute elements in slidable engagement withsaid slot in said wall portions nondual pump means including a pair of runner elements fixed p. v. m,

rotatably supporting said volute elements for limited movement axially of said shaft; and seal means interposed between and operatively uniting said runner and volute elements for rotation of the former relative to the latter.

3. In a machine having a rotary shaft portion projecting therefrom, the combination comprising: dual pump means comprising a pair of pumps each including a runner element mounted on said shaft portion to turn and move axially therewith and a volute element peripherally surrounding said runner element; stationary casing means sealingly enclosing said pump means and having internal partitions coacting with said volute and runner elements to form a common inlet chamber and separate liquid discharge chambers, one for each of said volute elements, said stationary casing having oppositely disposed wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion, a pair of laterally opposed flanges provided on each of said volute elements in slidable engagement with said slots in said wall portions nonrotatably supporting said volute elements for limited movement axially of said shaft; and seal means interposed between and operatively uniting said runner and volute elements for rotation of the former relative to the latter.

4. In a machine having a rotary shaft portion projecting therefrom, a combination comprising: pump means including a runner element mounted on said shaft portion to turn and move axially therewith and a volute casing peripherally surrounding said runner element; a stationary outer casing sealingly enclosing said pump means, said stationary casing having oppositely disposed wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion; said pump means having oppositely disposed wall portions in juxtaposed relation to the wall portions of said stationary casing and flange means on the wall portions of said pump means in slidable keyed engagement with said slots in said wall portions for nonrotatably sup porting said volute casing for limited movement axially of said shaft.

5. In a machine having a rotary shaft portion projecting therefrom, a combination comprising: pump means including a runner element mounted on said shaft portion to turn and move axially therewith and a volute element peripherally surrounding said runner element; stationary casing means sealingly enclosing said pump means and having internal partition means coacting with said volute and runner elements to form an inlet chamber and a liquid discharge chamber for-said volute element, said stationary casing having oppositely disposed wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion; and volute support means provided on the periphery of said volute element in slidable engagement with said slots in said wall portions for nonrotatably supporting said volute element for limited movement axially of said shaft.

6. In a machine having a rotary shaft portion projecting therefrom, a combination comprising: pump means including a runner element mounted on said shaft portion to turn and move axially therewith and a volute element peripherally surrounding said runner element; stationary casing means sealingly enclosing said pump means and having internal partition means coacting with said volute and runner element to form an inlet chamber and a liquid discharge chamber for said volute element, said stationary casing having oppositely disposed wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion; and flange means provided on said volute element in slidable keyed engagement with said slots in said wall portions for non-rotatably supporting said volute element for limited movement axially of said shaft.

7. In a machine having a rotary shaft portion projecting therefrom, a combination comprising: pump means including a runner element mounted on said shaft portion to turn and move axially therewith and volute element peripherally surrounding said runner element; stationary casing means sealingly enclosing said pump means and having internal partition means coacting with said volute and runner element to form an inlet chamber and a liquid discharge chamber for said volute element, said stationary casing having oppositely disposed Wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion; and a pair of radially opposed flanges provided on the periphery of said volute element in slidable keyed engagement with said slots in said wall portions for nonrotatably supporting said volute element for limited movement axially of said shaft.

8. In a machine having a rotary shaft portion projecting therefrom, a combination comprising: pump means including a runner element mounted on said shaft portion to turn and move axially therewith and a volute element peripherally surrounding said runner element; stationary casing means sealingly enclosing said pump means and having internal partition means coacting with said volute and runner elements to form an inlet chamber and a liquid discharge chamber for said volute element, said stationary casing having oppositely disposed wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion; volute support means provided on the periphery of said volute element in slidable engagement with said slots in said Wall portions for nonrotatably supporting said volute element for limited movement axially of said shaft; and sealing means interposed between and operatively uniting said runner and volute element for rotation of the former relative to the latter.

9. In a machine having a rotary shaft portion projecting therefrom, a combination comprising: pump means including a runner element mounted on said shaft portion to turn and move axially therewith and a volute element peripherally surrounding said runner element; stationary casing means sealingly enclosing said pump means and having internal partition means coacting with said volute and runner element to form an inlet chamber and a liquid discharge chamber for said volute element, said stationary casing having oppositely disposed wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion; flange means provided on said volute element in slidable keyed engagement with said slots in said wall portions for nonrotatably supporting said volute element for limited movement axially of said shaft; and sealing means interposed between and operatively uniting said runner and volute element for rotation of the former relative to the latter.

10. In a machine having a rotary shaft portion projecting therefrom, a combination comprising: pump means including a runner element mounted on said shaft portion to turn and move axially therewith and volute element peripherally surrounding said runner element; stationary casing means sealingly enclosing said pump means and having internal partition means coacting with said volute and runner element to form an inlet chamher and a liquid discharge chamber for said volute element, said stationary casing having oppositely disposed Wall portions extending substantially parallel to said shaft and a longitudinally extending slot in each wall portion; a pair of radially opposed flanges provided on the periphery of said volute element in slidable keyed arrangement with said slots in said wall portions for nonrotatably supporting said volute element for limited movement axially of said shaft; and sealing means interposed between and operatively uniting said runner and volute element for rotation of the former relative to the latter.

(References on following page) ReferencesCited in the file of this patent UNITED STATES PATENTS Guy Nov. 23, 1909 Ross --Feb. 11, 1919 Schmidt Feb. 15, 1927 Ames Apr. 5, 1927 Alsenstein Oct. 15, 1935 8 Sheppard May 4, 1948 Conery Apr. 12, 1949 Conery --July 15, 1952 FOREIGN PATENTS Great Britain Feb. 10, 1949 Great Britain Mar. 14, 1949