On one hand, altering the geometry of certain internal components of a pump increases pump efficiency and reduces noise, but negatively affects the self-priming capability. On the other hand, altering the geometry of other internal components of a pump improves the self-priming capability but degrades overall pump performance and increases noise. The present invention combines these changes to the internal components of a pump. As a result, the advantages of the two types of modifications are combined, resulting in a self-priming, centrifugal pump having improved efficiency and reduced noise in which the self-priming capability is maintained.
Altering the geometry of the inventive pump result in drastic improvements to overall performance. For example, modifications to the inventive 6″ pump resulted in a 10% increase in efficiency and a 4.9 DbA reduction in the noise level over a conventional pump at the same speeds (see Table 1). The inventive 6″ pump even showed improvements at a speed higher than that of a conventional pump, as shown in Table 1. At the same time, the self-priming capability is maintained as shown by the increase in lift of 1-2 ft., depending on the speed of the pump (see Table 2). Similar improvements can be shown for the inventive 3″ and 4″ pumps.
Referring now to
In some aspects of the invention, impeller 401 comprises gray iron, ductile iron, hard iron, CF8M stainless-steel, or CD4MCu. In one aspect, the impeller 401 comprises an impeller such as described in the patent application titled “Improved Impeller and Wear Plate”, assigned to the Gorman-Rupp Company, and filed on Oct. 31, 2003 as U.S. patent application Ser. No. 10/697,162, and which is hereby incorporated by reference in its entirety. The rotating assembly 400 is attached to a corresponding surface of the volute housing 101 using one or more mechanical fasteners, such as a plurality of bolts or screws. O-rings 417, 416 are provided to both seal the connection between the rotating assembly 400 and such corresponding surface of the centrifugal volute housing 101, as well as to facilitate external clearance adjustments.
The removable back cover and wear plate assembly 300, which is also offered by the Gorman-Rupp Company, is shown to include a back cover 328 having a handle 336, locking collar 329, adjustment screw 331, hand nut 333, and hex head capscrew 332. The removable back cover and wear plate assembly 300 is described in the patent application titled “Centrifugal Pump Having Adjustable Cleanout Assembly”, assigned to the Gorman-Rupp Company, and filed on Sep. 16, 2002 as U.S. patent application Ser. No. 10/221,825, and which is hereby incorporated by reference in its entirety. In one aspect, shown in
Support posts 316a-d are provided to dispose the wear plate 323 at a predetermined location within the volute housing 101. In the illustrated example, the support posts 316a-d are ribs and the position of the wear plate 323 may be adjusted by adjusting a position of the back cover 328 relative to volute housing 101. In other aspects, however, support posts 316a-d may be adjustable to permit positioning adjustment by variation of an adjustable length of the support posts. Suction flange 338 and suction gasket 339 are connected to volute housing 101 by mechanical fasteners to provide a suction.
Flap valve or check valve 113 is optionally disposed on an inside of the suction and affixed at an upper end to the centrifugal volute housing 101 by flap valve cover 114. Flap valve cover 114 is attached with mechanical fasteners that permit flap valve 113 to be accessed without the need for special tools.
In one aspect of the invention, shown in
Referring now to
5.39 in.2(volute scroll throat area)/13.39 in.2(impeller REA)=0.40.
In contrast, the inventive 3″ pump has the following relevant characteristics and ultimate ratio:
8.61 in.2(volute scroll throat area)/14.448 in.2(impeller REA)=0.60.
The range of volute scroll throat area 502a includes about 7.75 in.2. The range of impeller REA 401a includes about 13.00 in.2 to about 15.89 in.2. Increasing the volute scroll throat area to impeller REA of the 3″ pump helps improve efficiency and reduces noise, as shown by the test results below in Table 1. An inventive 6″ pump is 10 percentage points more efficient than a conventional pump and 4.9 DbA quieter at the same speeds.
The testing details are as follows.
For the pumps used, “Tx” denotes a conventional pump such as a Gorman-Rupp T-Series pump, with “x” corresponding to the discharge size. For example, T6 denotes the T-Series 6” pump. “Vx” denotes an inventive pump such as a Gorman-Rupp V-Series pump, with “x” denoting the discharge size.
Similarly, for the conventional, self-priming 4″ pump:
8.61 in.2(throat area)/21.21 in.2(impeller REA)=0.41.
In contrast, the inventive 4″ pump has the following relevant characteristics ultimate ratio:
14.490 in.2(volute scroll throat area)/18.49 in.2(impeller REA)=0.78.
The range for volute scroll throat area 502a includes about 13.04 in.2 to about 15.94. The range for impeller REA 401a includes about 16.64 in.2 to about 20.33 in2.
Similarly, for the conventional, self-priming 6″ pump:
13.61 in.2(volute scroll throat area)/19.33 in.2(impeller REA)=0.70.
In contrast, the inventive 6″ pump has the following relevant characteristics and ultimate ratio:
23.68 in.2(throat area)/23.520 in.2(impeller REA)=1.01.
The range for volute scroll throat area 502a includes about 21.32 in.2 to about 26.01 in.2. The range for the impeller REA includes about 21.17 in2 to about 25.87 in.2.
Increasing the volute scroll throat area to impeller REA ratio increases pump performance and reduces noise, as shown by test results in Table 1. For example, the conventional 6″ self-priming, centrifugal pump is 61.5% efficient and generates 83.9 DbA of noise at a speed of 1650 rpm. In contrast, the 6″ pump of this embodiment of the present invention is 71.5% efficient and generates 79.0 DbA of noise at the same speed. In fact, the 6″ pump of this embodiment of the present invention is more efficient and quieter at its maximum speed of 2000 rpm than the same 6″ version of a conventional self-priming, centrifugal pump operating at a lesser speed.
Ratios of volute scroll throat area to impeller REA include a range of about 0.54 to about 1.11.
The volume of volute scroll 502 can also be enlarged by increasing the width of the scroll without enlarging volute scroll throat area 502a, or other dimensions can also be increased. The ratio of the volume of volute scroll 502 to the cross-sectional area of the discharge comprises a range of about 35.79 to 73.60.
Tests results indicate that the enlarged volume of volute scroll 502 contributes to overall performance of pump 100 while reducing noise, as is illustrated by Table 1.
For example, for a conventional 3″ self-priming, centrifugal pump:
9.07 in.(cutwater diameter)/8.75 in.(impeller diameter)=1.04.
In contrast, an inventive 3″ pump has the following relevant characteristics and ultimate ratio:
10.06 in.(cutwater diameter)/9.00 in.(impeller diameter)=1.12.
Distance d between cutwater member 502b and impeller OD 401b includes a range of about “0.48 to about 0.58”.
Similarly, for a conventional, self-priming 4″ pump:
10.07 in.(cutwater diameter)/9.75 in.(impeller diameter)=1.03.
In contrast, an inventive 4″ pump has the following relevant characteristics and ultimate ratio:
11.100 in.(cutwater diameter)/9.750 in.(impeller diameter)=1.140.
Distance d between cutwater member 502b and impeller OD 401b includes a range of about 0.61″ to about 0.74″.
For a conventional, self-priming 6″ pump:
13.005 in.(cutwater diameter)/12.375 in.(impeller diameter)=1.01.
In contrast, an inventive 6″ pump has the following relevant characteristics and ultimate ratio:
14.060 in.(cutwater diameter)/12.375 in.(impeller diameter)=1.14.
Distance d between cutwater member 502b and impeller OD 401b includes a range of about 0.76″ to about 0.93″.
The ratio of cutwater diameter to impeller OD includes a range of about 1.01 to about 1.25.
Resulting improvements in the self-priming capability of pump 100 are demonstrated by the tests results shown in Table 2, below.
For a conventional 3″ self-priming, centrifugal pump:
1842.91 in.3(discharge hopper volume)/729.00 in.3(suction hopper volume)=2.53.
In contrast, an inventive 3″ pump has the following relevant characteristics and ultimate ratio:
2772.48 in.3(discharge hopper volume)/1613.67 in.3(suction hopper volume)=1.72.
The volume of discharge hopper 504 includes a range of about 2495.23 in.3 to about 3049.73 in.3.
For a conventional 4″ self-priming, centrifugal pump:
2631.69 in.3(discharge hopper volume)/1295.99 in.3(suction hopper volume)=2.03.
In contrast, an inventive 4″ pump has the following relevant characteristics and ultimate ratio:
2693.06 in.3(discharge hopper volume)/2021.60 in.3(suction hopper volume)=1.33
The volume of discharge hopper 504 includes a range of about 2423.75 in.3 to about 2962.37 in.3.
For a conventional 6″ self-priming, centrifugal pump:
3194.85 in.3(discharge hopper volume)/2276.11 in.3(suction hopper volume)=1.40.
In contrast, an inventive 6″ pump has the following relevant characteristics and ultimate ratio:
3164.17 in.3(discharge hopper volume)/3503.51 in.3(suction hopper volume)=0.923.
The volume of discharge hopper 504 includes a range of about 2847.75 in.3 to about 3480.50 in.3.
The ratio of the volume of discharge hopper 504 to the volume of suction hopper 503 includes a range of about 1.89 to 0.84.
For example, for a conventional, self-priming pump at a speed of 1650 rpm having a suction hopper of 2276.11 in.3, the lift is 21 ft. For an inventive pump at the same speed but with a suction hopper of 3503.51 in.3, the lift is 23 ft. Increased lift indicates improved self-priming.
Thus, it can be seen that as the ratio of discharge hopper volume to suction hopper volume decreases, the self-priming function of the inventive pump increases, as seen in Table 2.
For an inventive 3″ pump:
12.57 in.2(4″ suction area)/7.07 in.2(3″ discharge area)=1.78.
For an inventive 4″ pump:
28.27 in.2(6″ suction area)/12.57 in.2(4″ discharge area)=2.25.
For an inventive 6″ pump:
50.27 in.2(8″ suction area)/28.27 in.2(6″ discharge area)=1.77.
The cross-sectional areas of discharge 530 of an inventive 3″, 4″, and 6″ pump are about 7.07 in.2, 12.57 in.2, and 28.27 in.2, respectively.
The ratio of the cross-sectional area of discharge 530 to the cross-sectional area of suction 520 includes a range of about 1.59 to about 2.48.
Increasing the size of suction 520 increases the NPSHa of the system, increases flow and increases operating range. The larger diameter of suction 520 also helps reduce noise, as shown in Table 1.
In addition to the ability to adjust the length of support posts 316a-d previously mentioned above, the location size, or shape may be altered to improve flow characteristics.
For example, back cover and wear plate assembly 300 includes support posts 316a-d. Support posts 316a-d, shown in
To enhance the self-cleaning capability of pump 100 in this embodiment of the present invention, support posts 316a-b are relocated to positions farther apart and farther away from the vertical center line of volute 502, best shown in
In addition to relocating support posts 316a-d, the self-cleaning function of pump 100 is improved by adding notches 323a and divots 328a to wear plate 323 and back cover 328, respectively.
In a conventional arrangement, the wear plate and back cover are smooth, i.e., are free of notches, divots, or other indentations. However, debris contained in the pumped liquid tends to collect on the surface of the inner diameter of the wear plate and back cover. Collected debris builds up as the pump is operated, flow is reduced, and eventually the pump becomes inoperative.
In this embodiment of the present invention, notches 323a are added to wear plate 323, as shown in
Furthermore, divots 328a are added to the inner circumference of back cover 328. The location of divots 328a corresponds to the location of notches 323a. As liquid flows through pump 100, it is channeled through divots 328a and assists in removing any solids that may have collected on notches 323a. Divots 328a are cone-shaped, as shown in
The changes made to wear plate and back cover assembly 300 assist in the self-cleaning capability of pump 100 as well as increase performance by resisting clogging and therefore maintaining maximum flow.
In further embodiments, other conventional universal sealing arrangements are provided in place of the removable back cover and wear plate assembly 300.
The present invention can be practiced by employing conventional materials, methodology and equipment. Accordingly, the details of such materials, equipment and methodology are not set forth herein in detail. In the previous descriptions, numerous specific details are set forth, such as specific materials, structures, chemicals, processes, etc., in order to provide a thorough understanding of the present invention. However, it should be recognized that the present invention can be practiced without resorting to the details specifically set forth. In other instances, well known processing structures have not been described in detail, in order not to unnecessarily obscure the present invention.
Only an exemplary embodiment of the present invention and but a few examples of its versatility are shown and described in the present disclosure. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein.
This application claims the benefit of U.S. Provisional Application No. 60/846,093, filed Sep. 21, 2006, which is hereby incorporated herein by reference in its entirety.
Number | Date | Country | |
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60846093 | Sep 2006 | US |