US2009290997A1PendingUtilityA1
Reduced flow pulsations in a tandem floating cup pump with an odd number of pistons
Est. expiryMay 23, 2028(~1.9 yrs left)· nominal 20-yr term from priority
F04B 1/22
50
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Claims
Abstract
A method for reducing the flow pulsations in a tandem floating cup pump having an odd number of pistons includes determining a low noise net index angle that produces reduced flow pulsations relative to those produced when the net index angle is either zero or half the separation angle and offsetting a first rotating group relative to a second rotating group by the low noise net index angle. The net index angle is the sum of a piston index angle and the port plate index angle. The piston index angle is the angle between a piston from a first rotating group and an adjacent piston from a second rotating group whereas the port plate index angle is the angle by which a first port plate is offset relative to a second port plate.
Claims
exact text as granted — not AI-modified1 . A method for reducing flow pulsations in a tandem floating cup pump having an odd number of pistons in each of a first and second rotating group, each piston on each rotating group spaced equally apart from an adjacent piston by a separation angle, comprising the steps of:
determining a low noise net index angle that corresponds to reduced flow pulsations with respect to the flow pulsations produced at a net index angle of zero and the flow pulsations produced at a net index angle of half the separation angle; setting a net index angle between a top dead center orientation of the first rotating group relative to a top dead center orientation of the second rotating group to the low noise net index angle.
2 . The method of reducing flow pulsations of claim 1 wherein the step of setting the net index angle to the low noise net index angle is performed by offsetting a first port plate relative to a second port plate by the low noise net index angle.
3 . The method of reducing flow pulsations of claim 1 wherein the step of setting the net index angle to the low noise net index angle is performed by offsetting the first rotating group relative to the second rotating group by the low noise net index angle via a rotor.
4 . The method of reducing flow pulsations of claim 1 wherein the determining step includes the steps of:
selecting the number of pistons on each rotating group; determining a net index angle by choosing an angle greater than one of a minimum angle of a first range and a minimum angle of a second range, but less than one of a maximum angle of a first range and a maximum angle of a second range, respectively, that corresponds to the selected number of pistons in each rotating group, using the following table:
Net index angle (in Deg)
First Range
Second Range
N
Minimum
Maximum
Minimum
Maximum
5
8.64
27.36
44.64
63.36
7
6.17
19.54
31.89
45.26
9
4.80
15.20
24.80
35.20
11
3.93
12.44
20.29
28.80
13
3.32
10.52
17.17
24.37
15
2.88
9.12
14.88
21.12
17
2.54
8.05
13.13
18.64
19
2.27
7.20
11.75
16.67
21
2.06
6.51
10.63
15.09
23
1.88
5.95
9.70
13.77
25
1.73
5.47
8.93
12.67
27
1.60
5.07
8.27
11.73
29
1.49
4.72
7.70
10.92
31
1.39
4.41
7.20
10.22
33
1.31
4.15
6.76
9.60
35
1.23
3.91
6.38
9.05
wherein N represents the number of pistons in each rotating group.
5 . The method of reducing flow pulsations of claim 4 wherein the determining step includes the steps of:
selecting the number of pistons on each rotating group; determining a net index angle by choosing an angle about equal to one of a low best angle and a high best angle, that corresponds to the selected number of pistons in each rotating group, using the following table:
Best Net Index
Angle
(in degrees)
N
Low Best
High Best
5
18
54
7
13
39
9
10
30
11
8.2
25
13
6.9
21
15
6.0
18
17
5.3
16
19
4.7
14
21
4.3
13
23
3.9
12
25
3.6
11
27
3.3
10
29
3.1
9.3
31
2.9
8.7
33
2.7
8.2
35
2.6
7.7
wherein N represents the number of pistons in each rotating group.
6 . A floating cup pump, comprising:
a rotor, a first barrel plate and a second barrel plate, attached to a shaft; a first rotating group comprising a first set of an odd number of floating cups, each floating cup swivelly attached to the first barrel plate, a first set of an odd number of pistons, each piston being equally spaced apart from an adjacent piston by a separation angle and each piston having a first end and a second end, the first end of each piston attached to the rotor, the second end of each piston received by a respective one of the first set of floating cups; a second rotating group comprising a second set of the odd number of floating cups, each floating cup swivelly attached to the second barrel plate, a second set of pistons, having a same number of pistons as the first rotating group, each piston being equally spaced apart from an adjacent piston by the separation angle and each piston having a first end and a second end, the first end of each piston attached to the rotor, the second end of each piston received in a respective one of the second set of floating cups; the first rotating group and the second rotating group having a first relative orientation, the first relative orientation defining a piston index angle; a first port plate adjacent the first barrel plate defining a bottom dead center position of the first rotating group; a second port plate adjacent the second barrel plate defining a bottom dead center position of the second rotating group; the bottom dead center of the first rotating group and the bottom dead center of the second rotating group having a second relative orientation, the second relative orientation defining a port plate index angle; a low noise net index angle being the sum of the piston index angle and the port plate index angle, wherein the low noise net index angle is different from zero and half of the separation angle.
7 . The floating cup pump of claim 6 wherein the low noise net index angle depends on the number of pistons in each rotating group.
8 . The floating cup pump of claim 6 wherein the port plate index angle is the low noise net index angle, and the piston index angle is zero.
9 . The floating cup pump of claim 6 wherein the piston index angle is the low noise net index angle, and the port plate index angle is zero.
10 . The floating cup pump of claim 6 wherein each rotating group has eleven pistons and the low noise net index angle is about equal to one of 8 degrees and 25 degrees.
11 . The floating cup pump of claim 6 wherein the low noise net index angle for an odd number of pistons ranging from 5 to 35 pistons in each rotating group is one of the greater than the minimum of the first range and less than the maximum of the first range, and greater than the minimum of the second range and less than the maximum of the second range, respectively, with respect to the following table:
Net index angle (in Deg)
First Range
Second Range
N
Minimum
Maximum
Minimum
Maximum
5
8.64
27.36
44.64
63.36
7
6.17
19.54
31.89
45.26
9
4.80
15.20
24.80
35.20
11
3.93
12.44
20.29
28.80
13
3.32
10.52
17.17
24.37
15
2.88
9.12
14.88
21.12
17
2.54
8.05
13.13
18.64
19
2.27
7.20
11.75
16.67
21
2.06
6.51
10.63
15.09
23
1.88
5.95
9.70
13.77
25
1.73
5.47
8.93
12.67
27
1.60
5.07
8.27
11.73
29
1.49
4.72
7.70
10.92
31
1.39
4.41
7.20
10.22
33
1.31
4.15
6.76
9.60
35
1.23
3.91
6.38
9.05
wherein N represents the number of pistons in each rotating group.
12 . The floating cup pump of claim 6 wherein the low noise net index angle for an odd number of pistons ranging from 5 to 35 pistons in each rotating group is about equal to one of a low best and a high best, with respect to the following table:
Best Net Index
Angle
(in degrees)
N
Low Best
High Best
5
18
54
7
13
39
9
10
30
11
8.2
25
13
6.9
21
15
6.0
18
17
5.3
16
19
4.7
14
21
4.3
13
23
3.9
12
25
3.6
11
27
3.3
10
29
3.1
9.3
31
2.9
8.7
33
2.7
8.2
35
2.6
7.7
wherein N represents the number of pistons in each rotating group.
13 . A floating cup pump, comprising:
a rotor, a first barrel plate and a second barrel plate, attached to a shaft; a first rotating group comprising a first set of an odd number of floating cups, each floating cup swivelly attached to the first barrel plate, a first set of an odd number of pistons, each piston being equally spaced apart from an adjacent piston by a separation angle and each piston having a first end and a second end, the first end of each piston attached to the rotor, the second end of each piston received by a respective one of the first set of floating cups; a second rotating group comprising a second set of the odd number of floating cups, each floating cup swivelly attached to the second barrel plate, a second set of pistons, having a same number of pistons as the first rotating group, each piston being equally spaced apart from an adjacent piston by the separation angle and each piston having a first end and a second end, the first end of each piston attached to the rotor, the second end of each piston received in a respective one of the second set of floating cups; the first rotating group and the second rotating group having a first relative orientation, the first relative orientation defining a piston index angle; a first port plate adjacent the first barrel plate defining a bottom dead center position of the first rotating group; a second port plate adjacent the second barrel plate defining a bottom dead center position of the second rotating group; the bottom dead center of the first rotating group and the bottom dead center of the second rotating group having a second relative orientation, the second relative orientation defining a port plate index angle; a net index angle being the sum of the piston index angle and the port plate index angle; and means, including setting the net index angle to a low noise net index angle different from zero and half the separation angle, for reducing noise due to flow pulsations.
14 . The floating cup pump of claim 13 wherein the means for reducing noise due to flow pulsations reduces the noise to lower than the noise produced when the net index angle is zero.
15 . The floating cup pump of claim 13 wherein the means for reducing noise due to flow pulsations reduces the noise to lower than the noise produced when the net index angle is half the separation angle.
16 . The floating cup pump of claim 13 wherein the port plate index angle is the low noise net index angle, and the piston index angle is zero.
17 . The floating cup pump of claim 13 wherein the piston index angle is the low noise net index angle, and the port plate index angle is zero.
18 . The floating cup pump of claim 13 wherein each rotating group has eleven pistons and the net index angle is about equal to one of 8 degrees and 25 degrees.
19 . The floating cup pump of claim 13 wherein the low noise net index angle for an odd number of pistons ranging from 5 to 35 pistons in each rotating group is one of the greater than the minimum of the first range and less than the maximum of the first range, and greater than the minimum of the second range and less than the maximum of the second range, respectively, with respect to the following table:
Net index angle (in Deg)
First Range
Second Range
N
Minimum
Maximum
Minimum
Maximum
5
8.64
27.36
44.64
63.36
7
6.17
19.54
31.89
45.26
9
4.80
15.20
24.80
35.20
11
3.93
12.44
20.29
28.80
13
3.32
10.52
17.17
24.37
15
2.88
9.12
14.88
21.12
17
2.54
8.05
13.13
18.64
19
2.27
7.20
11.75
16.67
21
2.06
6.51
10.63
15.09
23
1.88
5.95
9.70
13.77
25
1.73
5.47
8.93
12.67
27
1.60
5.07
8.27
11.73
29
1.49
4.72
7.70
10.92
31
1.39
4.41
7.20
10.22
33
1.31
4.15
6.76
9.60
35
1.23
3.91
6.38
9.05
wherein N represents the number of pistons in each rotating group.
20 . The floating cup pump of claim 13 wherein the low noise net index angle for an odd number of pistons ranging from 5 to 35 pistons in each rotating group is about equal to one of a low best and a high best, with respect to the following table:
Best Net Index
Angle
(in degrees)
N
Low Best
High Best
5
18
54
7
13
39
9
10
30
11
8.2
25
13
6.9
21
15
6.0
18
17
5.3
16
19
4.7
14
21
4.3
13
23
3.9
12
25
3.6
11
27
3.3
10
29
3.1
9.3
31
2.9
8.7
33
2.7
8.2
35
2.6
7.7
wherein N represents the number of pistons in each rotating group.Cited by (0)
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