Multi-piston engine, such as a pump or compressor, with improved vibrational behaviour
First Claim
1. A multi-piston engine, such as, for example, a pump or a compressor, which comprises drive shaft (1);
- a number of cylinders (2a, 2b, 2c);
a number of pistons (3a, 3b, 3c) selectively driven by the alternating motion of the drive shaft and respectively housed in cylinders (2a, 2b, 2c) in order to delimit, for a fluid put in motion by the engine, a corresponding number of chambers (4a, 4b, 4c) with variable volume, each of which presents a predetermined maximum volume (Va, Vb, Vc) to the fluid and has low pressure intake (40a, 40b, 40c) and high-pressure outlet (41a, 41b, 41c); and
a number of delivery channels (5a, 5b, 5c) connecting the high pressure outlets of the respective chambers to delivery outlet (6) of the engine, each delivery channel (5a, 5b, 5c) having a predetermined cross section (Sa, Sb, Sc) and a predetermined length (La, Lb, Lc), the movement of each piston (3a, 3b, 3c) bringing about a vibrational excitation of the engine, of determined fundamental frequency (Fa, Fb, Fc), and each chamber (4a, 4b, 4c), in association with piston (3a, 3b, 3c) which delimits it and with delivery channel (5a, 5b, 5c) which connects it to delivery outlet (6), forming a corresponding module (3a, 4a, 5a;
3b, 4b, 5b;
3c, 4c, 5c) of the engine, characterized by the fact that it comprises at least a first spectral spreading means associated with a first pair of modules (3a, 4a, 5a;
3b, 4b, 5b) including a first pair of pistons (3a, 3b), this first spectral spreading means being suitable for introducing, between the fundamental frequencies (Fa, Fb) of the vibrational excitations resulting from the respective movements of pistons (3a, 3b) of this first pair, a frequency shift (Δ
Fab) equal to at most 10% of the fundamental frequency (Fa) of the vibrational excitation resulting from the movement of either (3a) of the pistons of this first pair (3a, 3b).
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Abstract
The invention relates to a piston engine which is essentially comprised of an engine shaft (1) and a set of modules, each of which comprises a cylinder (2a, 2b) and a piston (3a, 3b) powered by the engine shaft in the cylinder, each module resulting in vibratory excitation of the engine at a determined fundamental frequency (Fa, Fb). Rather than introducing phase differences between the various vibratory excitations, as is the case in prior art, the invention introduces a frequency offset (ΔFab) between the fundamental frequencies (Fa, Fb) thereof in order to avoid a high-amplitude vibration at a common excitation frequency (F), arising from the spectral spread thus obtained.
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Citations
14 Claims
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1. A multi-piston engine, such as, for example, a pump or a compressor, which comprises drive shaft (1);
- a number of cylinders (2a, 2b, 2c);
a number of pistons (3a, 3b, 3c) selectively driven by the alternating motion of the drive shaft and respectively housed in cylinders (2a, 2b, 2c) in order to delimit, for a fluid put in motion by the engine, a corresponding number of chambers (4a, 4b, 4c) with variable volume, each of which presents a predetermined maximum volume (Va, Vb, Vc) to the fluid and has low pressure intake (40a, 40b, 40c) and high-pressure outlet (41a, 41b, 41c); and
a number of delivery channels (5a, 5b, 5c) connecting the high pressure outlets of the respective chambers to delivery outlet (6) of the engine, each delivery channel (5a, 5b, 5c) having a predetermined cross section (Sa, Sb, Sc) and a predetermined length (La, Lb, Lc), the movement of each piston (3a, 3b, 3c) bringing about a vibrational excitation of the engine, of determined fundamental frequency (Fa, Fb, Fc), and each chamber (4a, 4b, 4c), in association with piston (3a, 3b, 3c) which delimits it and with delivery channel (5a, 5b, 5c) which connects it to delivery outlet (6), forming a corresponding module (3a, 4a, 5a;
3b, 4b, 5b;
3c, 4c, 5c) of the engine, characterized by the fact that it comprises at least a first spectral spreading means associated with a first pair of modules (3a, 4a, 5a;
3b, 4b, 5b) including a first pair of pistons (3a, 3b), this first spectral spreading means being suitable for introducing, between the fundamental frequencies (Fa, Fb) of the vibrational excitations resulting from the respective movements of pistons (3a, 3b) of this first pair, a frequency shift (Δ
Fab) equal to at most 10% of the fundamental frequency (Fa) of the vibrational excitation resulting from the movement of either (3a) of the pistons of this first pair (3a, 3b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- a number of cylinders (2a, 2b, 2c);
Specification