PUMP

FIELD OF THE INVENTION

The invention relates to a pump as defined in the preamble of claim 1. The pump in accordance with the invention has been developed specifically for pumping fluids with high viscosity, such as heavy fuel oil and the like, for example in conjunction of different oil spill prevention and response operations.

BACKGROUND OF THE INVENTION

¹ The prior art in the field of the invention has been described in patent specifications US2058230, US2716861, US3182600, US3726616 and US4470781. The known pumps comprise a spiral rotor and a seal disk which rotates in contact with the surface of the rotor with the shapes thereof adapted to rotate in engagement with the shapes of the spiral .

Although the known pumps work appropriately, they have many significant disadvantages. The pumps are large and heavily constructed. Moreover, their pumping capacity is relatively modest despite their heavy power consumption. Therefore their use is inconvenient for example in different skimmers and other floating oil collecting devices. Due to their complex construction and large size, they are also disadvantageous as to their production and operation costs.

OBJECTIVE OF THE INVENTION The objective of the invention is to eliminate the drawbacks of the prior art referred to above. One specific objective of the invention is to disclose a novel pump construction which allows an effective pumping and displacing of fluids with high viscosity,

and yet is simple in construction, light and compact with low power-consumption.

SUMMARY OF THE INVENTION The pump in accordance with the invention comprises a pump chamber, a suction duct that leads into the pump chamber, a discharge duct that leads out of the pump chamber, and in the pump chamber a rotor having a shaft in which the cross-sectional profile of the outer surface is a circular arch, and a spiral flange supported on the shaft. The pump further comprises a disk, a so-called seal disk, which is parallel to the shaft of the rotor and follows the shape of the circular outer surface of the shaft, the disk be- ing arranged to rotate about its center in a narrow disk chamber which opens into the pump chamber, and being provided with a slot into which the spiral flange is able to slide during rotation of the spiral flange and the disk. In accordance with the invention, the inner surface of the pump chamber is spherical, and the periphery of the spiral flange corresponds by shape to the spherical surface, so that it rests tightly against it. Further in accordance with the invention, the spiral flange extends in one full revolu- tion about the shaft, i.e. about 360°, and the seal disk comprises four radial slots arranged at intervals of 90°, through which slots the spiral flange will be able to slide.

Preferably the spiral flange makes around the shaft a revolution of slightly over 360°, so that, during operation of the pump and rotation of the rotor and the seal disk, as the spiral flange leaves one slot of the seal disk at one end of the spiral flange, the other end of the spiral flange will already be sliding into the outset of the next slot. Thus, the spiral flange will always be positioned at some part

in a slot of the seal disk, ensuring an accurate and precise operation of the spiral flange and the seal disk relative to each other in each of their positions relative to each other. Preferably, the outer surface of the spiral flange which rests against the spherical surface of the pump chamber is arched both in longitudinal direction and in transverse direction, corresponding in its arching to the spherical surface of the pump chamber, and, furthermore, it is preferably narrowest in the middle of the spiral, increasing in width from there on in both directions.

The spiral flange may be a plate which has both lengthwise and widthwise the same diameter from one end to the other, but the diameter may also vary, such that the spiral flange may be thinner at the outer edge, with the diameter increasing towards the shaft of the rotor. Preferably, the spiral flange is perpendicular to its axis in the middle of the spiral, and, from the middle, arranged to evenly incline inwards in both directions towards both ends, starting from the middle of the spiral. In this manner, the spiral flange will be symmetrical relative to its center. At the same time, both ends of the spiral flange are preferably positioned at an angle of about 45° relative to its axis.

The shape of the radial slot in the disk, the seal disk, corresponds to the cross-sectional shape of the spiral flange at its widest point. Thus, when the full width of the spiral flange is placed in a slot of the disk in the middle of the spiral, the spiral will be tightly positioned in the slot, without formation of any leaks between the disk and the spiral that would risk the tightness of the pump. At positions other than the middle, the spiral flange will extend to a portion of the length of the slot only, however

it extends entirely to the portion of the slot that is inside the pump chamber, while the rest of the slot will be inside the disk chamber adapted for the disk. Thus, the pump construction will remain sealed at all rotation angles of the rotor.

Preferably, the shaft of the rotor extends out of the pump chamber on the side of the discharge duct. In that case, the suction duct and the flow from the suction duct into the pump chamber are substan- tially parallel to the shaft of the rotor. Thus, the suction duct can be arranged to form a relatively large, for example circular, duct that surrounds the shaft of the rotor. In this manner, a flow resistance which is as low as possible can be provided on the suction side of the pump. It is also possible that the suction duct comprises an adjustment of its flow cross-sectional area for enabling alteration of the cross-sectional area of the suction duct according to varying suction conditions and properties, mostly vis- cosity, of the suction fluid.

The pump in accordance with the invention provides considerable advantages compared to prior art. In the invention, the compact and light pump provides effective suction at low rotation speeds, and, above all, the volume flow provided by the pump is very high relative to the size of the pump.

LIST OF FIGURES

In the following section, the invention will be described in detail with reference to the accompanying drawings, in which

Fig. Ia shows a sectional view of one pump chamber of the pump in accordance with the invention,

Fig. Ib represents the disk which rotates in the disk chamber,

Fig. 2a represents the pump chamber provided with the shaft of the rotor,

Fig. 2b represents a sectional view of the pump as seen from the top, Fig. 3a and 3b represent the pump in two different operating positions,

Fig. 4a and 4b show the spiral rotor from the side and from the top and

Fig. 5 represents the shaft of the rotor and the disk connected thereto.

DETAILED DESCRIPTION OF THE INVENTION

As shown in Fig. Ia, the pump in accordance with the invention comprises a spherical pump chamber 1, into which a suction duct 2 and a discharge duct 3 open from opposite directions. Also opening into the pump chamber is a narrow and circular, disk-like disk chamber 8, with a disk 7 in accordance with Fig. Ib, a so-called seal disk, being arranged to rotate therein. The seal disk comprises four radial slots 9 at even intervals, i.e. at intervals of 90°, so that the disk 7 is divided into four equal sectors S.

In accordance with Fig. 2a, placed in the pump chamber 1 is the shaft 5 of the rotor 4 of the pump, the shaft having, in longitudinal cross-section, the shape of a circular arch, such that it is thinnest in the center of the pump chamber, increasing in diameter and arching evenly towards the suction duct 2 and the discharge duct 3. Thus, the outer edge of the disk 7 placed in the disk chamber 8 rests tightly against the corresponding circular surface 12 of the shaft 5.

Fig. 2a also shows an extension or spiral 11 placed at the outer end of the shaft 5, i.e. at the suction duct 2, for increasing the efficiency of the

pump fluid flow into the pump chamber 1 via the suction duct 2. Fig. 2a shows as well the bearing 13 and the bolts 14 of the shaft 5 which are used for mounting the motor 15, which rotates the shaft, to the pump.

Fig. 2b shows in more detail the circular construction of the suction duct 2 around the shaft 5, and the tubular construction of the discharge duct 3 which guides the pumped fluid past the shaft 5 and obliquely away from the shaft and from the vicinity of the seal disk 7.

Fig. 4a and 4b show the above-described shaft 5 of the pump, with a spiral flange 6, which performs the actual pumping operation, attached thereto. The outer edge 10 of the spiral flange 6 is placed on the spherical surface corresponding to the inner surface of the pump chamber, so that the spiral flange rests tightly against the spherical surface of the pump chamber along the full length and width of its edge. The spiral flange 6 is, in the longitudinal direction of the shaft 5, widest in the middle, and, at the same time, perpendicular to the shaft. From there on, in both directions, the flange evenly narrows and inclines inwards, i.e. it is substantially perpendicular to the inner surface of the pump chamber 1. Furthermore, the width of the outer edge 10 of the spiral flange increases towards both ends. In one embodiment of the invention, the lower or outer edge 16 of the spiral flange 6 on the side of the suction opening 2 is arranged to be sharp, so that it efficiently cuts and chops all elongated impurities, such as water plants, which are drawn for the pump chamber due to suction, and would possibly block the pump.

As shown in Fig. 4a, the spiral flange 6 makes around the shaft 5 a revolution of slightly over 360°, i.e. seen in the direction of the shaft, one end

is slightly positioned over the other 19. The significance in this is illustrated in Fig. 5, which shows how the arching of the surface of the shaft 5 of the rotor 4 and the length of the arch correspond to the arching and length of a quarter of the periphery of the seal disk 7 which is able to rotate in the disk chamber 8. In this manner, as the spiral conveniently extends about the shaft in a revolution of slightly over 360°, when one end of the spiral is about to slide out of one slot 9 of the disk, the spiral is already sliding into the next slot 9 at the other end. Thus, the rotor and the seal disk always rotate such that they are tightly connected to each other, one full revolution of the rotor 4 corresponding to a revolution of 90° of the disk.

Fig. 3a and 3b show the operation of the pump in two different positions of the rotor 4 and the seal disk 7 relative to each other. As the rotor rotates supported and bearing-mounted on the pump body 17, a point of the spiral slides into a slot 9 of the seal disk 7 that is entering the pump chamber, while a preceding point of the spiral is simultaneously exiting a slot of the disk 7 in the pump chamber. The construction that expands in the middle of the spiral together with the volume space that collects the pumped oil and expands in the center of the chamber generates great suction power in the pump at low revolutions . This is important in particular when pumping fluids which have high viscosity, such as oil. As the spiral rotates, the seal disk 7 which rotates along with the spiral and about its axis 18 generates in the pumped fluid a pressure which removes the fluid via the discharge duct 3 positioned on the delivery side of the pump. The tightness and large volume of the pump allow the pump rotor to be rotated at small rotation speeds and yet ensure good pumping capacity.

The invention is not limited merely to the examples referred to above; instead many variations are possible within the scope of the inventive idea defined by the claims .