Pump, pump system and method for pumping a medium

Abstract

The invention relates to a pump, a pump system and a method for pumping a medium. The pump for pumping medium comprises an inlet, an outlet, a drivable spindle and at least two follower spindles, wherein the drivable spindle and the at least two follower spindles are provided at a mutual angle to each other.

Claims

1. A screw spindle pump for pumping fuel, oil and crude, comprising an inlet through which fuel is suctioned, an outlet, a drivable spindle and two follower spindles, wherein the drivable spindle and the two follower spindles are provided at a mutual angle to each other, and wherein the inlet is provided on a front side of the pump and the pump is provided on a rear side with a motor and wherein the angled relationship between the drivable spindle and the follower spindles allows the pump housing to be smaller than that of a conventional pump having a drive shaft and spindle shafts lying in one line, such that the screw spindle pump is adapted to be introduced into a liquid conduit for use as a submersible pump and wherein the pump further includes a pipe encasement seal which surrounds the pump and prevents leakage of suctioned fuel between the pump and the liquid conduit.

2. The screw spindle pump as claimed in claim 1, wherein the drivable spindle and the two follower spindles are provided in a visually asymmetrical configuration.

3. The screw spindle pump as claimed in claim 2, wherein the drivable spindle and the two follower spindles are provided in an asymmetrical force configuration.

4. The screw spindle pump as claimed in claim 1, wherein the screw spindle pump has an outer diameter in the range of 100-300 mm.

5. The screw spindle pump as claimed in claim 1, wherein the two follower spindles are provided with a smaller diameter than the drivable spindle.

6. A screw spindle pump system comprising a pump as claimed in claim 1.

7. A method for pumping a medium, comprising pumping the medium using the screw spindle pump as claimed in claim 1.

8. The method as claimed in claim 7, further comprising positioning the screw spindle pump in a space of a ship and pumping medium out of the ship.

9. The method according to claim 7, comprising introducing the screw spindle pump into the liquid conduit.

10. The method according to claim 9, wherein the liquid conduit comprises a monitoring pipe or ventilation pipe.

11. The screw spindle pump as claimed in claim 1, wherein the screw spindle pump has an outer diameter in the range of 100-200 mm.

12. The pump as claimed in claim 1, wherein the outer diameter of the screw spindle pump is 150 mm.

13. A method for pumping fuel, oil, or crude out of a ship, the method comprising pumping the fuel, oil, or crude using a screw spindle pump, comprising an inlet through which the fuel, oil, or crude is suctioned, an outlet, a drivable spindle and at least two follower spindles, wherein the drivable spindle and the at least two follower spindles are provided at a mutual angle to each other, and wherein the inlet is provided on a front side of the pump and the pump is provided on a rear side with a motor, further comprising introducing the screw spindle into a liquid conduit wherein the pump has an encasement seal which surrounds the pump to prevent leakage of suctioned fuel between the pump and the liquid conduit.

14. The method according to claim 13, wherein the liquid conduit comprises a monitoring pipe or ventilation pipe.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, features and details of the invention are elucidated on the basis of a preferred embodiment thereof, wherein reference is made to the accompanying figures, in which:

(2) FIG. 1 shows a cross-section of a conventional spindle pump according to the invention;

(3) FIG. 2A shows a cross-section of a conventional spindle pump;

(4) FIG. 2B shows a cross-section of the pump according to the invention;

(5) FIGS. 3 and 4 show views of the pump of FIG. 2B;

(6) FIG. 5 shows a view of the pump of FIG. 2B with inner pipe seal;

(7) FIG. 6 shows a view of a T-piece for use in the pump system;

(8) FIG. 7 shows a view of the pump of FIG. 2B being introduced into a pipe;

(9) FIG. 8 shows a view of the inner pipe seal;

(10) FIG. 9 shows a view of a T-piece;

(11) FIG. 10 shows a view of a test setup; and

(12) FIGS. 11-13 show results obtained with the pump according to the invention.

DESCRIPTION OF THE INVENTION

(13) A pump 1 (FIG. 1) is provided with a central drive shaft/drive spindle 2 and two non-driven shafts/follower spindles 3. Spindles 2, 3 are arranged in a housing 4. In a conventional pump 5 (FIG. 2A) drive shaft 6 and spindle shafts 7 lie in one line A and are here both visually symmetrical and force-symmetrical.

(14) In pump 8 according to the invention (FIG. 2B) drive shaft 6 and the two spindle shafts 7 do not lie in one line and are here asymmetrical from both a visual and a force viewpoint. The centre line B connecting the centres of the first follower spindle and drive shaft 6 lies at an angle z to centre line C connecting the centres of the second follower spindle and drive shaft 6. It will be apparent that, with the same dimensions, housing 9 of pump 8 can be smaller than that of a conventional pump 5. Because of this arrangement, the pump 8 may be introduced into a liquid conduit, such as a monitoring pipe or ventilation pipe.

(15) In the shown embodiment the diameter of spindle 7 is smaller than the diameter of drive shaft 6.

(16) Pump 8 (FIGS. 3 and 4) is provided on rear side 11 with a motor 10. In the shown embodiment motor 10 is driven hydraulically using hydraulic hoses 12. In the shown embodiment the length of pump 8 is about 613 mm, the diameter about 150 mm, and the weight amounts to about 50-60 kg. Situated on front side 13 is an inlet 14 through which fuel can be suctioned and discharged through outlet 14A. Pump 8 (FIG. 4) is embodied such that a pump capacity of about 70 mVhour is possible at a pressure of about 3 bar and a viscosity of about 100 cSt at about 30 C. The hydraulic specifications here are a maximum pressure of 210 bar and a maximum flow between 54 and 63 l/min, depending on the type of motor.

(17) Pump 8 (FIG. 5) can be provided with an inner pipe seal 15, also referred to as pump encasement seal, which surrounds the pump 8 and prevents leakage between the pump and a liquid conduit of suctioned fuel to the surrounding area through openings in the liquid conduit, such as a tube or pipe 16, in which pump 8 is placed. Tube or pipe 16 is preferably of the DN250 type. In the shown embodiment inner pipe 15 is of a plastic material such that it can be cut or severed to a suitable length, subject to for instance the length of tube 16. The plastic is for instance a plastic which can unfold or expand.

(18) Pipe 16 is preferably provided with a T-piece 17 (FIG. 6). T-piece 17 is provided with a first flange 18 of DN200 on the feed side of the medium. A second flange 19 of DN200 is provided on the side for discharge of the medium, and a third flange 20 of DN300 is preferably provided with a cover 21. Arranged on or close to cover 21 are openings 22 with seals 23 for passage of hydraulic hoses 12.

(19) Pump 8 can be placed in pipe 16 using a winch system 24 (FIG. 7). Other methods are also possible. Inner pipe 15 (FIG. 8) can be introduced via flange 20 into pipe 16 together with pump 8. Cover 21 (FIG. 9) is then provided for the purpose of sealing flange 20. In this configuration inner pipe 15 is suspended inside the T-piece, whereby the pump can later be pulled out of the T-piece again.

(20) Tests have shown that the pump according to the invention has a pump capacity at different viscosities which is substantially constant over a wide operating range. A pump has thus been tested at different viscosities of 57.4 and 11.4 mm.sup.2/s, at a temperature of respectively 36 C. and 20 C. and a pressure of about 3.0 bar, a rotation speed of 2600 rpm, a net positive suction head (NPSH) of respectively 5.9 and 4.8 mWC. The pump capacity at the different viscosities amounted to respectively 1189 and 1173.3 l/min. The power consumption in the comparative measurements amounted to respectively 13.0 and 9.9 kW. The pump capacity is therefore roughly constant at the different viscosities.

(21) Further tests have shown that the pump capacity remains substantially constant at a difference in pressure in the range of at least 0-15 bar. Over this pressure range the variation in a capacity of 1200 l/min amounts to less than 100 l/min at the different viscosities.

(22) In tests with a test setup 25 (FIG. 10), wherein fuel from tank 26 can be pumped around via adjustable flow resistance 27, it has been found that pump 8 can be carried through differently shaped pipe parts of pipe 16.

(23) Tests have shown that passage through a bend of a pipe with a 230 mm diameter is possible. This is likewise the case for a 45 S-bend at a pipe diameter of 184 mm and a 70 bend at a pipe diameter of 230 mm.

(24) For the purpose of pumping a medium, a pump is introduced into a pipe which is connected to a fuel tank. This is for instance a fuel tank in a double-walled ship, wherein the fuel tank is provided between the two walls. The pump is placed in the pipe, preferably in combination with the inner pipe seal. This inner pipe prevents undesirable leakage of the pump fuel to the surrounding area. The pump is provided with a motor which in a currently preferred embodiment is driven hydraulically. The hydraulic hoses and the inner pipe seal are lowered into the pipe along with the pump. The pump suctions the fuel out of the tank and pumps it into the conduit. The conduit is preferably provided with a T-piece where the hydraulic hoses are carried out of the pipe and to which the outer end of the inner pipe is internally attached. The pumped medium is discharged via the other side. A fuel tank can in this way be pumped empty, and undesirable leakage is avoided.

(25) Further tests confirm the operation of the pump according to the invention. The pump has thus been tested over a pressure difference of 0-6 bar, at different viscosities of 6 cSt to 900 cSt at 2600 rpm (FIG. 11). The pump has further been tested with a so-called Eaton motor (FIG. 12) with flow rates up to 1200 l/min, i.e. 72 m.sup.3/hour. In other tests, use has been made of a Leistritz pump. Further results (FIG. 13) show the above stated, substantially constant behaviour of the pump according to the invention. Said tests were performed with pump 1. With a different dimensioning and/or configuration of pump 1 it is also possible according to the invention to utilize pump 1 in other fields of operation.

(26) The invention is by no means limited to the above described preferred embodiments thereof. The rights sought are defined by the following claims, within the scope of which many modifications can be envisaged. It is thus possible to also employ the pump as described above in other applications. It is thus for instance possible to envisage placing the pump according to the invention into an oil pipe, for instance in case of malfunction. Other applications according to the invention are also possible.