DK141382B - Hydraulically driven pump unit immersed in the pump medium. - Google Patents

Description

(w! (11) PUBLICATION WRITING 1 ^ 1382 DENMARK isn intci.3 '(21) Application No. 5017/68 (22) Filed on 17 · Oct. 19 ^ 8 (23) Runs 1 7 · Oct. 1 9 ^ 8

(44) The application submitted and Q

the petition published on 5 · HLSJ? · 1 9 ^ 0

DIRECTORATE OF

PATENT AND TRADE MARKET (30) Priority requested from it

Oct 18 1967, 170172, NO

(71) PATENTS AND DEVELOPMENTS A / S, Helldal, Fana, NO.

(72) Inventor: Frank Mohn, 55 Straumeveien, Kråkenes, Fana, NO.

(74) Plenipotentiary in the proceedings:

International Patent Office.

(54) Hydraulically driven pump unit immersed in the pump medium.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a hydraulically driven pump assembly immersed in the pump medium, in particular for use on board tankers for the transport (unloading) of cargo oil, solvents and similar loads, with a submersible pump containing a pump rotor accommodated in a pump housing, and a a high pressure hydraulic drive motor located near the pump motor and connected thereto via a relatively short vertical drive shaft, a transport medium for the pump medium running from the pump housing up to the ship's deck, and a drainage chamber disposed between the pump rotor and the drive motor and enclosing the drive shaft, which is sealed by the drive shaft against the pump motor via a first sealing device, respectively, against the drive motor via a second sealing device.

The term "pumping unit" is understood to mean not only the pump itself with pump housing, drive motor, drive shaft and pump rotor, but also transport line, drive medium lines and other equipment that are lowered down the load together with the pump.

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Carriers find it desirable to be able to carry a number of different loads on one and the same keel, ie. different loads in different tanks and with different, varying sizes of loads. The invention aims, among other things, to solve the problem of fulfilling this desire in an efficient and safe way. To this end, separate loading and unloading devices are used for each tank, so as to prevent direct mixing of the loads themselves, and according to the invention, a pump unit submerged in the load is used for each tank. With this arrangement, however, not all problems have been solved.

It is an object of the present invention to provide a pump unit that is specially protected so that it can be absorbed in the cargo in a cargo tank on board a tanker and kept submerged in the cargo for a relatively long time without the risk of , that leakage of propellant should occur in the load and that leakage of the load should occur in the propellant or in the other drive mechanism of the pump.

It is generally difficult to obtain a fully satisfactory seal of the pump drive shaft during operation. In other words, it is especially the seals at the pump drive shaft that are exposed to leakage, but also other parts of the pump and pump unit must be ensured an effective seal to prevent any possibility of leakage.

In practice, however, one must always expect that sooner or later a more or less strong leakage can occur at the drive shaft seals as a result of overheating, wear, sealing failure and similar front claims. Therefore, it is difficult to guarantee a leak-proof seal of a pump unit, especially at the pump shaft.

From the specification of U.S. Patent No. 3,200,753, a single system is known to counteract mixing of pump medium and drive medium at the pump drive shaft.

A drainage chamber is used which encloses the pump drive shaft between a first seal against the pump medium and a second seal against the drive medium. The pump axis runs horizontally in the illustrated embodiment. From the drainage chamber, a drainage outlet extends outward to free air from the lower portion of the drainage chamber.

By incorporating the pump unit submerged in the load, during most of the immersion time, such as during the tanker sailing, a constant static pressure will be applied from the load to the pump unit, which will result in a certain effect on seals etc. During the unloading operation, however, in addition to the static pressure from the load, additional strong stresses occur as a result of the rotational movement of the drive shaft, and the risk of welding cake will thereby be increased. During the unloading operation, the static pressure conditions will also change as the drop in the load level in the tank, which also creates further complications.

In the case of a submersible pump unit which must be able to be immersed in the load for a longer period and then must be fully operational, firstly, certain structural problems which tend to cause leakage must be solved and secondly, certain sealing problems caused by starting the pump and operating it under different, i.e. varying pressure conditions. Thirdly, certain problems arising from the influence of the various pump media to be handled by the pump and in which the pump unit is submerged must be solved. The pump unit according to the invention applies in particular to different types of tankers for unloading different types of cargo, which are covered by terms such as "solvent cargo", "chemical cargo", "parcel tank cargo", "special tank cargo" etc. Such cargoes primarily include products from the petrochemical industry that have had and continue to be in rapid development with ever new products. These include loads such as lubricating oil, animal and vegetable oils, liquid fertilizers, products such as "coconut" oil, palm oil, molasses, liquid caustic soda, various types of acids, such as sulfuric acid, hydrochloric acid, hydrochloric acid etc., and susceptible products such as wine and cognac. The present invention aims to solve the problems that such loads can cause.

It will be understood that a leakage of propellant (pressurized oil), lubricant, etc., may represent a major problem with certain loads. For certain special delicate loads, even minimal amounts of leakage medium can cause tremendous damage and can potentially destroy the entire load or at least substantially impair its quality. Therefore, in order to fulfill the purpose of the invention, it is essential that any possibility of leakage of propellant, lubricant, etc. can be countered inwardly in the load.

It will further be appreciated that a removal of the pumping medium (load) inwardly into the vital parts of the pump assembly via the drive medium, lubricant, etc., may represent further major problems. In particular, certain aggressive loads can cause major problems. First, such aggressive loads could accelerate the breakdown of seals, especially the seals at the pump drive shaft "so as to cause a leakage of propellant into the load - with the problems this causes - a further leakage of pumping medium (load) inward in the drive medium - with the problems that this causes. In other cases, the cargo, although not

are particularly aggressive against seals, etc., nevertheless being detrimental to the propellant or vital parts associated with the propellant circuit. IN

in some cases, the load, if leaked into the propellant circuit, may damage or damage the propellant itself, while in other instances, due to the mixture of cargo and propellant, it may cause explosion hazard in the tank compartment or associated compartments or cause danger of poisoning of man and environment.

The present invention is intended to counteract any possibility of leakage of pumping medium (load) inwards into the propellant, lubricant, etc.

141382 4

The pump assembly according to the invention is characterized in that it has a separating zone which separates all areas containing propellant medium - such as the area of the propellant motor and the area around the supply and drain lines of the propellant motor - from areas where the pumping medium (load) is located, said separating zone also the drainage chamber disposed at the lower portion of the separating zone comprises at least a portion of the separating zone, i. at least a portion containing the drainage chamber is adapted to be kept at a pressure lower than the pressure of the driving medium and / or the pressure of the pumping medium, said lower pressure being preferably obtained by a connection via a pressure relief line for atmospheric pressure, and the pumping unit at the bottom portion of the drainage chamber communicates with leakage medium removal devices which may have penetrated the drainage chamber.

By using a separation zone according to the invention for the entire extent of the pump unit, it has been possible to define a possible leakage from the load or from the drive medium to the separation zone. This has been made possible according to the invention by providing controlled pressure conditions at least in certain parts of the separation zone which comprise the drainage chamber around the pump drive shaft. Hereby, by means of controlled pressure conditions, it is possible to ensure that any leakage occurs in only a certain direction, ie. in the direction from the load (pumping medium) or from the drive medium inward to the drainage chamber, but not the opposite way. By providing the pump unit with devices for removing the leakage medium that may have penetrated the drainage chamber, even small quantities of leakage can be detected and furthermore the leakage medium can be removed from the separation zone before any special damage to the other parts of the pump unit can be done with accessories. .

The solution according to the invention is based on a combination of the measures according to claim 1, these measures alone solving the problem according to the invention in part, but jointly enabling complete control and complete control of the leakage which may arise. In this connection, it is crucial that the entire pump unit is protected by a separation zone. This divide zone may optionally be divided into separate zone portions which are controlled separately. However, in a specially described embodiment, the drainage chamber forms part of the separation zone with direct communication between the drainage chamber and the other parts of the separation zone, so that any leakage, wherever it occurs in the separation zone, can be directed to the drainage chamber at the lower end of the separation zone and then removed therefrom with devices. , which communicates with the bottom portion of the drainage chamber. Furthermore, it is essential that such pressure conditions prevail that the leak occurs in only a certain direction, and not the opposite way, and in order to achieve such pressure conditions it is essential that the leakage medium removal devices communicate with the bottom portion of the drainage chamber. An accumulation or substantial collection of leakage medium in the drainage chamber can easily change the pressure conditions at the drainage chamber to give uncontrolled drainage conditions. In practice, it is possible to blow away the leakage medium from the drainage chamber without significantly changing the pressure conditions therein.

When using e.g. a pressure medium driven ejector mechanism having its suction inlet located just above the bottom portion of the drainage chamber, the leakage medium can be removed in a controlled and efficient manner as needed and as it accumulates at the bottom portion while maintaining the pressure in the drainage chamber due to the suction effect of the ejector mechanism. desired level, even in the relatively short time intervals where any leakage medium is removed. The suction can be intermittent and does not depend on continuous ejector operation. In addition, the ejector mechanism achieves a pressure drop against the lower part of the separation zone, which acts to further support the drainage effect.

A preferred embodiment of the pump assembly according to the invention is characterized in that the drive motor supply line is arranged internally in the drive motor drain line and said drain line communicates with the chamber in a housing enclosing the drive motor, while said drain line and said housing zone are enclosed by said housing.

With this arrangement, a simple structural solution is obtained for additional protection and shielding of the high-pressure pipe used, which supplies pressure medium to the drive motor, and a corresponding protection and shielding of the drive motor itself, so that any breakage of the high-pressure side will be intercepted and smoothed in the enclosing drain or return side. The risk of leakage of propellant into the separation zone is thereby further reduced.

Another preferred embodiment of the pump assembly according to the invention is characterized in that a region between the drive motor and the second sealing device in which the drive shaft is housed in shaft bearings is traversed by a drive medium passage which communicates with a passage between the drive motor and its drain line.

With this arrangement, a favorable pressure-relieving discharge of the drive medium is obtained from the drive motor via a lubrication system for the drive shaft bearings for the drive motor drain line. Such pressure relief in combination with the lubrication system creates an effective lubrication while keeping the pressure conditions of the propellant in front of the drainage chamber at a suitably low pressure level. By using the pressure-relieved propellant - ie. the pressure medium returned from the drive motor - as a lubricant, ensures a certain circulation of moderate pressure lubricant towards the sealant side seal, thus achieving controlled lubrication and at the same time a controlled monitoring of the sealant side seal using a moderate drivmediumtryk.

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The invention will be explained in more detail below in an embodiment with reference to the drawing, in which FIG. 1 shows a pump installation containing a pump assembly according to the invention; FIG. 2 is a side view of the embodiment of FIG. 1; FIG. 3 is a sectional view taken along line III-III of FIG. 1, FIG. 4 shows a larger scale vertical section through the lower part of the one shown in FIG.

1, and FIG. 5 shows a detail of FIG. 4.

The FIG. 1 and 2, the pump and pump installation are particularly designed for use on board tankers of the type referred to as "parcel tankers", ie tankers designed to accommodate different ship loads in the various cargo spaces and where it may be desirable to use one pump in each tank.

However, the illustrated pump can also be used in conventional tankers or in other vessels where such pumps are needed, the pump installation being adapted to pump any fluids such as oils, solvents and molasses. In particular, the aim of the pump and pump installation is to avoid any leakage or possibility of leakage to and from the pump drive mechanism, so as to firstly avoid contamination of the pump medium with foreign materials from the pump drive mechanism and then prevent the active pump medium from accessing the pump. drive mechanism.

FIG. 1 and 2 show a pump disposed in a pump housing 10 which is stationary in a recess 11 in a bottom 12 of a ship tank 13 such that the pump is immersed in the pump medium in the tank 13. During operation, the pump is subjected to a certain feed pressure, which depends on the fluid height in the tank. The pump is thus positioned correctly, even in the case of viscous pump media and easily volatile pump media. The pump drive shaft 14 is positioned vertically and the pump inlet 15 is located at the lower end of the pump just above the bottom of the recess 11 and is directed downward to the bottom of the recess. The outlet 16 of the pump first extends laterally outward from the pump and then upwardly to communicate with a vertically extending pressure line 17. The pressure line 17 passes through a removable hatch cover 18 attached to a hatch 19 in the top 20 of the ship tank and is connected over the hatch cover by a conveyor line 21. not shown departure point. The pump housing 10 is supported by a first housing part 22, a second housing part 23 and a pipe 24. The pipe 24 runs concentrically with the pump shaft 14 and vertically upwards through the hatch cover 18 via a pipe nozzle 25.

The FIG. 1 and 2 the pump and pump installation can be supplied from the factory as a pre-assembled unit. The unit, which consists of the pump housing 10, the pressure line 17, the housing parts 22, 23 and the pipe 24, thus constitutes a built-in unit. The conduit 17 and pipe 24 are fixed in the vertical direction at appropriate intervals by guide shoes 26, 27 arranged vertically displaceable on rails 28, 29 which are attached to a tank wall 30. After removing the hatch cover 18, the unit 10, 17, 22, 23, 24 are controlled in a controllable manner, respectively, lifted free of the tank and lowered into position in the tank through the associated hatch opening by means of a portable crane or other lifting equipment on board the ship or by means of a crane on land. Thus, if desired, the entire pump unit can still be lifted without any particular difficulty, for repair, inspection or replacement of certain parts, after which it can again be lowered into place in the tank in ready-to-use condition.

The pump rotor 32, FIG. 4, is connected via a relatively short drive shaft 14 to a hydraulic high-pressure motor 33, so that a very compact assembly of pump rotor 32 and drive motor 33 is obtained. This arrangement offers several operational advantages, but there are also problems in protecting the drive motor 33 and the drive shaft bearings 34-36 and the drive motor hydraulic circuits 37-38 against the pumping medium in the tank 13.

The hydraulic circuit of the drive motor is secured in such a way that a supply pipe o 2 37 which brings the pressure oil to the motor 33 with a pressure of e.g. 150 kg / cm is accommodated in a return pipe 38 in which the pressure oil may have a pressure e.g. 1.5-2 2 kg / cm. If for some reason the pressure oil should leak from the tube 37 into the tube 38, the pressure oil will not cause any damage. The tube 38 is again accommodated in the tube 24 which forms the shielding tube for the tube 38 (and 37) and other tubes described below so that a possible leakage from the tube 38 can be collected in the tube 24. These safety measures are important in the cases where where to avoid contamination of the charge with pressure oil. Not only does it prevent leakage outward to the charge, but also that the various wires are protected against shocks and shocks, from attacks by aggressive load fluids, penetration of such fluids into the pressure oil, etc. At the top of the hatch cover 18, fig · 1, is shown a coupling to a hydraulic circuit 41-42 via a valve arrangement 43 having a bypass valve 44 for isolating the circuit 37, 38.

FIG. 4 shows details of the embodiment of FIG. 1 and 2.

The pump is a conventional centrifugal pump containing a pump rotor 32 accommodated in a pump chamber 45 located between three housing portions 17a, 17b, 17c, and the rotor is sealed to the pump housing 10 by seals 46-48. Just above the pump housing 10, a chamber 49 is formed in the housing part 22 which via a port opening 50, FIG. 1, coronates with the pumping medium in the tank 13 such that a static fluid pressure prevails in the chamber recess 49 surrounding the shaft 14 in front of a first set of seals 51, 52 sealing the drive shaft 14 over a bearing foot piece 53a. Between the seals 51, 52 and a higher-level set of seals 53, 54 is arranged a metal support 55a having a radial aperture 55b, and between the ring 55a and the shaft 14 as well as the seals 52 and. 53, a drain chamber 55 is further described hereinafter.

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Between an inwardly extending flange portion 56 of the housing portion 22 and the bearing foot piece 53a, a tubular support portion 57 is supported which carries the bearings 34-36 of the drive shaft 14. The flange portion 56 carries the drive motor 33, and between the underside of the drive motor and the top of the bearing foot 53a, a bearing chambers 58 are provided in the carrier 57 containing hydraulic oil from the hydraulic circuits of the drive motor 33. At 59a, a main outlet for return oil is shown from the drive motor 33. At 59, a drain line is shown from the drive motor. This conduit 59 communicates via a conduit 60 in 56, a conduit 61 in the carrier portion 57 and a pipe piece 62 with the lower portion of the chamber 58. At the upper portion of the chamber 58, a conduit 63 communicates with an oil discharge chamber 64. The chamber 64 is formed in a housing portion 65 which freely surrounds the drive motor 33 and communicates above with the return pipe 38 of the hydraulic circuit. The main outlet 59a of the drive motor opens freely in the chamber 64 and oil is removed. If leakage occurs in the drive motor itself or its conduit connections 37, 59, this leakage will be trapped in chamber 64 without causing any damage and is discharged via pipe 38 along with the remaining return oil. At 66, a sliding valve is shown which is adjustable from the chamber 49 in the housing portion 22 via the port opening 50; 1. The valve 66 can, as needed, regulate the amount of oil leaving the conduit 59 in direct connection with the chamber 64 of the housing portion 65 via a duct 67, thereby allowing a certain amount of the oil to pass outside the passage 60-63. and directly to chamber 64. It is also possible to close the entire passage 60-63 when repairs or inspection are required for pump rotor, shaft, bearings, seals and similar components. However, during operation, passages 60-63 are supplied with a sufficient amount of oil from the drive motor to ensure a lively circulation of the oil in chamber 58, thus providing a satisfactory lubrication of bearings 34-36.

The housing portion 23 communicating above via the shielding tube 24 with atmospheric pressure surrounds the exposed housing portion 65 so that a protective chamber 68 is formed between the housing portion 23 and the housing portion 65 and its coupling with the flange portion 56. The housing portion 23 attached to the housing portion 22 communicates below. via a downward pipe connection 69 and a horizontal channel 70 with the drainage chamber 55 between the two sets of seals 51, 52 and 53, 54 on the shaft 14, so that the drainage chamber 55 also communicates with the atmospheric pressure. In this way, a certain pressure drop is secured to the drainage chamber via each of the two sets of seals, with static pressure prevailing on the opposite side of the sealing set 51, 52 depending on the fluid height of the tank 13, while on the opposite side of the sealing set. 53, 54 there is a pressure corresponding to the pressure of the oil. These fluid pressures individually form a barrier so as to avoid any leakage from chamber 55 past the respective sealing sets. If leakage occurs beyond the sealing sets 51, 52 or 53, 54 of the chamber 55, the pressure in the chamber 55 will

Claims (2)

The time could be kept so low as to avoid any leakage from chamber 55 through the adjacent sealing sets. In order to keep the leakage of chamber 55 under control and to remove fluid which has accumulated in chamber 55 and adjacent conduit connection 70, 69, 68, whether from the sealing sets 51, 52 or 53, 54 or other leaks of pumping medium or pressure oil introduced into the chamber 68, the pump is provided with a fluid drainage arrangement. At 71, a substantially vertical suction tube is shown whose lower end edge 72 is cut obliquely and opens at the bottom of channel 70 at the lower end of tube 69. Suction tube 71 is connected in chamber 68 to an end of an ejector tube 72 which also accommodates a supply pipe 73 for compressed air or steam at a pressure of 7-10 kg / cm, and the opposite end of which communicates with a discharge pipe 74. It is intended that the drainage arrangement should be capable of being intermittently activated by appropriate remote control. Before the pump starts, the ejector mechanism can e.g. is initiated to expel any fluid collected. By means of a suitable apparatus not shown, the amount of leakage can be determined by collecting the drained fluid from the ejector mechanism. In addition, upon inspection of the fluid leaked into the drainage chamber 55 or adjacent connections, it will be possible to ascertain the nature and location of the leak, so that a quick decision can be made as to whether repairs are necessary. As shown in FIG. 3, the supply pipe and discharge pipe of the ejector mechanism are also received shielded in the shielding pipe 24, so that a leakage in the pipes 73, 74 will also not cause damage to the charge or the pump drive mechanism. With the illustrated arrangement, an efficient enclosure of the drive motor and associated pressure oil lines as well as the ejector mechanism is ensured. drain for drainage fluid. In this way, a pump installation has been obtained, which can be immersed in so-called arbitrary pump media, without resulting in damage. Claims. 1. Hydraulically driven pump unit immersed in the pump medium, in particular for use on board tankers for transport (unloading) of cargo oil, solvents and similar loads, with a pump submersible in the pump medium containing a pump rotor incorporated in a pump housing and a high pressure hydraulic a drive motor disposed close to the pump rotor and connected thereto via a relatively short vertical drive shaft, a transport medium for the pump medium running from the pump housing up to the ship's deck, and a drainage chamber disposed between the pump rotor and the drive motor and enclosing the drive shaft and sealed by the drive shaft against the pump motor via a first sealing device or against the drive motor via a second sealing device,