Pump device and pump system

Abstract

Provided are a pump device and a pump system capable of properly detecting deterioration of a bearing even in a pump device for pumping up a liquid fuel material having corrosiveness.　A pump device 3 is installed inside a tank 2 in which a corrosive liquid fuel material is stored, and pumps up the liquid fuel material. The pump device 3 comprises: a pump casing 4 constituted of a material having corrosion resistance to the liquid fuel material; a motor 6 installed in the pump casing 4 and generating driving force of the pump device 3; a rotary shaft 7 installed in the pump casing 5 and rotated by the driving force of the motor 6; a bearing 8 installed in the pump casing 5 and rotatably journaling the rotary shaft 7; a first sensor 9 provided outside the pump casing 5 and capable of detecting deterioration of the bearing 8; and a protection member 15 covering the first sensor 9.

Description

Pumping equipment and pumping systems

[0001] The present invention relates to a pumping device and pumping system for pumping corrosive liquid fuel materials such as liquid ammonia.

[0002] Canned motor pumps have been used as pumping devices for pumping liquid fuel materials (see, for example, Patent Document 1). Conventional canned motor pumps are equipped with electrical detection means (sensors) for detecting the wear condition of the bearings of the rotating shaft of the motor that generates the rotational driving force for the impeller, thereby monitoring the pump's condition. Conventional canned motor pumps are used to pump liquefied natural gas (LNG) and liquefied hydrogen. Furthermore, conventional canned motor pumps are used on land, and their outer surfaces are exposed to the atmosphere.

[0003] Japanese Patent Application Laid-Open No. 2001-304180

[0004] In recent years, liquid ammonia, which does not emit carbon dioxide when burned, has attracted attention as a liquid fuel material. Furthermore, unlike Patent Document 1, liquid ammonia requires a structure in which the outside of the canned motor pump is in contact with the handled liquid. Unlike liquefied natural gas (LNG) or liquefied hydrogen, liquid ammonia is corrosive. Therefore, there is a risk of corrosion of components constituting a device for monitoring the pump status (e.g., electrical detection means (sensors) and cables for detecting bearing deterioration).

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a pump device and a pump system for pumping a corrosive liquid fuel material.

[0006] The pump device of the present invention is a pump device that is installed inside a tank that stores a corrosive liquid fuel material and pumps up the liquid fuel material, and includes: a pump casing made of a material that is corrosion-resistant to the liquid fuel material; a motor that is installed inside the pump casing and generates a driving force for the pump device; a rotating shaft that is installed inside the pump casing and rotated by the driving force of the motor; a bearing that is installed inside the pump casing and rotatably supports the rotating shaft; a first sensor that is provided outside the pump casing and can detect deterioration of the bearing; and a protective member that covers the first sensor.

[0007] According to this configuration, the first sensor provided on the outside of the pump casing is covered with a protective member, which prevents the first sensor from being corroded by the liquid fuel material and protects the first sensor from vibrations of the pump casing, thereby enabling proper detection of bearing wear.

[0008] In the pump device of the present invention, it is preferable that the protective member prevents the first sensor from being corroded by exposure to the liquid fuel material.

[0009] Furthermore, the pump device of the present invention preferably includes a sensor cable connected to the first sensor and extending to the outside of the pump device, and the sensor cable is preferably plated with a material that is corrosion-resistant to the liquid fuel material.

[0010] According to this configuration, the sensor cable is plated, and therefore corrosion of the sensor cable by the liquid fuel material can be suppressed.

[0011] In the pump device of the present invention, it is preferable that the protective member covers the first sensor and the sensor cable, and that the protective member is filled with an inert gas.

[0012] With this configuration, it is possible to prevent fuel gas obtained by vaporizing the liquid fuel material from entering the protective member, and it is possible to more appropriately protect the first sensor and the sensor cable.

[0013] The pump device of the present invention preferably includes a second sensor capable of detecting that fuel gas vaporized from the liquid fuel material has entered the interior of the protective member.

[0014] With this configuration, even if fuel gas does enter the protective member, it can be detected and countermeasures can be taken at an early stage.

[0015] In the pump device of the present invention, the second sensor is preferably a pressure sensor.

[0016] By using a pressure sensor as the second sensor, it is possible to detect the intrusion of fuel gas into the protective member from a drop in pressure inside the protective member.

[0017] In the pump device of the present invention, the first sensor is preferably an acceleration sensor, a displacement sensor, or a temperature sensor.

[0018] By using an acceleration sensor as the first sensor, it is possible to detect bearing wear by measuring the vibration of the pump casing. Also, by using a displacement sensor as the first sensor, it is possible to detect bearing wear by measuring the displacement of the rotating shaft. Also, by using a temperature sensor as the first sensor, it is possible to detect wear of the bearing by measuring heat generation from the bearing.

[0019] The pump system of the present invention comprises a tank for storing a corrosive liquid fuel material, and a pump device installed inside the tank for pumping up the liquid fuel material. The pump device comprises a pump casing made of a material that is corrosion-resistant to the liquid fuel material, a motor installed inside the pump casing for generating driving force for the pump device, a rotating shaft installed inside the pump casing for being rotated by the driving force of the motor, a bearing installed inside the pump casing for rotatably supporting the rotating shaft, a first sensor installed outside the pump casing for detecting wear of the bearing, and a protective member covering the first sensor.

[0020] This pump system also prevents the first sensor from being corroded by the liquid fuel material and protects it from vibrations of the pump casing, thereby enabling proper detection of bearing deterioration.

[0021] According to the present invention, deterioration of bearings can be appropriately detected even in a pump device that pumps corrosive liquid fuel material.

[0022] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pump device according to an embodiment of the present invention will now be described with reference to the accompanying drawings. In the present embodiment, a pump device used as a canned motor pump for liquid ammonia will be described as an example.

[0024] The configuration of a pump device according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is an explanatory diagram showing the configuration of a pump system according to this embodiment, and Fig. 2 is a cross-sectional view of the pump device according to this embodiment. As shown in Figs. 1 and 2, the pump system 1 includes a tank 2 that stores liquid ammonia (a corrosive liquid fuel material) and a pump device 3 that is installed inside the tank 2 and pumps the liquid ammonia. The tank 2 includes a tank casing 4 made of a material that is resistant to corrosion by liquid ammonia (e.g., stainless steel), and the pump device 3 includes a pump casing 5 made of a material that is resistant to corrosion by liquid ammonia (e.g., stainless steel).

[0025] 2, the pump casing 5 contains a motor 6 that generates a driving force for the pump device 3, a rotating shaft 7 that is rotated by the driving force of the motor 6, and a pair of upper and lower bearings 8 that rotatably support the rotating shaft 7. The bearings 8 may deteriorate over many years of use. Therefore, the pump device 3 is provided with a pair of sensors 9 (first sensors) that are capable of detecting deterioration of the bearings 8 and are provided on the outside of the pump casing 5 near each of the pair of upper and lower bearings 8.

[0026] The sensor 9 is, for example, an acceleration sensor that measures vibrations of the pump casing 5. When the bearing 8 deteriorates, the pump casing 5 vibrates. By measuring this vibration, it is possible to detect that the bearing 8 has deteriorated.

[0027] Alternatively, the sensor 9 may be a displacement sensor that measures the displacement of the rotating shaft 7. When the bearing 8 deteriorates, the rotating shaft 7 is no longer supported in its original position and displaces. By measuring this displacement, it is possible to detect that the bearing 8 has deteriorated.

[0028] The sensor 9 may also be a temperature sensor that measures the temperature of the bearing 8. When the bearing 8 deteriorates, heat is generated from the bearing 8 due to friction with the rotating shaft 7. By measuring this heat generation, it is possible to detect that the bearing 8 has deteriorated.

[0029] 1 and 2, a power supply unit 10 that supplies power to the pump device 3 and a measuring device 11 that receives output signals from a pair of upper and lower sensors 9 are provided outside the tank 2. A motor cable 12 that supplies power from the power supply unit 10 is connected to the motor 6, and sensor cables 13 that transmit output signals to the measuring device 11 are connected to the pair of upper and lower sensors 9, respectively. The motor cable 12 is covered with a protective tube 14 made of a material (such as stainless steel) that is resistant to corrosion by liquid ammonia.

[0030] One feature of this embodiment is that the pump device 3 is provided with a protective tube 15 (protective member) that covers the sensor 9. The sensor cable 13 that extends from the sensor 9 to the outside of the pump device 3 and is connected to the measuring device 11 is also covered with the protective tube 15. The protective tube 15 is, for example, a flexible tube. The protective tube 15 prevents the sensor 9 and the sensor cable 13 from being corroded by exposure to liquid ammonia. The protective tube 15 also protects the sensor 9 and the sensor cable 13 from vibrations of the pump device 3.

[0031] The sensor cable 13 is preferably plated with a material that is resistant to corrosion by liquid ammonia. For example, the sensor cable 13 is made of copper and plated with aluminum. This protects the sensor cable 13 from liquid ammonia.

[0032] 1, a nitrogen tank 16 that supplies nitrogen gas (inert gas) as a purge gas and a nitrogen gas pipe 17 through which the nitrogen gas supplied from the nitrogen tank 16 flows are provided outside the tank 2. The nitrogen gas pipe 17 is connected to a protective pipe 15, and the nitrogen gas supplied from the nitrogen tank 16 is filled into the protective pipe 15 from the nitrogen gas pipe 17.

[0033] As shown in FIG. 1, the nitrogen gas pipe 17 is provided with a pressure adjusting unit 18 that keeps the pressure inside the nitrogen gas pipe 17 constant, a pressure sensor 19 that detects changes in the pressure of the nitrogen gas inside the nitrogen gas pipe 17, and a flow rate sensor 20 that detects changes in the flow rate of the nitrogen gas inside the nitrogen gas pipe 17.

[0034] The pressure adjusting unit 18 is preferably configured by, for example, a pressure reducing valve, and makes the inside of the protective tube 15 higher in pressure than the outside of the protective tube 15. This makes it possible to prevent ammonia gas vaporized from liquid ammonia from entering the protective tube 15 through a gap between the protective tube 15 and the outer surface of the pump casing 5.

[0035] If ammonia gas enters the protective tube 15, the pressure inside the protective tube 15 will decrease. The pressure sensor 19 (second sensor) detects this pressure decrease, and it can be detected that ammonia gas has entered the protective tube 15 and the nitrogen gas pipe 17.

[0036] According to the pump device 3 of this embodiment, the sensor 9 provided on the outside of the pump casing 5 is covered by the protective tube 15. This prevents the sensor 9 from being corroded by liquid ammonia and protects it from vibrations of the pump casing 5. This allows deterioration of the bearing 8 to be detected appropriately.

[0037] Furthermore, the sensor cable 13 connected to the sensor 9 can also be protected from corrosion by covering it with the protective tube 15. By plating the sensor cable 13 with aluminum or the like, corrosion of the sensor cable 13 by liquid ammonia can be further suppressed. In addition, by filling the protective tube 15 with nitrogen gas, it is possible to suppress the intrusion of ammonia gas into the protective tube 15.

[0038] Furthermore, by providing the pressure sensor 19, even if ammonia gas enters the protective tube 15, it can be detected and countermeasures can be taken at an early stage.

[0039] INDUSTRIAL APPLICABILITY As described above, the pump device according to the present invention has the effect of being able to appropriately detect deterioration of bearings, and is useful when used as a canned motor pump for liquid ammonium, etc.

[0040] REFERENCE SIGNS LIST 1 Pump system 2 Tank 3 Pump device 4 Tank casing 5 Pump casing 6 Motor 7 Rotating shaft 8 Bearing 9 Sensor 10 Power supply device 11 Measuring device 12 Motor cable 13 Sensor cable 14 Protective tube 15 Protective tube 16 Nitrogen tank 17 Nitrogen gas piping 18 Pressure adjustment unit 19 Pressure sensor 20 Flow rate sensor

Claims

1. A pump device that is installed inside a tank in which a corrosive liquid fuel material is stored and pumps up the liquid fuel material, comprising: a pump casing made of a material that is corrosion-resistant to the liquid fuel material; a motor that is installed within the pump casing and generates a driving force for the pump device; a rotating shaft that is installed within the pump casing and rotated by the driving force of the motor; a bearing that is installed within the pump casing and rotatably supports the rotating shaft; a first sensor that is provided on the outside of the pump casing and can detect deterioration of the bearing; and a protective member that covers the first sensor.

2. The pump device according to claim 1, wherein the protective member prevents the first sensor from being corroded by exposure to the liquid fuel material.

3. A pump device as described in claim 1 or 2, further comprising a sensor cable connected to the first sensor and extending to the outside of the pump device, the sensor cable being plated with a material that is corrosion-resistant to the liquid fuel material.

4. The pump device according to claim 3, wherein the protective member covers the first sensor and the sensor cable, and the protective member is filled with an inert gas.

5. A pump device according to claim 1 or 2, further comprising a second sensor capable of detecting that fuel gas vaporized from the liquid fuel material has entered the interior of the protective member.

6. The pump device according to claim 5, wherein the second sensor is a pressure sensor.

7. The pump device according to claim 1 or 2, wherein the first sensor is an acceleration sensor, a displacement sensor or a temperature sensor.

8. A pumping apparatus as claimed in claim 1 or 2, wherein the liquid fuel material is liquid ammonia.

9. A pump system comprising: a tank for storing a corrosive liquid fuel material; and a pump device installed inside the tank and pumping up the liquid fuel material, wherein the pump device comprises: a pump casing made of a material that is corrosion-resistant to the liquid fuel material; a motor installed within the pump casing and generating a driving force for the pump device; a rotating shaft installed within the pump casing and rotated by the driving force of the motor; a bearing installed within the pump casing and rotatably supporting the rotating shaft; a first sensor provided on the outside of the pump casing and capable of detecting deterioration of the bearing; and a protective member covering the first sensor.

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