Double-sealing structure of multi-stage pump

Abstract

The utility model relates to the technical field of multistage pumps, in particular to a double-seal structure of a multistage pump, which comprises a pump body and a rotating shaft, a first mechanical seal is arranged between the pump body and the rotating shaft, a cooling cover is fixed on the top of the pump body, a cooling cavity is formed between the cooling cover and the top surface of the pump body, and the top of the first mechanical seal is located in the cooling cavity. A second mechanical seal is arranged between the cooling cover and the rotating shaft, the cavity wall of the cooling cavity is outwards communicated with a cooling liquid inlet and a cooling liquid outlet, and an inductive probe used for detecting cooling liquid is installed on the cooling cover or the pump body. The first mechanical seal is cooled through cooling liquid circulation, and the service life of the first mechanical seal is prolonged; when the first mechanical seal fails, due to the fact that cooling liquid circulates in the cooling cavity and leaked liquid media are mixed with the cooling liquid, the inductive probe can detect changes of liquid properties and output signals, the leaked liquid media can be found in time, a user is reminded of failure of the first mechanical seal, and maintenance is conducted in time.

Description

Technical Field

[0001] The present application relates to the technical field of multi-stage pumps, and in particular to a double-channel sealing structure of a multi-stage pump. Background Art

[0002] A multistage pump is a pump with two or more impellers. It is a type of centrifugal pump. It relies on the rotation of the impeller to obtain centrifugal force to pump the liquid. The output water pressure of a multistage pump can be very high. Multistage pumps can be used in many fields such as petroleum, chemical industry, machinery, fire protection, etc. The main feature of a multistage pump is high head.

[0003] The multi-stage pump of the prior art, with reference to the utility model patent with announcement number CN202348683U, discloses a vertical multi-stage pump. With reference to the drawings of the patent, the vertical multi-stage pump has a water inlet and a water outlet, and a plurality of impellers are arranged in the pump chamber. The impellers are arranged and distributed along the axial direction of the rotating shaft. The motor on the top of the pump body drives the rotating shaft to rotate through the coupling, and the rotating shaft drives all the impellers to rotate, thereby realizing multi-stage pressurization of the liquid and achieving high lift.

[0004] In the above-mentioned related technologies, the top of the pump body and the rotating shaft are sealed by a mechanical seal to prevent the liquid in the pump chamber from leaking upward along the outer wall of the rotating shaft. However, the output pressure of the multistage pump is very high, and the mechanical seal position is also under great pressure. During operation, the temperature is high due to friction, which is prone to leakage and damage. In addition, when the mechanical seal leaks, it is difficult for personnel to detect it in time, resulting in continuous leakage. Utility Model Content

[0005] The present application provides a multi-stage pump double-channel sealing structure, which can cool the mechanical seal and facilitate personnel to promptly detect leakage of the mechanical seal, thereby performing maintenance and repair in a timely manner to avoid continuous leakage failures.

[0006] The present application provides a multi-stage pump double-channel sealing structure, which adopts the following technical solution:

[0007] A multistage pump double-channel sealing structure comprises a pump body and a rotating shaft, a first mechanical seal is arranged between the pump body and the rotating shaft, a cooling hood is fixed on the top of the pump body, a cooling cavity is formed between the cooling hood and the top surface of the pump body, the top of the first mechanical seal is located in the cooling cavity, a second mechanical seal is arranged between the cooling hood and the rotating shaft, a cavity wall of the cooling cavity is connected to the outside with a coolant inlet and a coolant outlet, and an induction probe for detecting the coolant is installed on the cooling hood or the pump body.

[0008] By adopting the above technical solution, the coolant in the cooling chamber cools and dissipates the heat of the first mechanical seal through heat conduction. When the first mechanical seal fails, the liquid medium delivered by the pump body enters the cooling chamber. Since there is coolant circulating in the cooling chamber, the leaked liquid medium mixes with the coolant, causing the composition of the liquid in the cooling chamber to change. The induction probe can detect the change and output an electrical signal to the alarm device, so that the leaked liquid medium can be discovered in time, reminding the user that the first mechanical seal has failed and timely maintenance can be performed.

[0009] Optionally, the coolant inlet is opened on the pump body, and the coolant outlet is opened on the cooling cover.

[0010] By adopting the above technical solution, the height position of the coolant inlet is arranged lower than the coolant outlet, and a bottom-in-top-out method is adopted. When the liquid pump for conveying the coolant stops, the coolant can still be retained in the cooling chamber due to gravity, thereby avoiding the liquid pump connected to the coolant inlet from idling due to lack of water when starting next time.

[0011] Optionally, the coolant inlet and the coolant outlet are respectively located on both sides of the radial direction of the rotating shaft.

[0012] By adopting the above technical solution, the path length of the coolant passing through the cooling cavity is extended as much as possible, thereby improving the cooling effect.

[0013] Optionally, the coolant inlet and the coolant outlet are both threadedly connected with quick connectors.

[0014] By adopting the above technical solution, the quick connector is connected with the matching connector, so that the external pipeline can be installed easily and the assembly and disassembly are convenient.

[0015] Optionally, the sensing probe is a thermal conductivity probe.

[0016] By adopting the above technical solution, the leaked liquid medium mixes with the coolant, causing the thermal conductivity of the liquid in the cooling chamber to change. The induction probe based on the thermal conductivity principle can detect the change, thereby identifying the leakage.

[0017] Optionally, a vent is provided near the top of the pump body, and a vent bolt is threadedly connected to the vent.

[0018] By adopting the above technical solution, the space at the top of the pump body is connected to the outside world after the bleed bolt is screwed out, so as to remove the gas in the pump body to ensure its normal operation and promote the pump body to be filled with liquid so as to be able to pump water.

[0019] Optionally, a positioning ring is fixed to the side of the cooling cover facing the pump body, and the positioning ring is plugged into the pump body.

[0020] By adopting the above technical solution, the positioning ring is plugged into the pump body, and the positioning ring is used to provide a positioning effect for the installation of the cooling cover.

[0021] Optionally, the sensing probe is a transparency sensor or a liquid leakage sensor.

[0022] By adopting the above technical solution, the transparency sensor and the liquid leakage sensor can also detect and identify the mixed liquid after leakage.

[0023] In summary, the present application includes at least one of the following beneficial technical effects:

[0024] 1. Cool the first mechanical seal by circulating the coolant to extend the service life of the first mechanical seal;

[0025] 2. When the first mechanical seal fails, since there is coolant circulating in the cooling chamber, the leaked liquid medium mixes with the coolant, and the sensing probe can detect the change in the liquid properties and output a signal. Therefore, the leaked liquid medium can be discovered in time, reminding the user that the first mechanical seal has failed and performing maintenance in time.

[0026] 3. The coolant inlet and outlet are both equipped with quick connectors, which are convenient for disassembly and assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a cross-sectional view of a double-channel sealing structure of a multi-stage pump according to an embodiment.

[0028] Explanation of the accompanying drawings: 1. Pump body; 11. Rotating shaft; 12. Impeller; 10. First mechanical seal; 2. Cooling cover; 20. Second mechanical seal; 21. Cooling chamber; 22. Positioning ring; 31. Coolant inlet; 32. Coolant outlet; 33. Quick connector; 4. Induction probe; 13. Vent port; 14. Vent bolt. DETAILED DESCRIPTION

[0029] The present application is further described in detail below in conjunction with the accompanying drawings.

[0030] Embodiment 1:

[0031] Reference Figure 1 This embodiment discloses a multi-stage pump double-pass sealing structure, including a pump body 1 and a rotating shaft 11. The rotating shaft 11 penetrates the pump body 1 from the top of the pump body 1. The top of the rotating shaft 11 is connected to the output shaft of the motor through a coupling. The lower part of the rotating shaft 11 is located in the pump body 1 and fixed with multiple impellers 12. It should be noted that the pump body 1 includes a pump cover. A first mechanical seal 10 is arranged between the pump body 1 and the rotating shaft 11. The first mechanical seal 10 establishes a rotating seal between the top of the pump body 1 and the rotating shaft 11, which serves as a first seal.

[0032] A cooling hood 2 is fixed on the top of the pump body 1, and a cooling cavity 21 is formed between the cooling hood 2 and the top surface of the pump body 1. The top of the first mechanical seal 10 is located in the cooling cavity 21. A positioning ring 22 is fixed on the side of the cooling hood 2 facing the pump body 1. The positioning ring 22 is plugged into the pump body 1. The positioning ring 22 is used to provide a positioning effect for the installation of the cooling hood 2. The cooling hood 2 and the pump body 1 are sealed by setting a sealing ring, which is sleeved outside the positioning ring 22. The cooling hood 2 and the pump body 1 are fixed by bolts. The rotating shaft 11 passes through the cooling hood 2, and a second mechanical seal 20 is provided between the cooling hood 2 and the rotating shaft 11. The second mechanical seal 20 establishes a rotating seal between the top of the cooling hood 2 and the rotating shaft 11 as a second seal.

[0033] The wall of the cooling chamber 21 is connected to the outside with a coolant inlet 31 and a coolant outlet 32, wherein the coolant inlet 31 is opened on the pump body 1, and the coolant outlet 32 ​​is opened on the cooling cover 2. This arrangement makes the height position of the coolant inlet 31 lower than the coolant outlet 32, and adopts a bottom-in-top-out method, which conforms to the cooling principle. When the liquid pump that transports the coolant stops, the coolant can still be retained in the cooling chamber 21 due to gravity, avoiding the liquid pump connected to the coolant inlet 31 from running idle due to lack of water when it is started next time. The coolant inlet 31 and the coolant outlet 32 ​​are respectively located on both sides of the radial direction of the rotating shaft 11. This arrangement extends the path length of the coolant through the cooling chamber 21 as much as possible, thereby improving the cooling effect.

[0034] The coolant inlet 31 and the coolant outlet 32 ​​are both threadedly connected with quick connectors 33, which are connected to the matching connectors to facilitate installation of external pipes and convenient assembly and disassembly.

[0035] An induction probe 4 for detecting the coolant is installed on the cooling cover 2 or the pump body 1 , and a detection end of the induction probe 4 is located in the cooling cavity 21 .

[0036] The induction probe 4 of this embodiment is a thermal conductivity probe, which is a thermal conductivity sensor. The thermal conductivity probe is designed based on the principle of heat exchange. A thermal resistor sensing element is placed on each side of the probe in contact with the medium, one side is for heating and the other side is for heat sensing. When the medium flows, the heat generated by the heating resistor will be taken away by the flowing medium, thereby forming a temperature difference between heating and heat sensing, which is converted into a corresponding electrical signal through the relationship between the temperature difference and the medium flow rate. Since the flow rate of the coolant in the cooling chamber 21 remains consistent, when the liquid transported by the pump body 1 leaks into the cooling chamber 21, the liquid mixes with the coolant, causing the properties of the liquid in the cooling chamber 21 to change, and the thermal conductivity will also change, so it can be detected by the thermal conductivity probe.

[0037] The pump body 1 is provided with an air vent 13 near the top, and the air vent 13 is threadedly connected with an air vent bolt 14. If the pump body 1 is started without exhausting the air in it, the impeller 12 will run idle and cannot pump water. After unscrewing the air vent bolt 14, the space at the top of the pump body 1 is connected to the outside world, in order to exhaust the gas in the pump body 1 to ensure its normal operation and promote the pump body 1 to be filled with liquid so that water can be pumped. When the liquid flows out from the air vent 13, the air vent bolt 14 is reinstalled and tightened.

[0038] The implementation principle of a multi-stage pump double-channel sealing structure in an embodiment of the present application is: the coolant in the cooling chamber 21 cools and dissipates heat to the first mechanical seal 10 through heat conduction, and at the same time the coolant will also reduce the temperature of the contacting rotating shaft 11, and the reduction in the temperature of the rotating shaft 11 can also cool the first mechanical seal 10 in contact therewith.

[0039] When the first mechanical seal 10 fails, the liquid medium transported by the pump body 1 will not directly leak to the outside, but enter the cooling chamber 21. Since coolant circulates in the cooling chamber 21, the leaked liquid medium mixes with the coolant, causing the thermal conductivity of the liquid in the cooling chamber 21 to change. The sensing probe 4 based on the thermal conductivity principle can detect the change and output an electrical signal to the alarm device. Therefore, the leaked liquid medium can be discovered in time, reminding the user that the first mechanical seal 10 has failed and timely maintenance can be performed.

[0040] Embodiment 2:

[0041] The difference between the second embodiment and the first embodiment is that the sensing probe 4 is a transparency sensor or a liquid leakage sensor.

[0042] The transparency sensor is a sensor that calculates the transparency of the liquid by measuring the absorbance of light by substances in the liquid and converts it into an electrical signal. When the liquid transported by the pump body 1 leaks into the cooling chamber 21, the liquid mixes with the coolant, causing the properties of the liquid in the cooling chamber 21 to change, and the transparency of the liquid will also change. Therefore, the leakage can be detected by the transparency sensor.

[0043] The principle of the liquid leakage sensor is to detect leakage through changes in the light transmittance or reflectivity of the liquid. The liquid leakage sensor using the optical principle usually includes a light emitting diode and a photodiode. The principle is to detect leakage through changes in the light transmittance or reflectivity of the liquid. When the liquid transported by the pump body 1 leaks into the cooling chamber 21, the liquid mixes with the coolant, causing the properties of the liquid in the cooling chamber 21 to change, and the light transmittance of the liquid will also change, so the leakage can be detected by the liquid leakage sensor.

[0044] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A multistage pump double-channel sealing structure, comprising a pump body (1) and a rotating shaft (11), wherein a first mechanical seal (10) is arranged between the pump body (1) and the rotating shaft (11), characterized in that: A cooling hood (2) is fixed on the top of the pump body (1), a cooling cavity (21) is formed between the cooling hood (2) and the top surface of the pump body (1), the top of the first mechanical seal (10) is located in the cooling cavity (21), a second mechanical seal (20) is provided between the cooling hood (2) and the rotating shaft (11), a cavity wall of the cooling cavity (21) is connected to the outside with a cooling liquid inlet (31) and a cooling liquid outlet (32), and an induction probe (4) for detecting the cooling liquid is installed on the cooling hood (2) or the pump body (1).

2. The multistage pump double-channel sealing structure according to claim 1 is characterized in that: The cooling liquid inlet (31) is opened on the pump body (1), and the cooling liquid outlet (32) is opened on the cooling cover (2).

3. The multistage pump double-channel sealing structure according to claim 1, characterized in that: The cooling liquid inlet (31) and the cooling liquid outlet (32) are respectively located on two radial sides of the rotating shaft (11).

4. The multistage pump double-channel sealing structure according to claim 1, characterized in that: The coolant inlet (31) and the coolant outlet (32) are both threadedly connected with quick connectors (33).

5. The multi-stage pump double-channel sealing structure according to claim 1, characterized in that: The induction probe (4) is a thermal conductivity probe.

6. The multi-stage pump double-channel sealing structure according to claim 1, characterized in that: The pump body (1) is provided with an air vent (13) near the top, and the air vent (13) is internally threadedly connected with an air vent bolt (14).

7. The multi-stage pump double-channel sealing structure according to claim 1, characterized in that: A positioning ring (22) is fixed on the side of the cooling cover (2) facing the pump body (1), and the positioning ring (22) is plugged into the pump body (1).

8. The multistage pump double-channel sealing structure according to claim 1, characterized in that: The sensing probe (4) is a transparency sensor or a liquid leakage sensor.

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