RU2736677C1 - Centrifugal vertical pump - Google Patents

Abstract

FIELD: pumping equipment.

SUBSTANCE: invention can be used for pumping out of containers. Centrifugal pump with a flow part immersed into the pumped medium comprises an engine, a support plate, a shaft line formed by one or more suspensions, a seal assembly, formed by two end seals and chamber with barrier or gate fluid between them. Pump is equipped with a system for monitoring the state of the barrier or gate liquid, comprising at least a liquid level meter and a pressure measurement device, each of which has indicator part and part reacting to fluid parameter change. Parts reacting to change of fluid parameter are located between two end seals, directly in chamber with barrier or breech liquid.

EFFECT: invention is aimed at improving reliability of centrifugal pump operation and reducing probability of its unpredictable failures.

3 cl, 1 dwg

Description

The invention relates to pumping equipment and can be used to create installations for pumping out of containers, for example, a water-oil mixture with the presence of abrasive mechanical impurities.

The problem of creating pumps, especially semi-submersible ones, operating in difficult conditions, is to increase their reliability, maintainability and facilitate routine maintenance, which, due to the specifics of working conditions, are performed quite often and are quite expensive. This is, in part, due to insufficient control of the state of both structural elements and the parameters of the barrier / barrier fluid, especially in the case of the location of the mechanical seals directly behind the impeller. One of the main conditions for ensuring the safe operation of semi-submersible centrifugal pumping units when pumping explosive and fire hazardous liquids is reliable reliable control of the tightness of the shaft seals.

Known is a centrifugal vertical pump with a flow path submerged in the pumped medium, containing an engine, a shaft line formed by one or more suspensions, a seal assembly formed by two mechanical seals and a separation chamber filled with a cooling and lubricating liquid, a flow path with an impeller located in it, limited a seal housing and a pump casing with a branch, a leakage sensor located below the level of the bearings in the inner cavity of the shafting (RU 71710 U1, IPC F04D 7/04, 20.03.2008).

Known centrifugal pump containing a flow path formed by an impeller located in the pump casing, a main seal assembly, an auxiliary seal, a bearing support, a motor, and, as an auxiliary seal, a magnetic coupling with a protective screen is used (RU 71711 U1, IPC F04D 7/04 , 20.03.2008).

A centrifugal pump with a flow path submerged in the pumped medium is known, containing an engine, a shafting formed by one or more suspensions, a flow path formed by an impeller located in the pump housing and a drain, a leakage sensor, characterized in that there is a separation cavity between the impeller and the shaft line with a double mechanical seal located in it, the shafts of the shaft line are installed in rolling bearings, while the cooling of the lower mechanical seal is carried out due to the flow of the pumped liquid through the channel in the pump unit casing, and the upper mechanical seal is cooled by lubricating and cooling liquid poured into the separating cavity, the leakage sensor is located below the level of the bearings in the inner cavity of the shafting, below the level of the bearings there is a cavity for collecting leaks with a hole closed with a plug, and the upper part of the upper suspension is located above the level of the plate (RU 74975, U1, IPC F04D 7 / 04, 20.07.2008).

A common disadvantage of the known designs is the absence of a device for monitoring the presence and state of the barrier liquid in the chamber between the mechanical seals and the impossibility of timely detection of the failure of the lower seal, which can lead to the failure of the pump, and when pumping explosive and fire hazardous media can lead to an explosion or fire.

Known pumping unit consisting of an engine, a base plate, a shafting, a chamber with a barrier fluid located between two mechanical seals, a leak sensor, moreover, the unit is equipped with a barrier fluid level control device installed above the base plate of the unit and connected through a pipe system with a chamber of the barrier fluid , which consists of a container in the lid of which a float-type indicator with a scale is installed, and a liquid level sensor or a pressure sensor (US Pat. RU No. 2435987 IPC F04D 7/00, 10.12.2011 - prototype).

The disadvantage of the known technical solution is the lack of systemic monitoring of the state of the barrier fluid in the chamber between the end seals and the impossibility, as a result, of timely prevention of damage to structural elements. Since the presence of a long system of pipelines separating the liquid, directly washing the seals and the liquid from which the parameters are taken by the barrier liquid level control device, leads to inaccurate measurement results. This is especially true when using pumps in a wide temperature range (from - 60 degrees C in the Far North, to + 45 degrees C in the southern regions). in this case, the oil in these pipelines either thickens or freezes (which will lead to incorrect readings of the control system or its complete failure), and in the case of replacing the oil with an antifreeze liquid, the measurement accuracy will not be satisfactory (due to its large intrinsic volumetric expansion in the specified interval temperatures).

In addition, in the presence of excessive pressure in the tank (and / or pumping a liquid with a high pressure of saturated vapor), in the event of a depressurization of the lower mechanical seal, the liquid (at the point of its measurement) will not drop and its level readings will be within the permissible range (i.e. will not correspond to the dangerous situation), i.e. the barrier liquid level control device does not fully fulfill its functions, since situations are possible when there will be no indication of a violation of the integrity of the lower mechanical seal, in case of its actual failure.

It should also be noted that the very presence of such large-sized pipelines (1-3 m long) leads to an increase in the weight and size characteristics of the product, an increase in its cost and a decrease in the reliability of work.

The objective of the invention and its technical result is to improve the reliability of the centrifugal pump and reduce the likelihood of unpredictable failures.

The technical result is achieved by the fact that in a known centrifugal pump with a flow path submerged into the pumped medium containing an engine, a base plate, a shaft line formed by one or more suspensions, a seal assembly formed by two mechanical seals and a chamber with a barrier or barrier liquid between them, in which, according to the invention, it is equipped with a system for monitoring the state of the barrier or barrier liquid, including at least a device for measuring the level of the liquid and a device for measuring pressure, each of which has an indicator part and a part that responds to a change in the parameter of the liquid, and parts that respond to a change parameter of the liquid, located between two mechanical seals, directly in the chamber with a barrier or barrier liquid. In addition, the system for monitoring the state of the barrier or barrier liquid contains a device for measuring temperature, and all devices for measuring the parameters of the liquid are electronic or electromechanical.

The specified set of features exhibits new properties, consisting in the fact that in the case of their use, the reliability of the centrifugal pump is increased and the likelihood of unpredictable pump failures is reduced.

A schematic diagram of a centrifugal vertical pump is shown in the drawing, where:

1. Flow part,

2. Electric motor,

3. Stove,

4. Shafting,

5. Suspension,

6. Mechanical seals,

7. Barrier fluid chamber,

8. Liquid level measuring device (part that responds to a change in the liquid parameter),

9. Pressure measuring device (a part that responds to a change in a liquid parameter),

10. Temperature measuring device (a part that responds to a change in a liquid parameter),

11. Impeller,

12. Outlet branch pipe.

A centrifugal pump with a flow passage 1 submerged into the pumped medium, contains an engine 2, a base plate 3, a shaft line 4 formed by one or more suspensions 5, a seal assembly formed by two mechanical seals 6 and a chamber 7 with a barrier or barrier liquid between them, and in chamber 7 contains a device for measuring the level of liquid 8, a device for measuring pressure 9, and a device for measuring temperature 10, each of which has an indicator part (not shown in Fig. 1) and a part that responds to a change in the parameter of the liquid, and the parts that respond to a change in the parameter of the liquid are located between two mechanical seals, directly in the chamber with a barrier or barrier liquid 7. The shaft line 4 is connected to the impeller 11. The pump housing has an outlet 12.

The device operates as follows.

Before starting work, the pump is immersed in a container with liquid and plate 3 is fixed. The liquid fills the pump casing.

When the engine 2 is started, the torque is transmitted by the shaft line 4 to the impeller I, which creates a fluid pressure and raises it to the outlet 12.

The state of the blocking or barrier liquid during the entire operation of the pump is constantly monitored by devices 8, 9, 10, moreover, since all parts of the devices reacting to a change in the parameter of the liquid are located directly in the chamber 7, then the information coming through the wires to the indicator part of the devices reflects the real state of the barrier or barrier liquid, and, consequently, the seals 6. In the event of an abnormal state of the barrier or barrier liquid, a signal is given about the presence of this abnormal situation, which reduces the likelihood of failure of structural elements and increases the reliability of operation and the resource of the pump as a whole, (due to the timely behavior of routine maintenance and elimination of emergency situations).

Thus, the use of the proposed invention will improve the reliability of the pump, reduce the likelihood of unpredictable failures, simplify and reduce the cost of the pump design.

Claims (3)

1. A centrifugal pump with a flow path submerged into the pumped medium, containing a motor, a base plate, a shaft line formed by one or more suspensions, a seal assembly formed by two mechanical seals and a chamber with a barrier or barrier liquid between them, characterized in that it is equipped with a system monitoring the state of a barrier or barrier liquid, including at least a liquid level measuring device and a pressure measuring device, each of which has an indicator part and a part that responds to a change in the liquid parameter, and the parts that respond to a change in the liquid parameter are located between two mechanical seals , directly in a chamber with a barrier or barrier liquid. 2. A centrifugal pump according to claim 1, characterized in that the system for monitoring the state of the barrier or barrier liquid comprises a temperature measuring device. 3. The centrifugal pump according to claim 1, characterized in that the device for measuring the parameters of the liquid is made of electronic or electromechanical.

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