Mechanical seal cooling structure for pump and online cleaning method

Abstract

A pump seal cooling structure, comprising a first pipeline, a second pipeline and a cooler, the upstream end of the first pipeline is connected with the pump outlet, the downstream end is connected with the process medium passage inlet of the cooler, a first normally open valve is arranged on the first pipeline, the upstream end of the second pipeline is connected with the process medium passage outlet of the cooler, the downstream end is communicated with the cooling cavity of the pump seal, a pilot valve is arranged on the second pipeline. The present application has simple structure and low modification cost, can realize the purpose of quick and flexible online cleaning of the pump seal on the basis of ensuring the cooling effect of the pump seal, effectively meets the actual needs of enterprises, can clean the pump seal online by using the cooling structure, has simple operation and is convenient, does not need additional power or cleaning agent, and is a high-efficiency online cleaning method.

Description

Technical Field

[0001] This invention relates to the chemical industry, and in particular to a pump mechanical seal cooling structure and an online cleaning method. Background Technology

[0002] Chemical plants typically use circulating water pumps with high inlet pressures for the process medium, reaching 22 kg / m³. This process medium is a mixture of dusty water, impurities, and process condensate, resulting in a high impurity content. To save space and cost, companies often directly use the high-pressure process medium (25-28 kg / m³) from the pump outlet. After cooling, this medium enters the cooling chamber of the mechanical seal, where it carries away the heat generated by friction and into the pump body. However, due to the high impurity content of the process medium itself, a significant amount of impurities accumulates on the pump's casing, causing wear and leakage of the process medium under its own pressure. This leads to on-site pollution and frequent shutdowns for seal maintenance.

[0003] Therefore, how to effectively prevent the mechanical seal of the pump from being worn by deposited impurities without changing the cooling water source is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] One of the objectives of this invention is to address the shortcomings of existing technologies by providing a pump mechanical seal cooling structure that is simple in structure and low in modification cost. While ensuring the cooling effect on the pump mechanical seal, it can achieve rapid and flexible online cleaning of the pump mechanical seal, effectively meeting the actual needs of enterprises.

[0005] The second objective of this invention is to provide a method for online cleaning of pump mechanical seals using the aforementioned pump mechanical seal cooling mechanism. This method is simple and convenient to operate, requires no additional power or cleaning agent, and is a highly efficient online cleaning method.

[0006] One of the technical solutions to achieve the objective of this invention is: a pump mechanical seal cooling structure, including a first pipeline, a second pipeline, and a cooler. The upstream end of the first pipeline is connected to the pump outlet, and the downstream end is connected to the process medium channel inlet of the cooler. A first normally open valve is provided on the first pipeline. The upstream end of the second pipeline is connected to the process medium channel outlet of the cooler, and the downstream end is connected to the cooling chamber of the pump mechanical seal. A drain valve is provided on the second pipeline.

[0007] The cooler is a shell-and-tube heat exchanger, with the shell side serving as the cooling medium passage and the tube side serving as the process medium passage.

[0008] A water bucket is installed below the drain valve.

[0009] Preferably, a second normally open valve is provided on the second pipeline, and the second normally open valve is close to the pump mechanical seal.

[0010] The second technical solution to achieve the objective of this invention is: an online cleaning method for pump mechanical seals, employing any of the above-mentioned pump mechanical seal cooling structures, comprising the following steps:

[0011] 1) Close the first normally open valve and open the drain valve to allow the process medium in the pump to be quickly discharged through the cooling chamber of the pump mechanical seal, the second pipeline, and the drain valve;

[0012] 2) Close the drain valve and open the first normally open valve to complete the online cleaning of the pump mechanical seal.

[0013] Preferably, the opening time of the drain valve in step 1) is 5-10 seconds.

[0014] Preferably, in step 1), after closing the first normally open valve, the second normally open valve is closed, the drain valve is opened, and then the second normally open valve is opened again.

[0015] Preferably, in step 2), the second normally open valve is closed, then the drain valve is closed, and the first normally open valve and the second normally open valve are opened.

[0016] The above technical solution has the following beneficial effects:

[0017] 1. The pump mechanical seal cooling structure includes a first pipeline, a second pipeline, and a cooler. The upstream end of the first pipeline is connected to the pump outlet, and the downstream end is connected to the inlet of the process medium channel of the cooler. A first normally open valve is installed on this first pipeline; that is, under normal circumstances, a portion of the high-pressure process medium enters the process medium channel of the cooler through the first pipeline for cooling treatment, serving as the cooling medium for the pump mechanical seal. The upstream end of the second pipeline is connected to the outlet of the process medium channel of the cooler, and the downstream end is connected to the cooling chamber of the pump mechanical seal. A drain valve is installed on the second pipeline. Under normal circumstances, the drain valve is closed. The cooled high-pressure process medium enters the cooling chamber of the pump mechanical seal through the second pipeline, absorbing the heat generated by the sealing surface of the pump mechanical seal. Because the pressure of the high-pressure process medium is greater than the pressure of the process medium inside the pump, under the action of a small pressure difference, the high-pressure process medium carries heat into the pump, mixing with the process medium inside the pump, thus achieving the purpose of cooling the pump mechanical seal. The cooling structure has few components and simple connections, resulting in low modification costs. It is widely applicable to pump mechanical seals used in pipelines supplying high-pressure, high-turbidity process media. When using this cooling structure for online cleaning of pump mechanical seals, the first normally open valve is closed to disconnect the cooling structure from the high-pressure process media. The drain valve is then opened to connect with the atmosphere, creating a significant pressure difference between the pump mechanical seal cooling chamber and the drain valve (far greater than the pressure difference between the high-pressure process media at the pump outlet and the process media inside the pump). Under this significant pressure difference, a portion of the process media inside the pump (22 kg pressure) is rapidly discharged through the cooling chamber, the second pipeline, and the drain valve. During this rapid discharge, the pump mechanical seal sealing surface and cooling chamber are efficiently flushed, removing deposited impurities. These impurities are then discharged through the second pipeline and the drain valve, achieving online cleaning in just a few seconds. This highly efficient and low-cost online cleaning method is a safe and effective solution. After the online cleaning is completed, close the drain valve and open the first normally open valve. The process medium inside the pump cannot flow out, and the high-pressure process medium at the pump outlet enters the pump under the pressure difference, thus transforming it into a normal cooling structure.

[0018] 2. A water tank is installed below the drain valve to receive the process media discharged from the drain valve during the online cleaning process, so as to avoid on-site pollution caused by these process media.

[0019] 3. A second normally open valve is installed on the second pipeline. The second normally open valve is close to the pump mechanical seal. Under normal circumstances, the second normally open valve is in the open state. In special circumstances, such as when the cooler needs to be repaired or to protect the drain valve, the second normally open valve can be closed to meet the actual needs of the enterprise.

[0020] 4. In the online cleaning method of the present invention, after closing the first normally open valve, the second normally open valve is closed, the drain valve is opened, and then the second normally open valve is opened again. In this way, the resistance is small when opening the drain valve, which extends the service life of the drain valve and can also effectively reduce the risk of high-speed process media discharged from the drain valve causing harm to maintenance personnel, thus meeting the actual needs of enterprises.

[0021] 5. In the online cleaning method of the present invention, step 2) closes the second normally open valve, then closes the drain valve, and opens the first normally open valve and the second normally open valve. In this way, the resistance is small when closing the drain valve, which extends the service life of the drain valve and can also effectively reduce the risk of high-speed process media discharged from the drain valve causing harm to maintenance personnel, thus meeting the actual needs of enterprises.

[0022] According to the applicant's verification, the pump mechanical seal cooling structure and online cleaning method modified by this invention can effectively prevent wear on the sealing surface due to deposited impurities while ensuring normal cooling of the pump mechanical seal. This extends the maintenance cycle of the pump mechanical seal from the traditional few days to half a month to 2-3 months, greatly reducing the intensity and frequency of maintenance work.

[0023] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details. Attached Figure Description

[0024] Figure 1 This is a connection diagram of the present invention.

[0025] In the attached diagram, 1 is the first pipeline, 2 is the second pipeline, 3 is the cooler, 4 is the water tank, a is the first normally open valve, b is the second normally open valve, and c is the drain valve. Detailed Implementation

[0026] Example 1

[0027] See Figure 1 The pump mechanical seal cooling structure includes a first pipeline 1, a second pipeline 2, and a cooler 3. Typically, the first and second pipelines have the same specifications. The cooler is a shell-and-tube heat exchanger, with the shell side serving as the cooling medium passage and the tube side as the process medium passage. The upstream end of the first pipeline 1 is connected to the pump outlet, where the pressure of the high-pressure process medium reaches 25-28 kg. The downstream end is connected to the inlet of the process medium passage in the cooler 3. A first normally open valve a is installed on the first pipeline 1. The upstream end of the second pipeline 2 is connected to the outlet of the process medium passage in the cooler 3, and the downstream end is connected to the cooling chamber of the pump mechanical seal. A second normally open valve and a drain valve c are installed on the second pipeline 2. The second normally open valve is located near the pump mechanical seal, and the drain valve is located near the cooler. A water tank 4 is located below the drain valve c.

[0028] Under normal cooling conditions, both the first and second normally open valves are open, while the drain valve is closed. Room temperature water is used as the cooling medium, flowing through the shell side. The high-pressure process medium (25-28 kg) at the pump outlet enters the cooler via the first pipeline. After cooling, it is discharged into the cooling chamber of the pump's mechanical seal via the second pipeline, absorbing the heat generated by the seal's sealing surface. Because the pressure of the high-pressure process medium is greater than the pressure of the process medium inside the pump (22 kg), the small pressure difference allows the high-pressure process medium to carry heat into the pump, mixing with the existing process medium and thus cooling the pump's mechanical seal.

[0029] Example 2

[0030] An online cleaning method for a pump mechanical seal, employing the pump mechanical seal cooling structure of Example 1, includes the following steps:

[0031] 1) Close the first normally open valve a, close the second normally open valve b, open the drain valve c, and then open the second normally open valve b again, so that there is a huge pressure difference between the pump mechanical seal cooling chamber and the drain valve, which is about 21 kg. Under the action of the high differential pressure, the process medium in the pump is quickly discharged through the pump mechanical seal cooling chamber, the second pipeline 2, and the drain valve c. The opening time of the drain valve is usually 5-10 seconds.

[0032] 2) Close the second normally open valve b, then close the drain valve c, and open the first normally open valve a and the second normally open valve b to complete the online cleaning of the pump mechanical seal.

Claims

1. An on-line cleaning method for a mechanical seal for a pump, characterized by: The pump seal cooling structure comprises a first pipeline (1), a second pipeline (2) and a cooler (3), the upstream end of the first pipeline (1) is connected with the pump outlet, the downstream end is connected with the process medium passage inlet of the cooler (3), a first normally open valve (a) is arranged on the first pipeline (1), the upstream end of the second pipeline (2) is connected with the process medium passage outlet of the cooler (3), the downstream end is connected with the cooling cavity of the pump seal, a guide valve (c) is arranged on the second pipeline (2), a second normally open valve (b) is arranged on the second pipeline (2), the second normally open valve (b) is close to the pump seal; The online cleaning comprises the following steps: 1) after closing the first normally open valve (a), closing the second normally open valve (b), opening the guide valve (c), and then opening the second normally open valve (b), the process medium in the pump is discharged quickly through the cooling cavity of the pump seal, the second pipeline (2) and the guide valve (c), and the process medium is discharged outside, during the process of discharging the process medium outside, the sealing surface of the pump seal and the cooling cavity are efficiently flushed, and the deposited impurities are flushed out through the second pipeline and the guide valve, and the opening time of the guide valve (c) is 5-10s; 2) closing the second normally open valve (b), and then closing the guide valve (c), opening the first normally open valve (a) and the second normally open valve (b), the high-pressure process medium treated by cooling enters the cooling cavity of the pump seal through the second pipeline, absorbs the heat generated by the sealing surface of the pump seal, and under the action of a small pressure difference, the high-pressure process medium carries heat into the pump and mixes with the process medium in the pump, so that the pump seal is cooled, and the online cleaning of the pump seal is completed.

2. The in-line cleaning method of claim 1, wherein: The cooler (3) is a tube-in-tube heat exchanger, the shell side of the tube-in-tube heat exchanger is the cooling medium passage, and the tube side of the tube-in-tube heat exchanger is the process medium passage.

3. The in-line cleaning method of claim 1, wherein: The lower portion of the guide valve (c) is provided with a water bucket (4).

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