JPH03181348A - Method for cleaning separation plate-type centrifugal separator - Google Patents

Abstract

PURPOSE:To inexpensively enhance the cleaning effect by easy technical method by switching a high-flow-rate cleaning in which a cleaning soln. discharged from a water outlet is directly returned to a raw liq. inlet and a low-flow-rate cleaning in which the cleaning soln. is circulated between a centrifugal separator and a cleaning soln. tank. CONSTITUTION:The cleaning soln. in the cleaning soln. tank 5 is injected into the raw liq. inlet 2 of a centrifugal separator 1 by a feed pump 6, and the cleaning soln. discharged from the oil outlet 3 and water outlet 4 of the separator 1 is returned to the tank 5 through the pipeline of the cleaning device. The cleaning soln. discharged from the water outlet 4 is directly returned to the raw liq. inlet 2 by a bearing disk pump 20 in the separator 1 through another pipeline. A high-flow-rate cleaning in which the cleaning soln. discharged from the water outlet 4 is directly returned to the raw liq. inlet 2 and a low- flow-rate cleaning in which the cleaning soln. is circulated between the separator 1 and the tank 5 are switched to each other. Consequently, the cleaning effect is inexpensively enhanced by easy technical method.

Description

Detailed Description of the Invention A9.Objective of the Invention [Field of Industrial Application] This invention relates to a separating plate type centrifuge (hereinafter simply referred to as a centrifugal separator) in which a large number of separating plates are provided at intervals in a rotating body. This relates to a method for cleaning and removing harmful substances such as sludge (insoluble) adhering to the surface of the internal parts of the rotating body by circulating a cleaning liquid through the rotating body of the rotating body.

[Conventional technology]

Separating plate centrifuges are used to clean fuel oil and lubricating oil for marine and land-based diesel engines. This centrifugal separator is also equipped with a mechanism to discharge separated sludge, but when used for a long time, the separated sludge is not completely discharged and accumulates on the surface of the separating plate and internal parts of the rotating body. come.

Therefore, it becomes necessary to clean the centrifuge.

Conventionally, centrifugal separators have been cleaned in the following manner using a cleaning device shown in FIG.

The cleaning liquid is supplied from the cleaning liquid tank 5 to the raw liquid inlet 2 of the centrifugal separator 1 via the liquid sending pump 6 and the flow rate control valve 8, and is returned to the cleaning liquid tank 5 through the oil outlet 3 and water outlet 4 of the centrifugal separator 1. It will be done. That is, the cleaning liquid circulates from the cleaning liquid tank 5 to the centrifuge I and then through the cleaning liquid tank 5 to clean the centrifuge I. Note that a control valve 14 is provided in the middle of the flow path from the water outlet 4 to the cleaning liquid tank 5.

The circulation amount of the cleaning liquid is determined by the capacity of the liquid pump 6, and in order to sufficiently clean the dirt inside the rotating body, a large capacity liquid pump 6 is required, but this is disadvantageous from the economical point of view of the cleaning device. Therefore, in reality, a low-capacity liquid feeding pump 6 is used.

[Problem to be solved by the invention]

In conventional centrifuge cleaning, in which cleaning is performed by circulating cleaning liquid between the centrifuge 1 and the cleaning group tank 5 using a liquid sending pump 6 with a low volume Q, the control valve 14 on the water outlet 4 side is closed. By squeezing the flow, the cleaning liquid is also discharged to the oil outlet 3 side due to the effect of flow resistance, but this effect cannot be obtained because the flow rate is small, and in most cases, the entire amount of cleaning liquid is discharged from the water outlet 4. The oil was discharged, and the central part inside the rotor and the oil outlet 3 side could not be cleaned. At the same time, there is a drawback that the heavily contaminated water outlet 4 side passage parts cannot be sufficiently cleaned due to insufficient flow rate.

The present invention provides a cleaning method that improves the cleaning effect in an economically inexpensive and technically easy method when cleaning sludge that adheres to and accumulates on the surface of a separator plate and internal parts of a rotating body using a cleaning liquid. The purpose is to

a1 Structure of the Invention [Means for Solving the Problems] In order to achieve the above object, in the method for cleaning a separating plate centrifuge of the present invention, the cleaning liquid in the cleaning liquid tank 5 is transferred to the centrifuge by the liquid feeding pump 6. The cleaning liquid injected into the raw solution inlet 2 of the centrifuge 1 and discharged from the oil outlet 3 and water outlet 4 of the centrifuge 1 is returned to the cleaning liquid tank 5, and the cleaning liquid discharged from the water outlet 4 is transferred to the centrifugal separator. Using a cleaning device having a piping system that returns the cleaning liquid directly to the raw solution inlet 2 by an internal pairing disk pump 20, high-flow cleaning is performed in which the cleaning liquid discharged from the water outlet 4 is returned directly to the raw solution inlet 2, and a centrifuge 1 is used. This is to switch to low flow rate cleaning in which the cleaning liquid is circulated between the cleaning liquid tank 5 and the cleaning liquid tank 5.

[For production]

In the cleaning method for the separator plate type centrifugal separator configured as described above, in the first high flow rate cleaning, the cleaning liquid is sent from the cleaning liquid tank 5 to the centrifugal separator 1 by the liquid sending pump 6, and the oil outlet 3 and The cleaning liquid discharged from the water outlet 4 is directly returned to the stock solution inlet 2 by a pairing disk pump 20 inside the centrifugal separator 1 . In the subsequent low flow rate cleaning, the cleaning liquid is sent from the cleaning liquid tank 5 to the centrifugal separator 1 by the liquid sending pump 6, discharged from the water outlet 4, and circulated between the centrifugal separator 1 and the cleaning liquid tank 5. At this time, no cleaning liquid is discharged from the oil outlet 3.

〔Example〕

An example of a cleaning device used in the cleaning method of the present invention will be explained with reference to FIG.

1 is a centrifugal separator, and 5 is a washing liquid tank. A liquid feed pipe 9 is provided between the cleaning liquid tank 5 and the stock liquid inlet 2 of the centrifugal separator. A liquid feeding pump 6, a check valve 7, a cleaning liquid inlet branch pipe I11 and a flow rate adjustment valve 8 are attached to the liquid feeding pipe 9 in this order from the cleaning tank 5. The oil outlet 3 on the outlet side of the centrifugal separator 1 is provided with an oil outlet pipe 13 for returning to the cleaning liquid tank 5, and the water outlet 4 is provided with a water outlet pipe 18. A control valve 14 and a three-way control valve 17 are attached to the water outlet pipe 18 in order from the water outlet 4. A circulation pipe 16 is connected from the three-way control valve 17 to the liquid supply pipe 9 between the flow rate adjustment valve 8 and the stock solution inlet 2. The three-way control valve 17 is connected to the circulation pipe 16 side and the cleaning liquid tank 5. This is provided to arbitrarily switch the flow path of the cleaning liquid to the cleaning liquid tank return pipe 15 side. Note that instead of the three-way control valve 17, an on-off valve may be provided in each of the cleaning liquid tank return pipe 15 and the circulation pipe 16.

The cleaning liquid supplied to the centrifugal separator 1 by the liquid sending pump 6 and discharged from the oil outlet 3 is returned to the cleaning liquid tank 5, and the cleaning liquid discharged from the water outlet 4 is supplied to the centrifugal separator 1 by the three-way control valve 17.
As a result, the line is switched to the line returning to the cleaning liquid tank 5 and the line returning to the liquid feeding pipe 9, thereby configuring a circulation system.

Cleaning the centrifuge l using such a cleaning device is as follows:
Do it as follows.

First perform a high flow wash.

First, an appropriate amount of cleaning liquid is put into the cleaning liquid tank 5. The three-way control valve 17 of the water outlet pipe 18 is set on the circulation pipe 16 side. Further, the flow rate of the liquid feeding pump 6 is set to a low flow rate by the flow rate control valve 8 assuming low flow rate cleaning. The centrifugal separator 1 is brought into a steady state of operation, the liquid feed pump 6 is started, and cleaning is started. The cleaning liquid filled in the rotating body is discharged from the water outlet 4, passes through the water outlet pipe 18, the three-way control valve 17, and the circulation pipe 16, returns to the liquid supply pipe 9, and enters the centrifuge 1 again from the stock solution inlet 2. Flows through a high flow circulation line. The circulation amount of the cleaning liquid at this time utilizes the ability of the pairing disk pump 20 installed in the centrifugal separator 1, and is independent of the flow rate of the liquid feeding pump 6 determined by the flow rate control valve 8. The flow rate of the pairing disk pump 20 has a pressure corresponding to the throttling pressure of the liquid feeding pump 6. Normally, the pairing disk pump 20 has performance commensurate with the capacity of the centrifugal separator l, and by setting the throttling pressure of the liquid feeding pump 6, even a liquid feeding pump 6 with a small capacity can be used for high flow rate circulation lines. The flow rate of the cleaning liquid when set to is a high flow rate close to the critical flow rate of the centrifuge l.

At this time, depending on the conditions of the specific gravity plate 22, cleaning liquid may not be discharged from the oil outlet 3 simply by increasing the flow rate.In that case, by squeezing the control valve 14 of the water outlet pipe 18, a small amount of cleaning liquid can be washed into the oil outlet 3. Acid can be discharged. The cleaning liquid discharged from the oil outlet 3 to the oil outlet pipe 13 is returned to the cleaning liquid tank 5, and its dispensing liquid is replenished, thereby maintaining high flow rate cleaning.

After performing this high flow rate cleaning for about 30 to 45 minutes, the three-way control valve 17 of the water outlet pipe 18 is switched to the cleaning liquid tank return pipe 15 side, and low flow rate cleaning is performed.

That is, the cleaning liquid discharged from the water outlet 4 is returned to the cleaning liquid tank 5 through the cleaning liquid tank return pipe 15, forming a line that circulates between the cleaning liquid tank 5 and the centrifugal separator 1. The circulating amount of the cleaning liquid at this time is determined by the capacity of the liquid feeding pump 6 set by the flow rate adjustment valve 8, and the entire amount of the cleaning liquid is discharged from the water outlet 4. This low flow rate cleaning is approximately 30 to 60 minutes.
After about 9 times, the cleaning process is completed.

Switching of the three-way control valve 17 can be easily automated by a combination of a timer and an electric three-way valve.

When the cleaning process is completed, the liquid feed pump 6 is stopped, and the centrifugal separator 1 is operated to discharge the sludge, thereby discharging the cleaning liquid and sludge from the rotating body. Next, the inside of the rotating body is washed with fresh water. Washing water is supplied from a water sealing inlet that is a standard feature of the centrifugal separator I, or from a washing water supply valve 12 provided in the middle of the liquid feed pipe 9 of the washing device. After filling the rotating body with cleaning water, the sludge discharge operation is performed. This is repeated 2 to 3 times to complete the water washing process.

In this way, in this invention, two-stage cleaning of high flow rate cleaning and low flow rate cleaning is performed in order to enhance the cleaning effect. Explain the necessity.

Generally, when cleaning sludge adhering to the surface of an object by flowing a cleaning liquid, the higher the flow rate of the cleaning liquid, the better the cleaning effect. In other words, the parts on the water outlet side can be effectively cleaned by high flow rate cleaning, and the cleaning liquid can also be easily discharged to the oil outlet 3 side by throttling the water outlet side control valve 14. Parts on the oil outlet side can also be cleaned. especially,
In order to sufficiently clean the area 23 in FIG. 2 where sludge tends to accumulate, a flow of the cleaning liquid is necessary, and it is essential to discharge the cleaning liquid to the oil outlet 4 side. In high flow cleaning,
As mentioned above, the passage parts on the water outlet side, the part 23, the central part of the rotating body, and the parts on the oil outlet side can be sufficiently cleaned, but the cleaning liquid cannot be discarded after passing through the centrifuge l only once. Since it is economical, use it recyclably. As a result, when cleaning is performed only by high flow rate cleaning, the sludge removed by cleaning the water outlet side passage parts, etc. is mixed into the cleaning liquid and is again supplied to the centrifuge l from the raw solution inlet 2 of the centrifuge l. be done. Since the cleaning liquid is also discharged to the oil outlet 3 side, it inevitably passes through the separation plate 21 and sludge re-adheres.
It is insufficient for cleaning.

Therefore, after cleaning the parts other than the separation plate 21 with high flow rate cleaning, the flow rate is switched to low flow rate ff1i=& cleaning mainly for the purpose of cleaning the separation plate 21 on which sludge has reattached.

As mentioned above, when the circulation flow rate of the cleaning liquid is set to a low flow rate,
Discharge of the cleaning liquid to the oil outlet 3 side is stopped, and the entire amount is discharged to the water outlet 4 side, so that the separation plate 21 is in an immersed state. The sludge that has reattached to the separation plate 21 due to high-flow cleaning is easily shaken off to the outside by centrifugal force because it has been washed once by the cleaning liquid and is non-sticky, and because the cleaning liquid does not flow toward the oil outlet side. . Therefore, the low flow m cleaning is performed by the separation plate 2
In addition to cleaning and removing sludge in step 1, it can also be used as a final cleaning for parts on the water outlet passage side.

In this way, by switching between high flow rate cleaning and low flow rate cleaning during the cleaning process to perform two-stage cleaning, it is now possible to clean all the parts inside the rotating body, and the cleaning effect is greater than with conventional methods. can be increased.

In addition, as a side effect of performing low-flow cleaning after high-flow cleaning,
The dirty cleaning liquid can be cleaned at the same time by high flow rate cleaning, and there is no need to filter the cleaning liquid remaining in the cleaning liquid tank 5, and it can be reused by adding new liquid. After high flow rate cleaning, a part of the cleaning liquid containing the sludge removed is discharged to the oil outlet 3 side. As mentioned above, the sludge contained therein passes through the separation plate 21.
However, most of the water is discharged to the water outlet 4 side. Since the cleaning liquid has a high flow rate, it circulates along with the flow. By switching to low flow rate cleaning, all of the cleaning liquid containing sludge is discharged to the water outlet 4 side and circulated, but since the flow rate is small, the sludge is separated and accumulated in the sludge space 24 inside the rotating body due to centrifugal force. The sludge accumulated in the sludge space portion 24 is discharged to the outside of the machine along with the cleaning liquid inside the rotating body by a discharge operation after the cleaning process is completed.

C1 Effect of the invention Since this invention is configured as explained above,
This produces the effects described below.

That is, since high flow rate cleaning and low flow rate cleaning can be combined, all parts inside the rotating body can be cleaned, and the cleaning effect can be improved compared to conventional cleaning methods.

Switching between high flow rate cleaning and low flow rate cleaning can be done simply by switching the piping of the cleaning device, and high flow rate can be obtained by using the pairing disk pump 20 originally equipped in the centrifuge. Therefore, the liquid sending pump 6 of the cleaning device
It is sufficient that the pump has the performance of a flow rate for low flow rate cleaning and a throttling pressure (usually 15 to 2 kg/c/) corresponding to the discharge pressure of the pairing disk pump. Therefore, it is possible to use a low-capacity, compact, and low-cost liquid feeding pump, which is economical, and the cleaning effect can be enhanced using a technically easy method.

Further, since the low Zlff amount cleaning is performed after the high flow rate cleaning, cleaning of the cleaning liquid contaminated by the high flow rate cleaning can be performed at the same time.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a conventional device used for cleaning centrifuges, Fig. 2 is a vertical cross-sectional view of the rotating body of a centrifuge, and Fig. 3 is a diagram of a device used for washing centrifuges according to the present invention. It is a system diagram. l Centrifuge, 2 Stock solution inlet, 3 Oil outlet, 4
Water outlet, 5 Cleaning liquid tank, 6 Liquid pump, 8
Flow control valve 8.14 Control valve, 17- Three-way control valve, 20 Pairing disc pump

Claims (1)

[Claims] 1. Piping for injecting the cleaning liquid from the cleaning liquid tank 5 into the raw liquid inlet 2 of the centrifugal separator 1 using the liquid feed pump 6, and returning the cleaning liquid discharged from the oil outlet 3 and water outlet 4 of the centrifugal separator 1 to the cleaning liquid tank 5 again. A pairing disk pump 20 inside the centrifugal separator 1 transfers the cleaning liquid discharged from the system line and the water outlet 4.
A cleaning device having a piping system that returns the cleaning liquid directly to the raw solution inlet 2 by using a high-flow cleaning method in which the cleaning liquid discharged from the water outlet 4 is returned directly to the raw liquid inlet 2, and between the centrifuge 1 and the cleaning liquid tank 5 A cleaning method for separation plate type centrifugal separators that switches to low-flow cleaning that circulates the cleaning solution.