JP2002257069A - Method and device for automatically controlling seal water amount of wet type vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a function of a vacuum pump, secure maintenance and stabilize quality of a sucked object by adequately keeping a seal water amount of the vacuum pump for dewatering a running wetting matter, and to prevent over load phenomenon in restart by setting the seal water amount remaining in a casing during stop of the pump to only an amount required for the restart. SOLUTION: Seal water discharged from the vacuum pump is made to flow into a seal box forming a triangle weir in a discharging part, a duct terminal is inserted into water of the box, short circuit between a suction system and the atmosphere is broken, height of an overflow level of the triangle weir is matched to a suitable seal water amount, liquid level adjustment of the box is performed by controlling a supply amount of refilled water, the supply of the refilled water corresponding to the dewatering amount from the sucked object is allowed, the supply of the refilled water is automatically stopped simultaneously with the stop of the pump, filling with water in the casing or a connecting duct is prevented, and the over load phenomenon in restarting the pump is solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the operation of a vacuum pump for dewatering a continuously running wet material such as a wet running paper layer on a wire of a paper machine in the papermaking industry and a wet running felt in a press section. The present invention relates to a technique relating to appropriate management of the amount of seal water required for the above.

[0002]

2. Description of the Related Art Conventionally, a wet vacuum pump has been used to dehydrate water-permeable objects that contain a large amount of moisture when traveling continuously, such as wet paper webs and wet press felts on running wires in paper machines. Have been. The main body of this vacuum pump is composed of a casing and a rotating impeller. The rotation of the impeller causes the inside of the casing to be at an extremely low pressure close to vacuum, and sucks air and moisture from the suction target. In order to maintain extremely low pressure, the gap between the casing and the impeller must always be sealed with a water film (seal water). However, the seal water must be constantly replenished because it is discharged out of the casing together with the exhaust air. . The amount of seal water per unit time is determined for each pump depending on the structure of the vacuum pump, the amount of exhaust, etc.If the amount is small, a water film is not formed, and if the amount is excessive, the pump becomes overloaded and becomes overloaded. Heats up and eventually breaks down,
Seal water volume must be strictly observed.

[0003] However, the total seal water amount is the sum of the amount of dewatering from the suction target and the amount of makeup water supplied separately.
The amount of make-up water can be measured by a flow meter, but the amount dewatered from the suction target cannot be measured because it is mixed with air. Therefore, it becomes meaningless to measure the amount of makeup water. Furthermore, the amount of dehydration from the suction target is usually not always constant, and when the amount occupies a relatively large amount in the sealing water, the total sealing water amount changes greatly, and the pressure in the casing changes pulsatingly. . As a result, the mechanical load not only changes in pulsation, but also greatly changes the amount of dehydration of the suction target, which causes uneven water in the paper layer of the paper machine, which is a fatal obstacle to product management of the papermaking paper. Becomes

Conventionally, as described above, since it is not possible to measure the total seal water amount, it is determined based on the suction sound of the vacuum pump, the electric current value of the electric motor, the outflow state of the final drain amount visually, and the like. It was adjusted manually by the operator. However, in general, in order to give priority to ensuring the quality of papermaking products, make up excess water at the expense of mechanical load and life, and reduce the ratio of dewatering amount of suction target to total sealing water amount. In addition, the pulsation change of the suction force of the vacuum pump is suppressed as much as possible. Also, when the vacuum pump stops, if the supply of makeup water is not stopped at the same time, the casing and the connected intake and exhaust pipes will be filled,
At the time of restarting, a complete water pump phenomenon occurs and an excessive load is instantaneously applied, which causes a failure of the vacuum pump and a burnout accident of the electric motor. Most of the actual failure cases are caused by this. However, in general, stopping the vacuum pump means stopping all the related production processes, and it often requires complicated work to respond to other main parts that require urgency or equipment stoppage, At present, the stoppage of the replenishment water of the vacuum pump, which is an auxiliary mechanical component in the production process, tends to be delayed.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to automatically maintain the total amount of sealing water of a vacuum pump at all times and to automatically stop the supply of make-up water simultaneously with the stop of the vacuum pump in combination with the mechanism. It is intended for.

[0006]

Means for Solving the Problems The whole sealing water of the wet vacuum pump is caused to flow into a seal box having a triangular weir as a drain, and the level of the water is detected to adjust the amount of water supplied to the vacuum pump. On the other hand, the mechanism that controls the total seal water volume properly and combines the start / stop circuit of the vacuum pump motor and the signal circuit that opens and closes the control valve for the replenishment seal water provides safe operation for vacuum pump maintenance and its suction operation. The method for automatically controlling the sealing water amount of a wet vacuum pump, characterized by stabilizing the quality of the product to be suctioned by stabilizing the suction target, and draining all the sealing water of the wet vacuum pump from the triangular weir It is designed to flow into a sealed seal box, and by detecting the water level, the amount of water supplied to the vacuum pump is adjusted and the total seal water amount is properly controlled. On the other hand, a mechanism that combines the start / stop circuit of the electric motor of the vacuum pump and the signal circuit for opening and closing the control valve of the replenishment seal water is used. The structure of the automatic control device for the sealing water amount of the wet vacuum pump is characterized in that the quality of the product is stably maintained.

[0007]

DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 (a) and 1 (b) [FIG.
(A), a cross-sectional view taken along the line II-II '], air and moisture sucked by a vacuum pump (1) from a suction target (A), for example, a wet paper web, while traveling, are subjected to vacuum from a suction pipe (2). It is sent into the casing of the pump (1) and is pressurized by the impeller to form a gas-water mixture, which flows from the exhaust pipe (3) to the silencer / gas-water separator (4), where it is converted into air and moisture. The separated, most of the air is exhausted upwards, while the separated water, while containing some air, has a drain pipe (5).
To the seal box (6), where the terminal of the drain pipe (5) is inserted into the water (Wa) to cut off the short circuit between the suction system and the atmosphere. The seal box (6) is divided into a storage chamber (8) and an outflow chamber (9) by a partition plate (7).
As a result, the waving of the liquid surface is eliminated, and the liquid is drained from the outflow chamber (9) to the outside beyond the triangular weir (10) [the angle is 90 degrees].

A liquid level detector (1) is provided in the seal box (6).
1) is attached, the liquid level is converted into a signal and sent to a controller for adjusting air (12), and the opening of the make-up water control valve (13) is adjusted according to the liquid level signal, The amount of makeup water (W) supplied into the vacuum pump (1) is automatically adjusted appropriately.
An open / close signal circuit (C) is connected to the controller (12) from a switch (15) of an electric motor (14) of the vacuum pump (1).
3) is quickly and completely closed to stop the supply of makeup water (W). When the vacuum pump (1) is started, the fully closed signal of the control valve (13) is released, and the control circuit of the controller (12) is restored. In the present invention, the total amount of seal water discharged from the vacuum pump (1) is measured without being affected by the air in the exhaust, and is controlled to control the amount of make-up water (W) appropriately. I try to make it. That is, the total seal water amount is the dewatering amount from the suction target (A) and the makeup water (W).
Therefore, even if the amount of dehydration from the suction target (A) is unknown, it is possible to control the amount of makeup water (W) if the total sealing water amount can be grasped. As a means for measuring the amount of sealing water, the outflow portion of the sealing box (6) is formed as a triangular weir (10).

A vacuum pump (1) is provided outside the triangular weir (10).
An index (16) that can be easily visually identified is attached to a water height position that matches the amount of seal water per unit time that is suitable for the function of (1). The seal water has already been released from the storage chamber (8) of the seal box (6), so the triangular weir (10)
Is only the seal water, and the appropriate quantity can be easily visually identified by the index (16), so that a particularly expensive indicator is not required. By properly controlling the overflow water level of the triangular weir (10), that is, the liquid level of the seal box (6), the amount of seal water can be controlled without being affected by air in the exhaust gas. As a result, the amount of water obtained by subtracting the amount of dehydration from the suction target (A) from the total amount of seal water is appropriately replenished from the control valve (13) of the make-up water (W). At the same time as the vacuum pump is stopped, the control valve (13) is fully closed, and the supply of make-up water (W) is completely stopped. Therefore, only the amount of sealing water necessary for restarting remains in the casing of the vacuum pump (1). Therefore, trouble occurrence due to overload at the time of restarting the vacuum pump (1) is eliminated. At the time of restarting the vacuum pump, the level control function of the controller (12) is restored by the start signal.

[0010]

According to the present invention, the function of the vacuum pump can be maintained, the mechanical maintenance can be ensured, and the amount of seal water required for the operation of the vacuum pump for dewatering the running wet matter can be automatically and appropriately maintained. It is possible to stabilize the quality of the suction target, which is the purpose of use of the vacuum pump. In addition, when the vacuum pump is stopped, the supply of make-up water is automatically stopped. This saves the labor required for the supply. Only an appropriate amount of sealing water remains in the casing, which causes an excessive load phenomenon at restart. Can be eliminated.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall state of a seal water automatic control device of a wet vacuum pump according to the present invention.

[Explanation of symbols]

 (1) Vacuum pump (2) Suction pipe (3) Exhaust pipe (4) Silencer and steam separator (5) Drain pipe (6) Seal box (7) Partition plate (8) Storage chamber (9) Outflow chamber ( 10) Triangular weir (11) Liquid level detector (12) Controller (13) Control valve (14) Motor (15) Switch (16) Sign (A) Traveling suction target (C) Opening / closing signal circuit (W) Makeup water (Wa) Underwater

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F04C 29/10 331 F04C 29/10 331A 331B F term (reference) 3H029 AA07 AA18 AA22 AB06 BB09 BB10 BB12 BB16 BB33 BB42 BB50 BB54 BB60 CC19 CC28 CC32 CC48 CC55 CC65 CC66 3H045 AA05 AA26 BA24 BA33 BA42 BA43 CA15 DA02 DA11 DA43 DA45 EA14 EA27 EA34 EA42 EA43

Claims (2)

[Claims] 1. The entire sealing water of a wet vacuum pump is caused to flow into a seal box having a triangular weir as a drain, and by detecting the level of the water, the amount of water supplied to the vacuum pump is adjusted to reduce the total sealing water amount. Controlling the vacuum pump motor stably and maintaining the safe operation of the vacuum pump and stabilizing the suction by using a mechanism that combines the start / stop circuit of the motor of the vacuum pump and the signal circuit that opens and closes the control valve for the replenishment seal water The method for automatically controlling the seal water amount of a wet vacuum pump, wherein the quality of a product to be suctioned is stably maintained by using the method. 2. A structure in which all sealing water of a wet vacuum pump flows into a seal box having a triangular weir as a drain port.
By detecting the water level, the amount of water supplied to the vacuum pump is adjusted to properly control the total seal water amount,
A mechanism combining a start / stop circuit for the motor of the vacuum pump and a signal circuit for opening and closing the control valve for the replenishment seal water,
An automatic control system for sealing water amount of a wet vacuum pump, characterized by stably maintaining the quality of a product to be suctioned by stabilizing the suction operation and the safe operation in maintenance of the vacuum pump.