JP2005061743A - Incineration ash treating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for easily and smoothly performing incineration ash pushing-out operation. <P>SOLUTION: An incineration ash storage part 32 is arranged for receiving incineration ash dropped and supplied from an incineration input part. An incineration ash discharge part 33 is arranged in the incineration ash storage part 32. The incineration ash storage part 32 is provided with an incineration ash pushing-out device 20 for storing water for water-sealing a part between the incineration ash input part and the incineration ash discharge part 33 for freely cooling the incineration ash, and pushing out the incineration ash in the incineration ash storage part 32 to the incineration ash discharge part 33. A partition wall 12 is arranged for partitioning the inside of the incineration ash storage part 32 into a plurality of pushing-out grooves 11; pushing-out plates 21 for pushing out the incineration ash, are respectively arranged inside the pushing-out grooves 11; and a driving mechanism 24 is arranged for protruding and retreating the respective pushing-out plates in the direction of the incineration ash discharge part 33, to constitute the incineration ash pushing-out device 20. A water communicating part 13 capable of moving water is arranged over between the mutually adjacent pushing-out grooves 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides an incineration ash storage unit that receives the incinerated ash dropped from the incineration ash charging unit, an incineration ash discharge unit is provided in the incineration ash storage unit, and the incineration ash storage unit contains the incineration ash. An incineration ash extrusion device that accommodates water in a freely coolable manner so that water can be sealed between the incineration ash charging unit and the incineration ash discharge unit, and pushes out the incineration ash in the incineration ash storage unit to the incineration ash discharge unit It relates to the incinerated ash treatment apparatus provided.

In a conventional incinerator or the like, generated incineration ash is cooled by adding water, and is made into a slurry and extruded and conveyed outside the system.
The incineration ash treatment equipment accepts the incineration ash dropped from the ash discharge part of the incinerator into the incineration ash storage part through the incineration ash input part, and incinerate the slurry incineration ash by the incineration ash extrusion equipment at regular intervals. The slurry is pushed out toward the ash discharge section, and the slurry discharged out of the system is further carried out by a conveyor or the like (see Patent Documents 1 and 2).

Such an incineration ash treatment apparatus is formed in a hermetically sealed manner in order to keep the generation side of the incineration ash, such as an incinerator, and the outside of the system airtight and prevent the incineration ash from scattering. At this time, the incineration ash charging unit is provided with a pipe line standing upright, and an incineration ash storage part is provided at the lower end of the pipe, and the incineration ash storage part is provided with a diagonally upward pipe. While constituting an ash discharge part, water is accommodated in the incineration ash storage part. Then, the space between the incineration ash storage unit and the incineration ash discharge unit is water-sealed, and the incineration ash dropped to be cooled is slurried to prevent the incineration ash from being scattered. The space between the storage unit and the incinerated ash discharge unit can be maintained airtight. In addition, a vertical pipe for supplying the incinerated ash to the conveying means such as a conveyor is connected to the pipe constituting the incinerated ash discharge part from the upper end of the diagonally upward pipe.
In addition, the incineration ash storage unit is equipped with an incineration ash extrusion device, and by moving the extrusion plate provided in the incineration ash storage unit toward the incineration ash discharge unit by a drive mechanism, The slurry is extruded.

  As described above, when the extrusion plate is pushed and moved toward the incineration ash discharge part, the incineration ash accumulated in the water of the incineration ash storage part is pushed out to the incineration ash discharge part side, and the obliquely upward pipe It is pushed up along the road. At this time, the water level of the incineration ash storage unit rises with the incineration ash pushed up and is pulled down with the incineration ash extrusion device to be pulled back back. There is a risk that the airtightness between the incineration ash and the incineration ash storage part may be lost, or the water stored in the incineration ash storage part may be discharged from the incineration ash storage part more than necessary. In order to prevent such undulations of the water surface, the extrusion plate is generally formed narrower than the width from the incineration ash storage part to the incineration ash discharge part. Then, a part of the incinerated ash extruded between the inner wall of the incinerated ash storage unit and the extruded plate passes through the side of the extruded plate together with the cooling water and moves in the opposite direction to the incinerated ash discharge unit side. A path is formed that can be made. Therefore, most of the incineration ash is pushed out to the incineration ash discharge part, but part of it flows backward with the cooling water, so that the water surface of the incineration ash storage part is not greatly rippled and maintains airtightness. It plays a role in preventing water from being discharged more than necessary.

  However, when the incinerated ash that has flowed back enters the back surface of the extrusion plate, the incineration ash on the back surface side of the extrusion plate is removed when the extrusion plate is retreated from the incineration ash discharge portion side. In some cases, it is pulled back to the opposite side (hereinafter referred to as the base end side) and deposited. As a result, the push-out operation of the extruded plate cannot be performed sufficiently, and the incineration ash push-out operation cannot be performed sufficiently smoothly. In such a case, it is necessary to confirm the accumulation state of the incineration ash from the inspection opening provided on the base end side of the incineration ash storage unit, and to perform the removal work of the incineration ash accumulated by the operator, It required a lot of effort.

  Therefore, a technique has been considered in which an incineration ash discharge section is provided also on the base end side to prevent the incineration ash from being deposited and to keep the incineration ash pushing out smoothly (see Patent Document 3). .

JP 11-22949 A JP-A-9-318037 JP 2002-257319 A

  However, in order to adopt such a configuration, a sufficient space is required at the installation location of the incineration ash treatment apparatus, the structure becomes complicated and expensive, and maintenance management becomes difficult. There's a problem.

  Then, the objective of this invention exists in the point which provides the technique which enables smooth incineration ash extrusion operation easily in view of the said actual condition.

  The first characteristic configuration of the present invention for achieving the above object is to provide an incineration ash storage unit that receives the incinerated ash dropped from the incineration ash charging unit, and to provide the incineration ash discharge unit in the incineration ash storage unit. The incineration ash storage unit accommodates water so that the incineration ash can be cooled freely and can be sealed between the incineration ash charging unit and the incineration ash discharge unit, and the incineration in the incineration ash storage unit An incineration ash extrusion device that pushes out the ash to the incineration ash discharge part is provided, a partition wall that partitions the inside of the incineration ash storage part into a plurality of extrusion grooves, and an extrusion plate that pushes out the incineration ash is provided in each of the extrusion grooves. , Providing a drive mechanism for moving the respective extrusion plates in and out of the incineration ash discharge unit to constitute the incineration ash extrusion device, and allowing water to move between the adjacent extrusion grooves The point is that a part is provided.

In other words, since an incineration ash storage unit for receiving the incineration ash dropped from the incineration ash input unit is provided, for example, the incineration ash generated from an incinerator or the like is introduced by transporting to the incineration ash input unit. The incinerated ash can be dropped and supplied to the incinerated ash storage part. Moreover, since the incineration ash discharge part is provided in the incineration ash storage part, the incineration ash once stored can be discharged from the incineration ash discharge part by moving to the incineration ash discharge part.
At this time, the incineration ash storage unit contains water so that the incineration ash can be cooled freely and can be sealed between the incineration ash charging unit and the incineration ash discharge unit. The incinerated ash accommodated in the ash storage unit is cooled in contact with water, and is prevented from scattering because it is wetted and slurried in the incineration ash storage unit. When the incineration ash is made into a slurry, the incineration ash pusher can push out the incineration ash in the incineration ash storage unit to the incineration ash discharge unit.

  Here, if the partition wall which partitions the inside of the incineration ash storage part into a plurality of extrusion grooves is provided, the incineration ash dropped and supplied to the incineration ash storage part enters each of the plurality of extrusion grooves. In addition, an incineration ash extrusion device is provided in each of the extrusion grooves, each having an extrusion plate for extruding incineration ash, and a drive mechanism for moving each extrusion plate in and out toward the incineration ash discharge unit. Therefore, the incinerated ash that has entered each of the extrusion grooves is stored for each of the extrusion grooves so that the extrusion operation can be performed.

  In this state, when the incineration ash in the extrusion groove is pushed out by the extrusion plate, the incineration ash is moved in the extrusion groove in a slurry state and reaches the incineration ash discharge section. At this time, when the incineration ash moves from below the water surface to the upper surface of the water surface, even if the water surface is ruffled, provided with a water passage portion that allows water to move between the adjacent extrusion grooves, Since the undulated water moves to the adjacent extrusion groove side through the water flow section, the undulation level in the incineration ash storage section in the conventional structure is suppressed to a lower level than when extrusion operation is performed by the extrusion plate. Can do. Then, between the inner wall of the incineration ash storage part and the extrusion plate, a part of the incineration ash extruded can pass through the side of the extrusion plate and move in the opposite direction to the incineration ash discharge part side. Even if a passage is not formed, the water surface of the incineration ash storage part is not greatly swelled, the airtightness is maintained, and the incineration ash can be pushed out while suppressing excessive discharge of water. it can.

  Therefore, according to the above-described configuration, the risk of incineration ash entering the back side of the extruded plate can be reduced, and the incinerated ash is accumulated on the proximal end side of the incinerated ash storage unit, so that the operation of moving the extruded plate out and out is performed. It becomes possible to effectively prevent inconvenience that the incineration ash can not be pushed out sufficiently smoothly because the incineration ash cannot be pushed out sufficiently.

  Further, a second characteristic configuration of the present invention is the above configuration, wherein the partition wall height is set to be equal to or lower than a water level inside the incineration ash storage unit, and the partition wall upper space is formed in the water flow unit. It is in a certain point.

Generally, since incineration ash is deposited in water, it is possible to operate the incineration ash extrusion device in a state where high fluidity water that does not contain much incineration ash is stored above the incineration ash storage unit. It becomes easy. Therefore, if a water flow section is provided in the upper space, highly fluid water that does not contain much incineration ash can be moved between the extruding grooves, so that the wave propagation to the adjacent extruding grooves is smooth. Therefore, it contributes to the prevention of ripples in the incineration ash storage part.
For example, in the case where the incineration ash is generated from an incinerator for municipal waste, etc., the incineration ash has a relatively large lump or long object such as a metal can or a wire mesh (hereinafter simply referred to as a lump). It may be thrown into the incineration ash storage part. When such a lump has been thrown into the incineration ash storage section and the lump has been placed on the partition wall, even if the extruding plate is moved back and forth, In some cases, the lump cannot be extruded toward the incineration ash discharge part, and the extrusion conveyance efficiency decreases, or the incineration ash forms a bridge starting from the lump and the incineration ash charging part is There is a risk of blockage.
However, according to the above-described configuration, since the partition wall height is set to be equal to or lower than the water level inside the incineration ash storage unit, the entire water surface of the incineration ash storage unit becomes the water flow unit, and the water flow unit is Can be set large. Moreover, even if the lump has got on the partition wall, the lump is located below the water surface, so even if the extruding plate cannot directly extrude the lump. The lump can be easily moved from the partition wall due to the movement of water accompanying the moving out, and the inconvenience caused by the lump remaining on the partition wall can be easily eliminated. become.

In addition to the above configuration, the third characteristic configuration of the present invention includes:
The partition wall extends over the incineration ash discharge part to form an extrusion groove, and the partition wall has a gap between the upper wall part of the incineration ash discharge part and the partition wall. In the point.

When the incineration ash in the extrusion groove is extruded by the extrusion plate, the extrusion load corresponds to the total weight of the incineration ash to be extruded, not only the incineration ash in the extrusion groove in the incineration ash storage unit, The weight of the incineration ash accumulated in the incineration ash discharge part also affects the extrusion load.
Here, if the incineration ash extruded from the plurality of extrusion grooves is configured to merge in the incineration ash discharge unit, the extruded incineration ash slurry is integrated in the incineration ash discharge unit. The extrusion operation is sequentially performed for each of the extrusion grooves. Then, the force required for incineration ash extrusion in each extrusion groove requires the force necessary to push out the entire amount of incineration ash in the incineration ash discharge section for any of the extrusion plates, and drives each extrusion plate. It is necessary to set a large driving force necessary for the operation. Therefore, there is a possibility that the drive mechanism in the incineration ash extrusion device must be made large, or the operation efficiency of the drive mechanism may be lowered.

  On the other hand, according to the third characteristic configuration, the incineration ash pushed out to the incineration ash discharge part is pushed out into the extruding groove divided by the partition wall, so that each other The incineration ash extruded from the adjacent extrusion groove to the incineration ash discharge part is less likely to merge and is less likely to be integrated. Therefore, when the extrusion plate extrudes the incineration ash, only the amount of incineration ash in the extrusion groove becomes a load, and the incineration ash can be extruded with a small load.

  In addition, since a gap is provided between the upper wall portion of the incineration ash discharge portion and the partition wall, the incineration ash storage is performed while a lump such as the metal can and the wire net is on the partition wall. Even if pushed out to the incineration ash discharge part, the lump will be transferred to the end of the incineration ash discharge part through the gap, and the lump will interfere with the incineration ash treatment. This can prevent the cause.

In addition to the above configuration, the fourth characteristic configuration of the present invention includes:
Of the plurality of extrusion plates of the plurality of incineration ash extrusion apparatuses, the extrusion volume of the extrusion plate that is pushed out to the incineration ash discharge unit by the drive mechanism, and the pulling of the extrusion plate that is retreated from the incineration ash discharge unit A drive control unit for driving the drive mechanism is provided so that the return volumes are equal.

When the extruded plate is extruded and moved at a predetermined speed, the movement trajectory per unit time of the extruded plate occupies the extruded volume of the extruded plate. Conversely, when the extruded plate is retired, the movement trajectory per unit time of the extruded plate occupies the retired volume of the extruded plate.
Therefore, the amount of incineration ash (extrusion volume) that is pushed and moved to the incineration ash discharge part side by the drive mechanism and the water that is formed when the extrusion plate is retreated from the incineration ash discharge part is accommodated. When the drive mechanism is driven so that the possible amount of space (retraction volume) is equal, the volume in the incineration ash storage section where the incineration ash is pushed out and reduced as the incineration ash is pushed out, and the retraction of the extrusion plate The volume in the incineration ash storage portion that increases by movement coincides with the water moved toward the water surface by pushing out the incineration ash by the retraction movement of the extrusion plate through the water passage portion. It is guided toward the formed space. Therefore, the extruding plate can be gently moved in and out without causing the water surface to wave with the rapid volume change of the incinerated ash storage part.

Embodiments of the garbage incineration facility of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the garbage incineration facility includes a garbage pit 100 that stores garbage collected from the garbage transport vehicle 101, and a garbage incinerator 200 that incinerates the garbage stored in the garbage pit 100. In addition, the garbage incinerator 200 is provided with an incineration ash treatment apparatus 300 for treating the garbage incineration ash generated from each place of the garbage incinerator.

In the space above the garbage pit 100, a crane device 102 for introducing garbage from the garbage pit 100 to the garbage hopper 400 is provided, and the garbage thrown by the crane device 102 is hydraulically driven provided at the lower part of the garbage hopper 400. It is put into the furnace by an extruding mechanism 500 of the type.
The waste incinerator 200 includes a stoker mechanism 600 that dries, burns, and incinerates while transporting the waste introduced by the push-out mechanism 500, and constitutes a combustion section. A blower 701 is provided below the stoker mechanism 600. A primary combustion air supply mechanism 700 having a wind box 702 for supplying the air is provided to promote combustion, and the ashed residual is conveyed to the incineration ash treatment apparatus 300.
In the upper space of the stoker mechanism 600, a flue 800 having a secondary combustion air supply mechanism 801 and a waste heat boiler 802 is formed, and an exhaust gas treatment device 803 provided downstream of the flue 800. The exhaust gas purified by is exhausted from the chimney.

  As shown in FIG. 1, the incineration ash treatment apparatus 300 is made up of residuals generated from the combustion section, dust that has entered the air supply mechanism 700 to the combustion section, dust collected from the exhaust gas treatment apparatus 803 and the like. The incineration ash charging unit 31 for dropping and injecting the incinerated ash is provided upright, and an incineration ash storage unit 32 is provided at the lower end of the pipeline, and the incineration ash storage unit 32 is inclined upward. A pipeline is provided to constitute the incineration ash discharge unit 33, and water is stored in the incineration ash storage unit. Thereby, the space between the incinerated ash storage unit 32 and the incinerated ash discharge unit 33 is sealed with water, and the incinerated ash dropped and supplied is cooled and slurried, thereby preventing scattering of the incinerated ash, The space between the incineration ash storage unit 32 and the incineration ash discharge unit 33 can be maintained airtight. Further, the pipe constituting the incineration ash discharge part 33 is continuously provided with a vertical pipe for dropping the incineration ash from the upper end of the obliquely upward pipe to the conveying means 34 such as a conveyor. The incinerated ash dropped and supplied to the conveyor is conveyed to the ash pit 35 and stored.

  As shown in FIGS. 2 to 4, the incineration ash storage part 32 is provided with a partition wall 12 that partitions the inside thereof into a pair of extrusion grooves 11, and the extrusion ash is extruded into each of the extrusion grooves 11. A board 21 is provided. The pusher plate 21 is provided with a drive mechanism such as a hydraulic cylinder 24 via a drive arm 23, and each pusher plate 21 is incinerated from the drive chamber 36 side provided on the base end side of the incineration ash reservoir 32. The incineration ash extrusion device 20 is configured to move in and out in the direction toward the ash discharge unit 33.

As shown in FIGS. 1 and 5, the height of the partition wall 12 inside the incineration ash storage unit 32 is a water seal height (water level) between the incineration ash storage unit 32 and the incineration ash discharge unit 33. ), And the upper space of the partition wall 12 is formed in a water passage portion 13 that allows water to move between the extruding grooves 11 and 11 adjacent to each other.
Further, as shown in FIG. 6, the partition wall 12 extends over the incineration ash discharge part 33, and forms an extrusion groove 11 over the incineration ash discharge part 33. The partition wall 12 in the incineration ash discharge part 33 is provided so as to form a gap 15 between the upper wall part 14 of the incineration ash discharge part 33 and the partition wall 12. Even if a lump such as a can or a wire net is pushed out, the lump is set so as not to be clogged. The partition wall 12 extends to the upper side of the water surface of the incineration ash storage part 32 so as not to form a gap 15 between the incineration ash storage part 32 and the peripheral wall on the drive chamber 36 side. In addition, it is set so that water does not flow from the incineration ash storage unit 32 to the drive chamber 36 side through the water flow unit 13.

As shown in FIGS. 4 and 7, the extrusion plate 21 has an extrusion surface 21 a that covers the entire width of the one extrusion groove 11, and the incineration ash storage in the extrusion groove 11 is performed by the incineration ash extrusion device 20. When the incineration ash accumulated in the extrusion groove 11 is moved from the incineration ash storage unit 32 to the incineration when being pushed and moved from the side end (base end side) of the portion 32 toward the incineration ash discharge unit 33 side (front end side). It can be pushed and moved to the ash discharge part 33 side. Further, the extrusion plate 21 is fixed to a holding member 22 such as H-shaped steel, and a cover member 25 covering the upper surface side is connected to the holding member 22, and incineration ash is formed on the back surface side of the extrusion surface 21 a of the extrusion plate 21. It is formed so that it is difficult to enter. Further, an incineration ash auxiliary pushing surface 25a is also formed on the upper surface portion of the cover member 25 so as to push out the incinerated ash that has flowed backward to the upper surface side of the cover member 25 as much as possible.
The bottom surface of the incineration ash storage section 32 is curved in a direction from the base end side to the front end side so that the incineration ash settles and naturally collects at the bottom, and the extruded plate 21 is smooth. It is shaped so that it can be pushed out while sliding up and scooping up the incineration ash.

  The incineration ash extrusion device 20 is configured to be able to individually drive the extrusion plates 21 provided in the respective extrusion grooves 11 as shown in FIGS. 3, 7, and 8. The extrusion volume V of the extrusion plate 21 that is pushed out and moved to the incineration ash discharge part 14 side in the extrusion groove 11 of the other, and the extrusion plate 21 that is retreated from the incineration ash discharge part 14 in the other extrusion groove 11. A drive control unit 26 for driving the incineration ash extrusion device 20 is provided so that the retraction volumes V are equal, so that the water surface of the incineration ash storage unit 32 is not so rippled even when the extrusion plate 21 is driven. Drive control. Normally, one extrusion plate 21 is extruded over about 3 minutes and the other extrusion plate 21 is retired, then the reverse operation is performed over about 3 minutes, and incineration is performed for about 3 minutes. The incineration ash extruding device 20 is driven and controlled to repeat these operations again after waiting for the ash to be charged.

  The drive chamber 36 has a water supply unit 61 for supplying water that is absorbed by the incinerated ash to be transported and reduced by being taken out of the system from the incinerated ash storage unit 32, and water. A drainage unit 62 is provided for discharging surplus water accompanying the rise of the water level in the incineration ash storage unit 32 due to replenishment or incineration ash injection. As a result, the water surface height is kept constant and it is difficult for the water surface to ripple, so that the water-sealed state between the incineration ash storage part 32 and the incineration ash discharge part 33 is kept stable.

  In addition, although the example which provided the said extrusion groove | channel 11 in the above-mentioned structure was shown, it is also possible to provide not only this but three or more extrusion grooves 11 and to comprise. For example, when three extrusion grooves 11 are formed, the width of the extrusion groove 11 formed on both sides is about ½ of the extrusion groove 11 formed in the center, and the sum of the areas of the extrusion plates 21 on both sides is the center. By forming it equal to the area of the extrusion plate 21, the extrusion volume V of the extrusion plate 21 moved to the incineration ash discharge section 14 side in the central extrusion groove 11 and the extrusion grooves 11 on both sides are formed. The incineration ash extruding device 20 can be easily driven so that the retraction volume V of the extruding plate 21 retreated from the incineration ash discharge unit 14 is equal, and incineration is mainly performed in the central extrusion groove 11. The role sharing can be clarified by extruding ash and controlling the undulations of the water surface with the extrusion grooves 11 on both sides.

According to such an incineration ash treatment device, since smooth incineration ash extrusion operation can be performed easily, ash treatment of an incinerator or the like can be performed efficiently, and labor required for maintenance and inspection can be greatly reduced. .
Note that such an incineration ash treatment apparatus can be used not only in a stoker type incinerator but also in various ash treatment facilities.

Schematic diagram of incinerator Vertical side view of incineration ash treatment equipment Cross-sectional plan view of incineration ash treatment equipment Notched perspective view of incineration ash treatment equipment AA sectional view of FIG. 2 in the incineration ash storage part of the incineration ash treatment apparatus BB sectional view of FIG. 2 in the incineration ash discharge part of the incineration ash treatment apparatus Longitudinal side view showing drive state of incineration ash extrusion device Cross-sectional plan view showing the drive state of the incineration ash extrusion device

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Extrusion groove 12 Partition wall 13 Water flow part 20 Incineration ash extrusion apparatus 21 Extrusion board 23 Drive arm 24 Hydraulic cylinder 25 Cover member 26 Drive control part 31 Incineration ash input part 32 Incineration ash storage part 33 Incineration ash discharge part 34 Conveyance means 35 Ash pit 36 drive room

Claims (4)

An incineration ash storage unit that accepts the incineration ash dropped from the incineration ash input unit,
While providing an incineration ash discharge part in the incineration ash storage part,
The incineration ash storage unit contains water so that the incineration ash can be cooled freely and can be sealed between the incineration ash input unit and the incineration ash discharge unit,
An incineration ash treatment device provided with an incineration ash extrusion device for extruding incineration ash in the incineration ash storage unit to an incineration ash discharge unit,
While providing a partition wall that partitions the inside of the incineration ash storage part into a plurality of extrusion grooves,
An extrusion plate for extruding incineration ash is provided inside each of the extrusion grooves,
Provided with a drive mechanism for moving each extrusion plate in and out of the incineration ash discharge part,
Configure the incineration ash extrusion device,
An incineration ash treatment apparatus provided with a water passing portion that allows water to move between the extrusion grooves adjacent to each other.   The incineration ash treatment apparatus according to claim 1, wherein the partition wall height is set to be equal to or lower than a water level inside the incineration ash storage unit, and the partition wall upper space is formed in the water flow unit.   The partition wall extends over the incineration ash discharge part to form an extrusion groove, and the partition wall has a gap between the upper wall part of the incineration ash discharge part and the partition wall. The incineration ash treatment apparatus according to claim 2.   Of the plurality of extrusion plates of the plurality of incineration ash extrusion apparatuses, the extrusion volume of the extrusion plate that is pushed out to the incineration ash discharge unit by the drive mechanism, and the pulling of the extrusion plate that is retreated from the incineration ash discharge unit The incineration ash treatment apparatus according to any one of claims 1 to 3, further comprising a drive control unit that drives the drive mechanism so that the return volumes are equal.

Images