WO2017047387A1

WO2017047387A1 - Ejector and vacuum generation device with same

Info

Publication number: WO2017047387A1
Application number: PCT/JP2016/075519
Authority: WO
Inventors: 黒田淳司
Original assignee: 株式会社テイエルブイ
Priority date: 2015-09-17
Filing date: 2016-08-31
Publication date: 2017-03-23
Also published as: EP3351805A1; EP3351805A4

Abstract

An ejector (40) is provided with: a nozzle (41) for ejecting a first fluid; a suction chamber (42) for sucking in a second fluid by means of a reduction in pressure caused by the ejection of the first fluid from the nozzle (41); a diffuser (43) which, while increasing the pressure of the first fluid, which has been ejected from the nozzle (41), and the pressure of the second fluid, which has been sucked-in into the suction chamber (42), discharges the first and second fluids; and an orifice plate (44) provided downstream of the diffuser (43).

Description

Ejector and vacuum generator equipped with the same

The technique disclosed herein relates to an ejector and a vacuum generation apparatus including the ejector.

Conventionally, an ejector and a vacuum generator equipped with the ejector are known. For example, the vacuum generator disclosed in Patent Document 1 circulates a fluid stored in a tank as a first fluid through a pump and an ejector, thereby generating a suction force in the ejector and sucking a second fluid. ing.

JP 2014-156814 A

In such an ejector, the nozzle and the diffuser are designed so that the second fluid can be sucked as desired.

However, even an ejector having a nozzle and a diffuser designed as such is difficult to suck the second fluid as desired unless it functions properly as an ejector. For example, the fluid passing through the diffuser may not be sufficiently boosted, in which case the ejector will not function properly.

The technology disclosed herein has been made in view of such points, and the purpose thereof is to make the ejector function properly.

The ejector disclosed herein includes a nozzle that ejects the first fluid, a suction chamber that sucks the second fluid due to a pressure drop caused by the ejection of the first fluid from the nozzle, and the first ejected from the nozzle. A diffuser that discharges the first fluid and the second fluid sucked into the suction chamber while increasing the pressure, and a fluid resistance portion provided downstream of the diffuser.

Further, the vacuum generator disclosed herein is connected to the ejector, the tank for storing the first fluid and the second fluid that have passed through the diffuser, and the tank, and the fluid in the tank is A pump that pumps the fluid as one fluid to the ejector, and recirculates the fluid in the tank through the pump and the ejector, thereby sucking the second fluid through the ejector.

According to the ejector, by providing the fluid resistance portion downstream of the diffuser, the fluid passing through the diffuser can be sufficiently boosted. As a result, the ejector can function properly.

According to the vacuum generating device, the fluid passing through the diffuser can be sufficiently boosted by providing the fluid resistance portion downstream of the diffuser. As a result, the ejector can function properly, and as a result, the second fluid can be sucked appropriately.

FIG. 1 is a piping system diagram illustrating a schematic configuration of a vacuum steam heating system according to an embodiment. FIG. 2 is a schematic configuration diagram of the vacuum generator. FIG. 3 is a graph showing the relationship between the vacuum failure phenomenon, the opening ratio of the orifice plate, and the circulating water temperature. FIG. 4 is a graph showing the relationship between the degree of vacuum and the amount of suction in the ejector.

Hereinafter, exemplary embodiments will be described with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

FIG. 1 is a piping system diagram showing a schematic configuration of a vacuum steam heating system 1 according to an embodiment.

A vacuum steam heating system (hereinafter referred to as “heating system”) 1 includes a reaction kettle 20 that heats an object with steam, a steam supply rod 11 that feeds steam from a steam generation unit (not shown) to the reaction kettle 20, A discharge pipe 13 for discharging the drain generated in the reaction kettle 20 and a vacuum generator 30 for sucking the drain through the discharge pipe 13 are provided. The heating system 1 includes a fluid circuit 10, and the fluid circuit 10 includes a steam supply tank 11, a reaction kettle 20, a discharge pipe 13, and a vacuum generator 30. The heating system 1 heats the object accommodated in the reaction kettle 20 with saturated steam below atmospheric pressure.

The reaction kettle 20 includes a kettle main body 21 in which an object is accommodated and a jacket portion 22 formed over substantially the entire circumference of the kettle main body 21. A steam supply rod 11 is connected to the jacket portion 22. The steam supply rod 11 is provided with a supply valve 14 that is an on-off valve. The steam generated by the steam generation unit is supplied to the jacket unit 22 through the steam supply pipe 11. In the reaction kettle 20, the steam supplied to the jacket portion 22 indirectly heat exchanges with the object inside the kettle body 21 to condense (liquefy), and the object is heated. That is, the target object is heated by being given the latent heat of condensation of steam.

The discharge pipe 13 has one end (inflow end) connected to the lower end of the jacket portion 22 and the other end (outflow end) connected to the vacuum generator 30. The discharge pipe 13 discharges drain (condensate) generated by condensing steam in the jacket portion 22. The discharge pipe 13 is provided with a steam trap 15 that automatically discharges only the drained water.

The vacuum generator 30 includes a drain tank 31 that stores drain, a pump 32 that pumps the drain in the drain tank 31, and an ejector 40 that sucks drain from the reaction kettle 20 through the discharge pipe 13. . The drain tank 31, the pump 32, and the ejector 40 are connected by a pipe 34, and a circulation channel including the drain tank 31, the pump 32, and the ejector 40 is formed. The vacuum generator 30 circulates the drain stored in the drain tank 31 via the pump 32 and the ejector 40, thereby generating a suction force in the ejector 40 and sucking the drain from the reaction kettle 20.

FIG. 2 shows a schematic configuration diagram of the vacuum generator 30. The pipe 34 includes a first pipe 34 a that connects the drain tank 31 and the pump 32, a second pipe 34 b that connects the pump 32 and the ejector 40, and a third pipe 34 c that connects the ejector 40 and the drain tank 31. have. The drain tank 31 is an example of a tank. The pump 32 is driven by a motor 35.

The ejector 40 includes a nozzle 41 that ejects the first fluid, a suction chamber 42 that sucks the second fluid by the negative pressure generated by the ejection of the first fluid from the nozzle 41, and the first fluid ejected from the nozzle 41 and the suction A diffuser 43 that discharges the second fluid sucked into the chamber 42 while increasing the pressure, and two orifice plates 44 provided downstream of the diffuser 43 are provided.

The nozzle 41 is connected to the downstream end of the second pipe 34b. At least the ejection port 41 a of the nozzle 41 is accommodated in the suction chamber 42.

The suction chamber 42 also accommodates at least the upstream end of the diffuser 43. The suction chamber 42 is connected to the outflow end of the discharge pipe 13. In the suction chamber 42, the second fluid is sucked from the discharge pipe 13 by the negative pressure (pressure drop) generated when the first fluid is ejected from the nozzle 41. That is, in the suction chamber 42, a suction force for sucking the second fluid is generated by the negative pressure generated by the jet pump effect of the first fluid.

The diffuser 43 has a linear flow path. The flow passage cross-sectional area of the diffuser 43 increases from the upstream toward the downstream. Therefore, the fluid passing through the diffuser 43 decelerates and pressurizes as it flows through the diffuser 43 from upstream to downstream. A third pipe 34 c is connected to the downstream end of the diffuser 43.

The orifice plate 44 is a disk-shaped member having a circular opening 44a at the center. The orifice plate 44 is an example of a fluid resistance portion. The orifice plate 44 is disposed in the third pipe 34c. Specifically, the upstream orifice plate 44 is disposed at the upstream end of the third pipe 34c, that is, at the connection portion between the diffuser 43 and the third pipe 34c. The downstream orifice plate 44 is disposed at the downstream end of the third pipe 34 c, that is, at the connection portion between the third pipe 34 c and the drain tank 31. The diffuser 43 and the third pipe 34c are connected to each other via a flange portion, and the upstream orifice plate 44 is sandwiched between the flange portion of the diffuser 43 and the flange portion of the third pipe 34c. The third pipe 34 c and the drain tank 31 are connected to each other via a flange portion, and the downstream orifice plate 44 is sandwiched between the flange portion of the third pipe 34 c and the flange portion of the drain tank 31.

The area of the opening 44a of the upstream orifice plate 44 is smaller than the flow path cross-sectional area of the downstream portion of the orifice plate 44 in the third pipe 34c. Similarly, the area of the opening 44a of the downstream orifice plate 44 is smaller than the flow path cross-sectional area of the upstream portion of the orifice plate 44 in the third pipe 34c. That is, the upstream and downstream orifice plates 44 have a function of reducing the flow passage cross-sectional area of the flow passage on the downstream side of the diffuser 43.

The area of the opening 44 a of the upstream orifice plate 44 is the same as the area of the opening 44 a of the downstream orifice plate 44. In the present embodiment, the flow passage cross-sectional area of the third pipe 34c is uniform from upstream to downstream, so the ratio of the area of the opening 44a to the flow passage cross-sectional area of the third pipe 34c in the upstream orifice plate 44 (opening The area of 44a / the cross-sectional area of the third pipe 34c, hereinafter referred to as "opening ratio") is equal to the opening ratio of the downstream orifice plate 44.

In the vacuum generator 30 configured as above, the drain in the drain tank 31 is pressurized by the pump 32 and supplied to the nozzle 41 of the ejector 40 as the first fluid. By discharging the drain from the nozzle 41 to the suction chamber 42, a negative pressure is generated around the nozzle 41, and the drain of the reaction vessel 20 is sucked into the suction chamber 42 as the second fluid through the discharge pipe 13. The drain sprayed from the nozzle 41 and the drain sucked from the discharge pipe 13 are mixed in the suction chamber 42 and discharged through the diffuser 43. At this time, the drain decelerates and pressurizes as it flows through the diffuser 43 to the downstream side. Finally, the drain flows into the drain tank 41. Thus, the drain in the reaction kettle 20 is collected in the drain tank 31.

Here, by providing the orifice plate 44 on the downstream side of the diffuser 43, the ejector 40 can be appropriately functioned, and the drain can be appropriately sucked from the reaction kettle 20.

Specifically, by providing the orifice plate 44 on the downstream side of the diffuser 43, the fluid resistance in the flow path on the downstream side of the diffuser 43 can be increased, and the pressure in the flow path on the downstream side of the diffuser 43 can be increased. . Thereby, the pressure of the fluid passing through the diffuser 43 can be sufficiently increased. If the pressure on the downstream side of the diffuser 43 is small, the fluid passing through the diffuser 43 is not sufficiently boosted. In the ejector 40, the nozzle 41 and the diffuser 43 are designed on the premise of a pressure difference between the inlet of the nozzle 41 and the outlet of the diffuser 43. Therefore, if the pressure difference becomes too small, the negative pressure in the suction chamber 42 is appropriately set. Can not be generated. On the other hand, by providing the orifice plate 44 on the downstream side of the diffuser 43, the fluid passing through the diffuser 43 can be sufficiently boosted, so that the negative pressure in the suction chamber 42 can be appropriately generated. That is, the ejector 40 can function appropriately.

Further, whether or not the fluid can be sufficiently increased by the diffuser 43 is determined not only by the pressure on the downstream side of the diffuser 43 but also the water temperature of the drain circulating in the vacuum generator 30 (hereinafter referred to as “circulation water temperature”). Also depends on. As the circulating water temperature increases, the viscosity of the drain decreases, so that the pressure increase (pressure recovery) when the drain passes through the diffuser 43 is reduced. That is, the higher the circulating water temperature, the more appropriately the negative pressure in the suction chamber 42 cannot be generated.

FIG. 3 shows the relationship between a phenomenon in which a negative pressure cannot be appropriately generated in the suction chamber 42 (hereinafter referred to as “vacuum non-occurrence phenomenon”), the opening ratio of the orifice plate 44 and the circulating water temperature. A solid line in FIG. 3 indicates a boundary line where a vacuum failure phenomenon occurs when only one orifice plate 44 is provided. A vacuum non-occurrence phenomenon occurs in a region above the boundary line (that is, the side where the circulating water temperature is high) (the hatched region in the figure in the case of the solid line). A broken line in FIG. 3 indicates a boundary line where a vacuum failure phenomenon occurs when two orifice plates 44 are provided.

When the orifice plate 44 is not provided (corresponding to an opening ratio of 100%), the circulating water temperature (hereinafter referred to as “boundary water temperature”) that becomes a boundary where the vacuum non-occurrence phenomenon does not occur is T1. As can be seen from FIG. 3, the boundary water temperature can be increased as the opening 44a of the orifice plate 44 is reduced. That is, it is possible to increase the circulating water temperature that does not cause a vacuum failure phenomenon. Furthermore, the boundary water temperature can be further increased by changing the number of orifice plates 44 from one to two (see the broken line). This is because as the orifice plate 44 increases, the pressure in the flow path on the downstream side of the diffuser 43 increases.

However, if the opening ratio of the orifice plate 44 is reduced to increase the fluid resistance too much, the flow rate of the drain flowing through the third pipe 34c, that is, the flow rate of the drain passing through the diffuser 43 is reduced. As a result, the flow rate of drain sucked from the reaction kettle 20 through the discharge pipe 13 is also reduced.

On the other hand, by providing a plurality of orifice plates 44, the fluid resistance can be increased while securing the flow rate. FIG. 4 is a graph showing the relationship between the degree of vacuum and the amount of suction in the ejector. In FIG. 4, the solid line indicates a case where only one orifice plate 44 having an aperture ratio of 60% is provided, and the broken line indicates a case where two orifice plates 44 having an aperture ratio of 75% are provided. When the degree of vacuum is high (for example, when the degree of vacuum is 100 kPaG), that is, when the ejector 40 is functioning properly, the configuration in which two orifice plates 44 having an opening ratio of 75% are provided is an orifice having an opening ratio of 60%. The amount of suction is larger than the configuration in which only one plate 44 is provided. The configuration in which only one orifice plate 44 with an opening ratio of 60% is provided can sufficiently increase the boundary water temperature (see FIG. 3), but the opening ratio is too small and the suction amount is reduced. On the other hand, the configuration in which two orifice plates 44 having an aperture ratio of 75% are provided can not only sufficiently increase the boundary water temperature (see FIG. 3), but also ensure a suction amount. That is, by increasing the number of orifice plates 44, the boundary water temperature can be increased while increasing the aperture ratio and securing the suction amount.

As described above, the ejector 40 is ejected from the nozzle 41 that ejects the first fluid, the suction chamber 42 that sucks the second fluid due to the pressure drop caused by the ejection of the first fluid from the nozzle 41, and the nozzle 41. A diffuser 43 that discharges the first fluid and the second fluid sucked into the suction chamber 42 while increasing the pressure, and an orifice plate 44 provided downstream of the diffuser 43 are provided.

According to this configuration, by providing the orifice plate 44 downstream of the diffuser 43, the pressure in the flow path on the downstream side of the diffuser 43 can be increased. Thereby, the fluid passing through the diffuser 43 can be sufficiently boosted, and as a result, the ejector 40 can function properly.

For example, in order to reduce the size of the ejector 40 and the vacuum generator 30, the pipe 34 (particularly, the third pipe 34c) may be short. In such a case, the pressure on the downstream side of the diffuser 43 tends to be small, and the pressure of the fluid passing through the diffuser 43 may be insufficient. Even in such a configuration, the fluid passing through the diffuser 43 can be sufficiently pressurized by providing the orifice plate 44. That is, the configuration in which the orifice plate 44 is provided is particularly effective for the small ejector 40 and the vacuum generator 30.

In addition, since the orifice plate 44 restricts the cross-sectional area of the flow path from the outside, it is possible to give an appropriate pressure loss to the fluid without excessively impeding the flow of the fluid flowing while spreading outward.

Also, since a plurality of orifice plates 44 are provided, the pressure in the flow path downstream of the diffuser 43 can be increased without making the flow rate of the fluid passing through the diffuser 43 too small.

Furthermore, the area of the opening 44a of the orifice plate 44 is smaller than the cross-sectional area of the flow path before and after the resistance portion of the orifice plate 44.

That is, the orifice plate 44 increases the fluid resistance by restricting the flow path.

The vacuum generator 30 is connected to the ejector 40, the drain tank 31 that stores the first fluid and the second fluid that have passed through the diffuser 43, and the drain tank 31, and the fluid in the drain tank 31 is used as the first fluid. And a pump 32 that pumps the ejector 40. The fluid in the drain tank 31 is recirculated through the pump 32 and the ejector 40 to suck the second fluid through the ejector 40.

According to this configuration, since the ejector 40 can function properly as described above, the second fluid can be appropriately sucked through the ejector 40.

The ejector 40 and the vacuum generator 30 can be applied not only to the vacuum steam heating system 1 but also to other systems. For example, the ejector 40 and the vacuum generator 30 may be applied to a system that performs not only steam heating but also cooling. Further, the steam used in the system is not limited to steam below atmospheric pressure.

Furthermore, although the ejector 40 circulates water, it is not limited to a liquid ejector. That is, the ejector 40 may circulate gas.

In the above embodiment, the orifice plate is adopted as the fluid resistance portion. However, the fluid resistance portion may adopt any configuration as long as the fluid resistance is increased more than the front and rear portions. For example, the fluid resistance portion may be a throttle portion that gradually narrows the cross-sectional area of the flow path, a valve that can reduce the cross-sectional area of the flow path, a bellows tube, or the like.

Furthermore, in the above-described embodiment, two orifice plates 44 are provided as fluid resistance parts, but the number of fluid resistance parts may be one or three or more.

The technique disclosed herein is useful for an ejector and a vacuum generator provided with the ejector.

1 Vacuum Steam Heating System 30 Vacuum Generator 31 Drain Tank (Tank)
32 Pump 40 Ejector 41 Nozzle 42 Suction chamber 43 Diffuser 44 Orifice (fluid resistance part)

Claims

A nozzle for ejecting the first fluid;
A suction chamber for sucking the second fluid by a pressure drop caused by the ejection of the first fluid from the nozzle;
A diffuser for discharging the first fluid ejected from the nozzle and the second fluid sucked into the suction chamber while increasing the pressure;
An ejector comprising: a fluid resistance portion provided downstream of the diffuser.
The ejector according to claim 1,
An ejector comprising a plurality of the fluid resistance portions.
The ejector according to claim 1 or 2,
The ejector according to claim 1, wherein a flow path cross-sectional area of the fluid resistance portion is smaller than a flow path cross-sectional area before and after the fluid resistance portion.
The ejector according to any one of claims 1 to 3,
The ejector according to claim 1, wherein the fluid resistance portion is formed of an orifice plate.
The ejector according to any one of claims 1 to 4,
A tank for storing the first fluid and the second fluid that have passed through the diffuser;
A pump connected to the tank and pumping the fluid in the tank as the first fluid to the ejector;
A vacuum generator for sucking the second fluid through the ejector by recirculating the fluid in the tank through the pump and the ejector.