NL2019950B1 - Adjustable nozzle - mixer distance for ejector - Google Patents

Abstract

An ejector is provided comprising a motive nozzle module, arranged to provide a first mass flow, and comprising a first motive nozzle, a suction chamber and a mixing chamber, provided downstream of the motive nozzle module and the suction chamber, arranged for mixing mass from the first mass flow and the second mass flow into a third mass flow. In this ejector, the mixing chamber and the first motive nozzle are arranged to translate relative to each other over an axis of the ejector for adjusting a distance between the first motive nozzle and the mixing chamber. This ejector allows controlling of a distance between the first motive nozzle and the mixing chamber. As a result, the location in the mixing chamber at which the shock wave occurs may be controlled.

Description

TECHNICAL FIELD

The various aspects and embodiments relate to an ejector for increasing pressure in a refrigerant, provided in a compressive cooling system.

BACKGROUND

Conventional vapour-compression refrigeration systems comprise a closed loop system for a refrigerant, with a compressor, a condenser, an expansion valve and an evaporator. If used with chlorofluorocarbons, such systems are able to operate at sufficient efficiency. However, these refrigerants are prohibited in a lot of countries, or their use is heavily discouraged. For efficient use of more environmentally friendly refrigerants, e.g. CO2, additional measures are required for operating at a feasible efficiency level. To increase efficiency of such systems, ejectors are used for increasing pressure in a vapour-compression refrigeration system.

An ejector is a passive component comprising a nozzle for providing a first mass stream of refrigerant at a high speed. The high speed refrigerant flow is provided to a suction chamber, in which a second mass flow is available. Due to the high speed, the first mass stream takes along the second mass stream towards a mixing chamber. Gradually, the speed of the mass flows mixing into a third mass flow decreases until below the speed of sound, at which point a shock wave occurs and pressure increases significantly.

Ejectors are suitable for pressure increase in refrigerant flows having a substantially constant mass flow. At lower or higher mass flows, efficiency of an ejector decreases. With requirements for refrigerant supply varying due to variations in demand for cooling, there is a demand for adjustable ejectors. NL1041046 discloses an adjustable ejector. A flow-through area of a nozzle may be adjusted by inserting a needle in the nozzle. The needle has to be provided in the exact middle of the nozzle to prevent unwanted turbulence and other flow disturbances that affect the efficiency of the ejector. Despite precise machining, this is difficult to establish.

SUMMARY

It is preferred to provide an ejector that may be adjusted to work efficiently at different mass flow rates of refrigerant. A first aspect provides an ejector, comprising a motive nozzle module, arranged to provide a first mass flow, and comprising a first motive nozzle, provided at a downstream side of the motive nozzle module, a suction chamber, arranged to provide a second mass flow; and a mixing chamber, provided downstream of the motive nozzle module and the suction chamber, arranged for mixing mass from the first mass flow and the second mass flow into a third mass flow. In this ejector, the mixing chamber and the first motive nozzle are arranged to translate relative to each other over an axis of the ejector for adjusting a distance between the first motive nozzle and the mixing chamber.

This ejector allows controlling of an effective flow-through area of the mixing chamber. As a result, the location at which the shock wave occurs may be controlled. With a fixed flow-through area, the location of the shock wave depends on the magnitude of the mass flows. The ejector according to this aspect allows to counterbalance this effect by controlling the distance between the first motive nozzle and the mixing chamber.

In an embodiment, the motive nozzle module comprises a flange extending outwardly from the motive nozzle module, and the ejector comprises a housing, which further comprises a flange chamber. The flange chamber comprises a downstream fluid chamber, an upstream fluid chamber, a downstream wall; and an upstream wall. The housing is arranged to constrain the axial translation of the motive nozzle module flange in-between the upstream wall and the downstream wall.

The volumes of the fluid chambers may be controlled by withdrawing fluid or injecting fluid - gas or liquid. This may be done in various ways and controlled in various ways to control the position of the first motive nozzle relative to the mixing chamber. As an advantage, no local actuator is required, which allows for compact design. In embodiments, a self-controiled system may be used by connecting the fluid chambers to the main fluid channel through the ejector, either upstream or downstream of the first motive nozzle. A second aspect provides a refrigeration system, comprising an evaporator, a compressor, a condenser an expansion valve, preferably, a liquid separator and an ejector according to the first aspect or any embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects and embodiments thereof will now be elucidated in further detail in conjunction with drawings. In the drawings:

Fig. 1 shows an ejector;

Fig. 2A shows a detailed view of a motive nozzle module;

Fig. 2B shows another detailed view of the motive nozzle module;

Fig. 2C shows another detailed view of the motive nozzle module;

Fig. 3A shows the first motive nozzle module in an ejector housing;

Fig. 3B shows the ejector provided with an external fluid source;

Fig. 3C shows the first motive nozzle module and the flange chamber in fluid connection with a first mass flow;

Fig. 3D shows the ejector provided with an external fluid source;

Fig. 3E shows the first motive nozzle module and the flange chamber in fluid connection with a first mass flow;

Fig. 3F shows the first motive nozzle module provided with an actuator;

Fig. 3G shows the first motive nozzle module with different fluid conducts;

Fig. 4A shows a control body in a downstream position in the mixing chamber;

Fig. 4B shows the control body in an upstream position in the mixing chamber;

Fig. 5A shows a vapour-compression refrigeration system comprising the ejector; and

Fig. 5B shows the vapour-compression refrigeration system comprising the ejector comprising a refrigeration system control module

DETAILED DESCRIPTION

Figure 1, shows an embodiment of an ejector 100, comprising an ejector housing 102, a first motive nozzle module 200, a suction chamber 110, a mixing chamber 300, and a control module 310.

The first motive nozzle module 200 further comprises, in the embodiment shown in Fig. 1, a second motive nozzle module 220 and a third motive nozzle module 230. The third motive nozzle module 230 is nested in the second motive nozzle module 220, and the second motive nozzle module 220 is nested in the first motive nozzle module 200. The first motive nozzle module 200, the second motive nozzle module 220, and the third motive nozzle module 230 all comprise one or more through holes 225. The through holes 225 may be provided in a cylindrical part of the motive nozzle modules, or, alternatively or additionally, in a conical part converging downstream of the motive nozzle modules. Additionally, the first motive nozzle module 200, the second motive nozzle module 220, and the third motive nozzle module 230 are arranged to translate over an ejector axis 101.

The first motive nozzle module 200 is in an embodiment provided with a flange 210, which protrudes outward from an external surface of the first motive nozzle module 200. The ejector housing 102 is provided with a flange chamber 212, arranged to retain the flange 210. The flange chamber 212 is provided with an upstream chamber 216 and a downstream chamber 214. The ejector housing 102 comprises an upstream wall 217 and a downstream wall 215. The upstream wall 217 and the downstream wall 215 are arranged to constrain the translating movement of the first motive nozzle module 200 over the ejector axis 101 between an upstream position, as shown in Fig. 3B, and a downstream position, as shown in Fig. 3D.

In the embodiment shown in Fig. 1, at least one of the second motive nozzle module 220 and the third motive nozzle module 230 are arranged to be mechanically connected to a motive nozzle module insert actuator 202, as shown in Fig. 2A. The motive nozzle module insert actuator 202 is in turn attached to the ejector housing 102 as shown in Fig. 1.

In an embodiment of the ejector 100 which comprises additional motive nozzle modules, additional to the second motive nozzle module 220 and the third motive nozzle module 230, the additional motive nozzle modules are also arranged to translate relative to a first motive nozzle 211. In the embodiment of the ejector 100 which comprises additional motive nozzle modules, all subsequent motive nozzle modules are arranged to be nested in one another.

The control module 310 is arranged to at least partially be provided in the mixing chamber 300. The control module 310 comprises a holding unit 318, a control module actuator 320, a control shaft 316, and a control body 312. The control body 312 is arranged to be translated over an axis 315 of the mixing chamber, and comprises a tip 314 and a tapered section 313. The mixing chamber 300 comprises a mixing conduit 302, and an inner wall 303.

The ejector 100 is arranged to be provided with a first mass flow at an upstream side. The suction chamber 110 is arranged to be provided with a second mass flow, and the mixing chamber 300 is arranged to mix the first mass flow and the second mass flow into a third mass flow. In all the figures, mass flows from left to right. By virtue of the high pressure of the first mass flow, the low pressure second mass flow from the suction chamber 110 is sucked into the mixing chamber 300. The third mass flow, which combines the first mass flow and the second mass flow, than has a pressure higher than the low pressure of the second mass flow.

The ejector 100 is arranged to be operated in a refrigeration system under varying working loads, depending e.g. on an ambient temperature and on various heat loads acting on the refrigeration system. In order to have the refrigeration system operating as efficient as possible, the ejector 100 is arranged to have three parameters controlled.

First, the size of a minimal flow-through area for the first mass flow can be controlled by inserting one or more motive nozzle modules in the first motive nozzle module 200 as each motive nozzle module has a different sized flow-through opening. Next, the distance between the first motive nozzle 211 and the mixing chamber 300 can be controlled by translating at least one of the first motive nozzle module 200 and the mixing chamber 300 over the ejector axis 101. Finally, the flow-through area for the third mass flow can be altered by translating the control body 312 over the mixing chamber axis 315. With the ability to control the flow-through area for the third mass flow, the pressure in the mixing chamber 300 and the speed of the third mass flow can be controlled. A too high pressure in the mixing chamber 300 combined with a too low speed of the third mass flow can cause the direction of the third mass flow to reverse, causing the third mass flow to flow back into the suction chamber 110. This effect can be prevented by translating the control body 312 over the mixing chamber axis 315 to another position wherein the flow-through area for the third mass flow is larger.

In the embodiment of the ejector 100 as shown in Fig. 1, the mixing chamber 300 is provided with the control module 310, comprising the control body 312. The control body 312 is attached to the control shaft 316, which in turn is attached to the holding unit 318. The holding unit 318 is arranged to attach the control module 310 to the ejector housing 102, such that the control module actuator 320 may translate the control body 312 relative to the ejector housing 102 over an axis 315 of the mixing chamber. The position of the control body 312 in the mixing chamber 300 determines, when the third mass flow has a speed higher than Mach 1, where in the mixing chamber 300 a standing shock wave occurs due to a decrease in flow speed over the control body 312 below Mach 1, the speed of sound. If the speed of the third mass flow is above Mach 1, a narrowing of the flow path of the third mass flow due to the control body 312 results in a decrease of the speed of the third mass flow. At the point in the mixing chamber where the speed of the third mass flow drops below Mach 1, a standing shockwave or a sonic boom occurs, resulting in an increase in pressure at the location of the standing shockwave. The pressure in the part of the third mass flow with a speed below Mach 1 increases as the flow-through area of the flow path of the third mass flow increases.

Fig. 2A shows a detailed view of the first motive nozzle module 200 as part of the ejector of Fig. 1. The first motive nozzle module 200 comprises the first motive nozzle 211, which comprises a first minimal flow-through area 261. Additionally inserted in the first motive nozzle module 200 are the second motive nozzle module 220 and the third motive nozzle module 230. The second motive nozzle module 220 comprises a second motive nozzle 221, which comprises a second minimal flow-through area 262. The third motive nozzle module 230 comprises a third motive nozzle 231, which comprises a third minimal flow-through area 263. Preferably, the third minimal flow-through area 263 comprised by the third motive nozzle 231 is a smaller flow-through area than the second minimal flowthrough area 262 comprised by the second motive nozzle 221, which in turn is a smaller flow-through area than the first minimal flow-through area 261 comprised by the first motive nozzle 211.

The motive nozzle modules may be provided with an additional tapered section at the downstream side of the minimal flow-through area of the motive nozzle module, downstream of the first mass flow. Respectively, a first additional section 241 for the first motive nozzle module 200, a second additional section 242 for the second motive nozzle module 220, and a third additional section 243 for the third motive nozzle module 230 are provided. All three additional sections are tapered such that the flow-through area increases towards the side downstream of the first mass flow.

Between an inner wall 206 of the first motive nozzle module and an outer wall 226 of the second motive nozzle module, a first urging element 223 may be provided, arranged to urge the second motive nozzle module 220 upstream of the first motive nozzle module 200. In an alternative embodiment, the first urging element 223 is provided upstream of the second motive nozzle module 220. A second urging element 233 may be provided between an inner wall of the second motive nozzle module 220 and an outer wall of the third motive nozzle module 230. The second urging element 233 is arranged to urge the third motive nozzle module 230 upstream of the second motive nozzle module 220. In an additional embodiment, the second urging element 233 may also be provided upstream of the third motive nozzle module 230. The first urging element 223 and the second urging element 233 may comprise a helical spring, wave spring, compression spring, extension spring, Belleville spring, any other urging element, or any combination thereof.

In an embodiment, a stiffness, e.g. measured in N/mrn, of the first urging element 223 is lower than a stiffness of the second urging element 233. The stiffness of the first urging element 223 is preferably two times less stiff than the second urging element 233, more preferably five times less stiff, even more preferably ten or more times less stiff. This allows a single motive nozzle module insert actuator 202 to operate the translation of both the second motive nozzle module 220 and the third motive nozzle module 230.

Upon actuation, the first urging element 223 is significantly more compressed than the second urging element 233, causing the second motive nozzle module 220 to abut the first motive nozzle module 200 first. When the second motive nozzle module 220 abuts the first motive nozzle module 210, the minimal flow-through area for the first mass flows is decreased from the first minimal flow-through area 261 to the second minimal flow-through area 262. After the second motive nozzle module 220 has abutted the first motive nozzle module 200, the second urging element 233 is compressed and the third motive nozzle module 230 abuts the second motive nozzle module 220, as shown respectively in Fig. 2A, 2B, and 2C.

When the third motive nozzle module 230 abuts the second motive nozzle module 220, the minimal flow-through area for the first mass flow is decreased from the second minimal flow-through area 262 to the third minimal flow-through area 263. Thus, the addition of additional motive nozzle modules to the first motive nozzle module 200 allows a stepwise control of the minimal flow-through area for the first mass flow. On the one hand, a decrease in minimal flow-through area for the first mass flow decreases the speed of the first mass flow and hence increases the pressure of the first mass flow at the minimal flow-through area. On the other hand, an increase of the minimal flow-through area for the first mass flow increases the speed of the first mass flow and hence decreases the pressure of the first mass flow at the minimal flow-through area of the first mass flow.

In another embodiment of the ejector 100, the first urging element 223 is arranged to urge the second motive nozzle module 220 downstream towards the first motive nozzle module 200, and the second urging element 233 is arranged to urge the third motive nozzle module 230 downstream towards the second motive nozzle 221. The motive nozzle module insert actuator 202 is in this embodiment arranged to provide an upstream force to at least one of the second motive nozzle module 220 and the third motive nozzle module 230.

Likewise, in another alternative that may be combined with the latter, the second motive nozzle module 220 may be left at the most downstream position in the first motive nozzle module 200, while the third motive nozzle module 230 is moved upstream, by means of an urging element, an actuator, other, or a combination thereof. As an option, the third motive nozzle module 230 may remain nested in the second motive nozzle module 220 during this movement and, optionally, be moved out of the second motive nozzle module 220 at a later moment, by means of an urging element, an actuator, other, or a combination thereof.

In a further embodiment, the second motive nozzle module 220 comprises one or more through holes 225. Additionally, the third motive nozzle 231 comprises one or more through holes 225. These through holes 225 are arranged to provide an additional flow path for the first mass flow to the first motive nozzle 211, in addition to the flow path through the second motive nozzle 221 and the third motive nozzle 231. With this configuration, it is possible to provide the first mass flow with different minimal flow-through areas, depending on the position of the second motive nozzle module 220 and the third motive nozzle module 230 in the first motive nozzle module 200.

The through holes 225 comprised by the second motive nozzle module 220 are provided in at least one of a straight section of the second motive nozzle module 220, and a tapered section of the second motive nozzle module 220, as shown in Fig. 2A. Similarly for the third motive nozzle module 230, the through holes 225 comprised by the third motive nozzle module 230 are provided at least in one of a straight section and a tapered section of the third motive nozzle module 230. Preferably, the through holes 225 are provided axisymmetric around the axis 101 of the ejector.

The motive nozzle module insert actuator 202, arranged to provide translation for at least one of the second motive nozzle module 220 and the third motive nozzle module 230 may be of a pneumatic, hydraulic, mechanical, electromechanical type, any other type, or any combination thereof. The motive nozzle module insert actuator 202 is connected to the third motive nozzle module 230. In an additional embodiment, the motive nozzle module insert actuator 202 may be connected to at least one of the second motive nozzle module 220 and the third motive nozzle 231.

Furthermore, the second motive nozzle module 220 comprises a second motive nozzle module inner wall 227 and a second motive nozzle module outer wall 226. The third motive nozzle module 230 comprises a third motive nozzle module outer wall 236. Fig. 2B shows the second motive nozzle module 220 in a downstream position, wherein the second motive nozzle module 220 is arranged to substantially seal off the flow path between the outer wall 226 of the second motive nozzle module and the inner wall 206 of the first motive nozzle module 200. In a preferred embodiment, the shape of at least part of the second motive nozzle module 220 corresponds to a shape of the inner wall 206 of the first motive nozzle module 206.

In another embodiment, the outer wall 226 of the second motive nozzle module may be provided with a thread corresponding to a thread provided in the inner wall 206 of the first motive nozzle module. By providing a motive nozzle module insert actuator 202 that is arranged to rotate the second motive nozzle module 220, the second motive nozzle module 220 is arranged to translate over the ejector axis 101 inside the first motive nozzle module 200. A similar arrangement can be envisioned for subsequent additional motive nozzle modules provided inside the second motive nozzle module 220.

Fig. 2C shows the third motive nozzle module 230 in a downstream position, wherein the third motive nozzle module 230 is arranged to substantially seal off a flow path between the outer wall 236 of the third motive nozzle module 230 and the inner wall 227 of the second motive nozzle module 220. In a preferred embodiment, at least part of an outer shape of the third motive nozzle module 230 corresponds to a shape of the inner wall 227 of the second motive nozzle module 220.

Fig. 3A shows a detailed view of the first motive nozzle module 200 as part of the ejector 100 as shown in Fig. 1. The first motive nozzle module 200 comprises the flange 210, arranged to extend outwardly from the exterior of the first motive nozzle module 200. Additionally, the ejector housing 102 comprises the flange chamber 212, arranged to receive the flange 210 between an upstream position and a downstream position. The flange chamber 212 comprises the downstream chamber 214 and the upstream chamber 216. The flange 210, in a downstream position, abuts the downstream wall 215 comprised by the ejector housing 102. In an upstream position, the flange 210 abuts the upstream wall 217 comprised by the ejector housing 102.

In an additional embodiment, as shown in Fig. 3B, the downstream chamber 214 is provided with a downstream fluid inlet 244 and a downstream fluid outlet 245. In another embodiment of the ejector housing 102, the downstream fluid inlet 244 and the downstream fluid outlet 245 are combined in the same conduit. Additionally, the ejector 100 is provided with an external fluid source 213, in fluid connection with the downstream fluid inlet 244. The external fluid source 213 may additionally comprise a pumping device for providing pressurized fluid to the downstream fluid inlet 244. Upon pressurisation of the downstream chamber 214, the pressure in the downstream chamber 214 becomes higher than the pressure in the upstream chamber 216. This, in turn, causes the first motive nozzle module 200 to translate upstream. A pressurisation of the upstream chamber 216, in e.g. an embodiment of the ejector as shown in Fig. 3C and Fig. 3E, to a higher pressure than the pressure in the downstream chamber 214 causes the first motive nozzle module 200 to translate downstream. A difference between a force applied to a downstream side of the flange 210 and an upstream side of the flange 210 will cause the first motive nozzle module to translate 200. As the force applied to a surface depends on the area of the surface and the pressure at that surface, one can design a first motive nozzle module 200 with a different surface area at the downstream side of the flange 210 than the surface area at the upstream side of the flange. In such a configuration, different pressures may be applied at the upstream side of the flange 210 and the downstream side of the flange 210 for translating the first motive nozzle module 200.

Fig. 3C shows an additional embodiment of the ejector housing 102 and the first motive nozzle module 200, wherein the downstream chamber 214 is arranged to be in fluid connection with the first mass flow, provided upstream of the first motive nozzle 211. In this embodiment, the pressure of the first mass flow may be used to translate the first motive nozzle module 200 to the upstream position. The first mass flow can either be provided directly to the downstream chamber 214, or indirectly. An indirect connection between the first mass flow and the downstream chamber 214 may comprise a piston, bellow, pressure vessel, membrane, other connecting element, or any combination thereof.

Fig. 3E shows the first motive nozzle module 200 in the downstream position. In an additional embodiment, as shown in Fig. 3D, the ejector 100 further comprises the external fluid source 213, which is arranged to be in fluid connection with an upstream chamber fluid inlet 246. Also provided is an upstream fluid outlet 247. The external fluid source 213 may additionally comprise a pumping device for providing pressurized fluid to the downstream fluid inlet 244.

Fig. 3E shows an embodiment of the ejector 100 in which the upstream chamber fluid inlet 246 is arranged to be in fluid connection with the first mass flow, provided upstream of the first motive nozzle 211. The pressure of the first mass flow may in this embodiment be used to pressurise the upstream chamber 216 and in turn may be used to translate the first motive nozzle module 200 to the downstream position.

Fig. 3F shows yet another embodiment of the part of the ejector 100 comprising the first motive nozzle module 200. In this embodiment, the first motive nozzle module 200 is provided with a motive nozzle module actuator 254 at the upstream side, in which the motive nozzle module actuator 254 is arranged to translate the first motive nozzle module 200 over the ejector axis 101. The motive nozzle module actuator 254 may be of a pneumatic, hydraulic, mechanical, electromechanical type, other, or any combination thereof. Preferably, the motive nozzle module insert actuator 202 is fixed to the ejector housing 102.

Fig. 3G shows yet another embodiment of the first motive nozzle module 200 in the ejector housing 102. In this embodiment, to provide the translation of the first motive nozzle module 200 over the axis 101 of the ejector, a pressure difference between the downstream chamber 214 and the upstream chamber 216 is used to translate the first motive nozzle module 200 between the downstream wall 215 and the upstream wall 217. The downstream chamber 214 is provided with a downstream chamber conduit 284, arranged to act as an inlet and as an outlet for a pressurized fluid or gas. The upstream chamber 216 is provided with an upstream chamber conduit 286, arranged to act as an inlet and an outlet for a pressurized fluid or gas. The upstream chamber conduit 286 is provided in fluid connection with an upstream valve 288, wherein the upstream valve 288 is arranged to control a fluid flow between an upstream external fluid source 291, an upstream conduit 287, and the upstream chamber conduit 286. The downstream chamber conduit 284 is provided in fluid connection with a downstream valve 289, which is arranged to control a fluid flow between a downstream conduit 285, the downstream chamber conduit 284, and a downstream external fluid source 292. In this embodiment, the downstream external fluid source 292 and the upstream external fluid source 291 are arranged to provide a pressurised fluid. In an optional embodiment, the downstream external fluid source 292 is the same as the upstream external fluid source 291. To provide a low pressure to either the downstream chamber 214 or the upstream chamber 216, respectively the downstream conduit 285 or the upstream conduit 287 may be provided in fluid connection with the second mass flow, either directly or via e.g. a valve, pressure vessel, bellow, other connecting element, or any combination thereof. To provide a high pressure to either the downstream chamber 214 or the upstream chamber 216, respectively the downstream conduit 285 or the upstream conduit 287 may be provided in fluid connection with the first mass flow, either directly or via e.g. a valve, pressure vessel, bellow, other connecting element, or any combination thereof. A control system, not shown in Fig. 3F, may be provided to control the upstream valve 288 and the downstream valve 289, and herewith control the position of the first motive nozzle module 200 in the ejector housing 102.

In an alternative embodiment of the first motive nozzle module 200 in the ejector housing 102, the position of the first motive nozzle module 200 in the ejector housing 102 is automatically regulated by the pressure difference between the first mass flow and the second mass flow.

In yet another embodiment, the first motive nozzle module 200 is provided with a friction element, arranged to temporarily fixate the position of the first motive nozzle module 200 in the ejector housing 102.

The embodiments and any of the features provided in the embodiments of the first motive nozzle module 200 and the ejector housing 102 as shown in Fig. 3B, Fig. 3C, Fig. 3D, and Fig. 3E may be combined to form an additional embodiment of the first motive nozzle module 200, arranged to be translated in the ejector housing 102.

In yet another embodiment of the part of the ejector 100 comprising the first motive nozzle module 200, the first motive nozzle 211 is provided with one or more threads, which in combination with the motive nozzle module insert actuator 202 are arranged to provide translation of the first motive nozzle module 200 over the ejector axis 101.

In an additional embodiment, the first motive nozzle module 200 is provided with one or more racks and the ejector 100 is provided with one or more pinions, arranged to provide the translation of the first motive nozzle module 200 over the ejector axis 101. The one or more pinions may be provided with the motive nozzle module actuator 254, arranged to provide rotation of the one or more pinions.

In the embodiments described here above, the ejector housing 102 may be provided with one or more abutments, which may constrain the first motive nozzle module 200 between the downstream and the upstream position.

In yet another embodiment of the ejector 100, the mixing chamber 300 is arranged to translate over the ejector axis 101, wherein this translation is arranged to vary the distance between the operating motive nozzle and the mixing chamber 300, as shown in Fig. 1.

Fig. 4A shows a detailed view of the mixing chamber 300 of the ejector 100 as shown in Fig. 1, wherein the mixing chamber 300 comprises a mixing conduit 302 and the control module 310, arranged to control the flow-through area through which the third mass flow may flow.

In a preferred embodiment, the control module 310 comprises the control body 312 and the control shaft 316. In this embodiment, the control module 310 is provided downstream of the mixing conduit 302. In another embodiment, at least part of the control module 310 may be provided upstream of the mixing conduit 302, as shown in Fig. 4B.

Fig. 4A shows the control body 312 in a downstream position, wherein at least part of the control body 312 is provided downstream of the mixing conduit 302. When the control body 312 is at least partially inserted in the mixing conduit 302, a flow path is provided for the third mass flow between an outer wall 317 of the control body and an inner wall 303 of the mixing conduit. The control body 312 and the mixing conduit 302 both comprise a tapered section. Over the tapered section 313 of the control body, the control body 312 becomes wider in the downstream direction of the third mass flow. The tapered section of the mixing conduit 302 comprises at least one of a first tapered section in which the cross-sectional area perpendicular mass flow, and a second tapered section in which the cross-sectional area perpendicular to the axis 315 of the mixing chamber decreases downstream of the third mass flow. The combination of the tapered section of the mixing conduit 302 and the tapered section 313 of the control body, with the control body 312 provided inside the mixing conduit 302, allows the control of the flow-through area of the third mass flow between the outer wall 317 of the control body and the inner wall 303 of the mixing conduit by translating the control body 312 inside the mixing conduit 300. The flow-through area of the third mass flow is in this embodiment a continuous function of the position of the control body 312 inside the mixing conduit 302.

In an alternative embodiment, of the control module 310, the control module 310 may be provided such that, when the control body 312 is at least partially inserted in the mixing conduit 302, a substantial flow path for the third mass flow is provided through the control body 312 by providing the control body 312 with a through hole. In one embodiment, this through hole provides the flow path for the third mass flow substantially parallel to the axis 315 of the mixing chamber.

The control body 312 may be shaped to provide a low and preferably minimal amount of drag for the third mass flow as it flows past the control body 312. Therefore, the control body 312 comprises a tip 314 at the upstream side of the control body 312. Other shapes for the control body 312 are also envisaged, such as a cone, blunted cone, a bi-conic, ogive, elliptical, parabolic, or any other shaped body that may provide low drag for the third mass flow.

In an additional embodiment of the ejector 100, the control module 310 is connected to the control module actuator 320, arranged to translate the control shaft 316 over an axis 315 of the mixing chamber. The control module actuator 320 is in turn connected to the holding unit 318 which is arranged to fixate the position of the control module actuator 320 relative to the mixing chamber 300. The control module actuator 320 may be of a pneumatic, hydraulic, mechanical, electromechanical type, any other type, or any combination thereof.

In an additional embodiment of the control module 310, the control shaft 316 may be arranged with an inner or outer thread and the control module actuator 320 may comprise an outer thread or a hole with an inner thread arranged to engage with the thread of the control shaft 316.

In yet another embodiment of the ejector 100, at least one of the mixing conduit 302 and the control body 312 are arranged to translate relative to each other. In this embodiment, the mixing conduit 302 may be arranged to be translated over the ejector axis 101. A different embodiment of the ejector 100 may be envisaged in which the control body 312 is provided in the mixing conduit 302 from the upstream side. In this embodiment, the control body 312 may even be provided from a control module 310 provided upstream of the first motive nozzle module 200. Furthermore in this embodiment, the control shaft 316 may be arranged as one or more rods attached to the control body 312.

Fig. 5A shows an embodiment of a vapour-compression refrigeration system 400, comprising the ejector 100 according to any of the previously described embodiments, a liquid/gas separator 440, a compressor 450, an expansion valve 430, a condenser 410 and an evaporator 420. The liquid/gas separator 440 is arranged to separate a gas phase 441 from a liquid phase 442 of the refrigerant.

The ejector 100, arranged to be used in the vapour-compression refrigeration system 400, is of one of the abovementioned embodiments. Also possible is an ejector 100 comprising one, two or all of the following features: the ability to control the minimal flow-through area of the first mass flow by inserting additional motive nozzle modules in the first motive nozzle module 200, the ability to control the flow-through area for the third mass flow through the mixing chamber 300, and the ability to control the distance between the operated motive nozzle and the mixing chamber 300. Also, the one, two or all of the features here above mentioned may be arranged to work independently of each other, e.g. depending on the amount of flow flowing through the ejector 100.

When operating the ejector 100 at a low load, at least one of the following configurations of the ejector 100 may be chosen: a smaller motive nozzle opening, a smaller distance between the motive nozzle and the mixing chamber 300, and a smaller flow-through area for the third mass flow, or any combination thereof. Also, a configuration of the ejector 100 with two of the abovementioned elements may be chosen. When operating the ejector 100 at a high load, at least one of the following configurations of the ejector 100 may be chosen: a larger motive nozzle opening, a larger distance between the motive nozzle and the mixing chamber 300, and a larger flow-through area for the third mass flow, or any combination thereof. For operating the ejector 100 at any load between the low load and the high load, an optimal configuration may be found with any motive nozzle, a distance between the motive nozzle and the mixing chamber 300 between the minimal distance and the maximum distance, and a flow-through area for the third mass flow between the small flow-through area and the large flow-through area.

An additional embodiment of the vapour-compression refrigeration system 400, as shown in Fig. 5B, comprises a refrigeration system control module 460 and one or more sensors 461, in which the refrigeration system control module 460 is arranged to control at least one of the functionalities abovementioned. The one or more sensors 461, arranged to e.g. measure mass flow, temperature, pressure, heat flow, another parameter of the refrigeration system 400, or a combination thereof at a particular position, may be provided on different positions in the refrigeration system 400. The sensors 461 may be positioned anywhere in the refrigeration system, e.g. in the first mass flow, in the second mass flow, in the third mass flow, and after the evaporator as indicated in Fig. 5B. The refrigeration system control module 360 is arranged to receive a sensor signal 462 from the sensors 461, and use that sensor signal 462 to provide a control signal 463 to the ejector 100. The control signal 463 received by the ejector 100 may be used to at least one of insert or retract one or more motive nozzle modules, change the distance between the operated motive nozzle and the mixing chamber 300, and change the position of the control body 312 inside the mixing chamber 300. The control signal 463 may comprise one, two, three or more separate control signals for the motive nozzle module insert actuator 202, the control module actuator 320, and the motive nozzle module actuator 254.

Another embodiment of the refrigeration system 400 comprises multiple ejectors 100, arranged in parallel. In this embodiment, depending on the working load of the refrigeration system 400, the amount of operated ejectors can be controlled, as well as the different operating parameters of each ejector.

In the description above, it will be understood that when an element such as layer, region or substrate is referred to as being “on” or “onto” another element, the element is either directly on the other element, or intervening elements may also be present. Also, it will be understood that the values given in the description above, are given by way of example and that other values may be possible and/or may be strived for.

Furthermore, the invention may also be embodied with less components than provided in the embodiments described here, wherein one component carries out multiple functions. Just as well may the invention be embodied using more elements than depicted in the Figures, wherein functions carried out by one component in the embodiment provided are distributed over multiple components.

It is to be noted that the figures are only schematic representations of embodiments of the invention that are given by way of non-limiting examples. For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described. The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words 'a' and 'an' shall not be construed as limited to 'only one', but instead are used to mean 'at least one', and do not exclude a plurality. A person skilled in the art will readily appreciate that various parameters and values thereof disclosed in the description may be modified and that various embodiments disclosed and/or claimed may be combined without departing from the scope of the invention.

It is stipulated that the reference signs in the claims do not limit the scope of the claims, but are merely inserted to enhance the legibility of the claims.

In summary, an ejector is provided comprising a motive nozzle module, arranged to provide a first mass flow, and comprising a first motive nozzle, a suction chamber and a mixing chamber, provided downstream of the motive nozzle module and the suction chamber, arranged for mixing mass from the first mass flow and the second mass flow into a third mass flow. In this ejector, the mixing chamber and the first motive nozzle are arranged to translate relative to each other over an axis of the ejector for adjusting a distance between the first motive nozzle and the mixing chamber. This ejector allows controlling of a distance between the first motive nozzle and the mixing chamber. As a result, the location in the mixing chamber at which the shock wave occurs may be controlled.

Claims (16)

An ejector, comprising: - A motive nozzle module, arranged to provide a first mass flow, and comprising a first motive nozzle, provided on a downstream side of the motive nozzle module, - A suction chamber, arranged to provide a second mass flow ; and - A mixing chamber, provided downstream of the motive nozzle module and the suction chamber, arranged for mixing mass of the first mass flow and the second mass flow into a third mass flow, wherein the mixing chamber and the first motive nozzle are adapted to translate relative to from each other about an axis of the ejector for adjusting a distance between the first motive nozzle and the mixing chamber. The ejector of claim 1, wherein the motive nozzle module is adapted to translate between a first position and a second position, wherein the ejector is provided with a first stop that defines the first position and a second stop that defines the second position. The ejector according to claims 1-2, wherein the motive nozzle module is arranged to translate about the axis of the ejector. The ejector according to any of the preceding claims, wherein - The motive nozzle module comprises a flange extending outward from the motive nozzle module, and - The ejector comprises a housing, which further comprises a flange chamber, wherein the flange chamber comprises: . A downstream fluid chamber; ii. An upstream fluid chamber; iii. A downstream wall; and iv. An upstream wall, and wherein the housing is arranged to limit the axial translation of the motive nozzle module flange between the upstream wall and the downstream wall. The ejector of claim 4, wherein - The downstream fluid chamber chamber comprises a downstream fluid chamber inlet. The ejector of claims 4-5, wherein - The upstream fluid chamber chamber comprises an upstream fluid chamber inlet. The ejector according to claims 4-6, wherein - The upstream liquid chamber inlet is in communication with the first mass flow The ejector according to claims 4-7, wherein - The upstream fluid chamber inlet is in communication with the first mass flow. The ejector of claims 4-8, wherein - The downstream fluid chamber comprises a downstream fluid chamber outlet. The ejector according to claims 4-9, wherein - The upstream fluid chamber comprises an upstream fluid chamber outlet. The ejector of any one of claims 4-9, wherein at least one of the downstream fluid chamber and the upstream fluid chamber is connected to an external fluid source. The ejector as claimed in claims 2-3, wherein the motive nozzle module comprises one or more punches and / or racks adapted to provide an axial translation of the motive nozzle module. The ejector as claimed in claims 2-3, wherein the motive nozzle module comprises one or more threads arranged for providing an axial translate of the motive nozzle module. The ejector as claimed in claims 2-3, 12-13, wherein the ejector comprises an actuator adapted to translate the motive nozzle module, wherein the actuator is one of a mechanical, hydraulic, pneumatic and electromechanical type. The ejector according to any of the preceding claims, wherein the mixing chamber is adapted to translate over the axis of the ejector. A cooling system comprising: - An evaporator; - a compressor; - a capacitor; - an expansion valve; - Preferably, a liquid separator; and - An ejector according to any of the preceding claims.