Air condensers for organic Rankine cycle plants.

Abstract

The air condenser (100) suitable for an organic Rankine cycle plant operated by a working fluid comprises a tube bundle (80) having two pitches, a support structure (110) that allows the tube bundle (80) to be arranged at an angle, an air duct (120) passing through the tube bundle (80), and at least one fan (130) that draws air and exchanges heat with the working fluid to be condensed. The first pitch (10) of the tube bundle (80) has a plurality of first tubes and condenses the working fluid to a vapor content greater than zero. The second pitch (14) of the tube bundle (80) has a plurality of second tubes and has an upstream first end (14') and a downstream second end (14"), and condenses only the remaining vapor flow of the working fluid that was not condensed in the first pitch (10). The second pitch (14) is inclined upward to allow non-condensable gases present in the working fluid to be discharged through the second end (14").

Description

[Technical Field]

[0001] The present invention relates to an air condenser for an organic Rankine cycle plant.The innovative air condenser solution is particularly suitable for non-cogeneration organic Rankine cycle plants. [Background technology]

[0002] A thermodynamic cycle is defined as a finite series of thermodynamic transformations (e.g., isothermal, isochoric, isobaric, or adiabatic) at the end of which the system returns to its initial state.

[0003] The cycle may be a direct cycle, such as a direct Rankine cycle, in which a heat source is used to generate mechanical or electrical energy and heat at a lower temperature than the heat source.

[0004] The ideal Rankine cycle is a thermodynamic cycle that includes, among other things, two adiabatic and two isobaric transformations. In the case of a direct cycle, the purpose of the cycle is to convert heat into work. The cycle is commonly employed in thermoelectric power plants, especially for generating electricity. The cycle uses water as the working fluid, both in liquid and vapor form, and is used with so-called steam turbines.

[0005] More specifically, organic Rankine cycles (ORCs) have been hypothesized and created. Organic Rankine cycles use high-molecular-weight organic fluids for a variety of applications, particularly those utilizing low- to medium-enthalpy heat sources. Similar to other steam cycles, the equipment for an organic Rankine cycle includes one or more pumps to supply the organic working fluid, one or more heat exchangers, a steam turbine for fluid expansion, a condenser to return the organic working fluid to a liquid state, and an optional regenerator. The one or more heat exchangers perform preheating and evaporation, and optionally a superheating or heating step under supercritical conditions of the working fluid. The steam turbine is mechanically connected to a generator. The regenerator recovers heat downstream of the turbine and upstream of the condenser.

[0006] Many ORC plants use organic fluid turbine generators to generate energy from renewable energy sources or industrial heat recovery. In such ORC plants, the cycle condenser includes an air condenser. In combined heat and power applications, the condensation temperature is maintained high enough to satisfy heat users. The condenser is preferably cooled by water. Water is a more efficient heat carrier for transferring heat from generation to users and also for transferring heat over long-distance distribution networks, such as district heating networks.

[0007] On the other hand, in non-cogeneration applications, there is no need to utilize the heat released by the condenser. However, it is necessary to release this heat to the environment at the lowest possible temperature (i.e., at a small temperature difference with respect to the ambient temperature). For this reason, air condensers are used, which usually have a series of condensation tubes arranged in parallel. In such air condensers, condensation takes place in the tubes and in cooling air driven by a fan that strikes the condensation tubes transversely.

[0008] In many applications, the total amount of fluid to be condensed is distributed among a number of bays of the condenser, each of which may have one or more tube bundles.

[0009] 1 and 2, known methods used to condense organic fluids in ORC plants can be described assuming a single tube bundle, since the operating conditions of the single tube bundle are representative of the overall function of the condenser.

[0010] 1 is a schematic diagram of a tube bundle 50 having one pitch. The entire volume of working fluid to be condensed associated with the tube bundle passes through the supply tube 21 and flows into the inlet manifold 16. This flows into a number of parallel tubes, proceeding from left to right and top to bottom in FIG. 1. The tubes constitute a single pitch 22 of the tube bundle 50. In practice, the tube bundle is installed at a certain inclination to facilitate liquid drainage.

[0011] Outside the tube bundle, one or more fans (not shown) blow air (indicated by arrows 19) across the tube surfaces of the tube bundle in a transverse direction under ambient conditions. Typically, the outer surfaces of the tubes are provided with fins, for example, aluminum fins wrapped around the tubes to improve exchange with ambient air.

[0012] As steam passing through the steam passages in the tubes condenses, a condensed liquid stream is produced that is collected at the tube outlet in outlet manifold 17 and then pumped by a feed pump (not shown) back into the ORC plant circuit via pipe 18.

[0013] The single-pitch condenser or tube bundle approach, while simple, has inherent drawbacks related to the condensate being overcooled to a measurable degree relative to the condensation temperature of the vapor. Indeed, all vapor must condense within a single pass (pitch) of the tube bundle. This means that there must be zero vapor at the exit of each tube. To further ensure zero vapor content, only liquid flows through the last section of the tube bundle. The liquid is further cooled by contact with the cold tube surfaces (whose temperature is closer to the ambient air temperature rather than the condensation temperature of the vapor). This results in overcooling of the liquid. This is especially true for liquid flowing through the bottom row of tubes, which are the first to be hit by air at ambient temperature. The air is not heated by crossing the tube bundle.

[0014] There are several practical methods known to reduce excessive cooling. For example, the number of fins on the outer surface of the tubes in the lower rows of the tube bundle can be reduced. These are the rows that are exposed to the coldest air. However, this type of single-pitch method does not significantly reduce the aforementioned phenomenon, since, as mentioned above, there must be zero vapor at the tube exit. Therefore, there is still only liquid near the tube exit, which will still experience the aforementioned excessive cooling.

[0015] The presence of non-condensable gases further exacerbates the above-mentioned phenomenon. Therefore, ORC plants often include a non-condensable suction system 20 for single-pitch systems. The non-condensable suction system 20 is usually located at the top of the outlet manifold.

[0016] Excessive cooling of the liquid is a significant problem because it reduces the overall efficiency of the thermodynamic cycle. The excess heat must be supplied to the working fluid from the heat source. Therefore, part of the heat input to the thermodynamic cycle is used to compensate for the removal of the "unwanted" heat generated in the condenser.

[0017] Figure 2 shows a two-pitch tube bundle approach in which the problem of overcooling is almost completely solved. The tube bundle 60 includes a supply pipe 21, an inlet manifold 1, a first pitch 7 consisting of a first plurality of tubes, an intermediate manifold 2 where the liquid phase is separated, and a second pitch 4 consisting of a second plurality of tubes. The second plurality of tubes processes only the remaining vapor flow that was not condensed in the first pitch. Therefore, the liquid condensed in the first pitch is not overcooled. At the outlet from the first pitch, the vapor content is still not zero, there is an equilibrium between the liquid and vapor phases, and the temperature is the condensation temperature of the vapor. Therefore, there is virtually no overcooling of the liquid exiting the first pitch. The condensate from the second pitch is collected in the outlet manifold 5 and discharged through nozzle 6. The second pitch may produce overcooled liquid. However, the amount of this liquid is very small compared to the total volume. This is because most of the liquid is removed from the intermediate manifold 2 through nozzle 3.

[0018] In this method, to effectively remove non-condensables (designated NCG in Figure 2), it is necessary to extract them from both the intermediate manifold 2 and the outlet manifold 5. In the outlet manifold 5, the steam flow rate is essentially zero, and the condensate in the second pitch is discharged. This allows the non-condensables to accumulate and be conveniently discharged. In contrast, in the intermediate manifold 2 in the two-pitch method, the steam content is not zero, and the working fluid still in the vapor phase is also discharged together with the non-condensable gases. On the other hand, since non-condensable gases may remain "trapped" in this area of ​​the condenser, it is also justified to discharge this area. This discharge would delegate the separation of any organic fluids drawn in to an external specific separator.

[0019] In addition to the more complicated drainage of noncondensables, this approach also has other drawbacks, primarily related to cost and size. In both pitches, the tubes must be tilted to drain the liquid. In the single-pitch approach shown in Figure 1, the tube bundle 50 consists of straight, parallel tubes, with the tilt left to the support structure. In the dual-pitch approach shown in Figure 2, the tube bundle 60 is generally horizontal, but the tubes at the first pitch 7 and the second pitch 4 must be tilted in opposite directions. This significantly increases the overall height of the tube bundle. For example, the tubes may be 18 meters long and have a 2-degree tilt, resulting in a height difference of approximately 0.6 meters between the inlet and outlet ends of each row of tubes. The height of the tube bundle is at least 0.6 x 2 = 1.2 meters, due solely to the need for opposite tube tilts. Furthermore, because liquid accumulates in the two manifolds 2 and 5, which are quite far apart, two "plumbing" lines are required to remove the liquid. Summary of the Invention [Problem to be solved by the invention]

[0020] Therefore, there is a need for an air condenser design that overcomes or at least mitigates the aforementioned drawbacks. [Means for solving the problem]

[0021] The solution to the technical problem mentioned in the previous paragraph is achieved according to the present invention by an air condenser for an ORC plant. The air condenser comprises a tube bundle having two pitches. In the tube bundle, condensation of the working fluid takes place in the first pitch until the vapor content is always greater than zero. In the second pitch, only the remaining vapor flow of the working fluid that was not condensed in the first pitch is condensed. The second pitch is inclined upward. The second pitch is provided with openings for discharging non-condensable gases. The second pitch is located above and parallel to the first pitch.

[0022] According to one aspect of the present invention, an air condenser for an organic Rankine cycle plant is described, which has the features set out in the independent claims attached hereto.

[0023] Further preferred solutions and / or particularly advantageous ways of implementing the installation are described by the features set out in the attached dependent claims. [Brief explanation of the drawings]

[0024] The invention will now be described with reference to the accompanying drawings, which show non-limiting examples of implementation of an air condenser.

[0025] [Figure 1] FIG. 1 is a schematic diagram showing an example of a single-pitch tube bundle of an air condenser according to the known art. [Figure 2] FIG. 2 is a schematic diagram showing an example of a tube bundle with two pitches of an air condenser according to the known art. [Figure 3] FIG. 3 is a schematic diagram showing a two-pitch tube bundle of an air condenser according to one embodiment of the present invention. [Figure 4a] 4a and 4b are schematic diagrams showing two pitched tube bundles of an air condenser according to two further embodiments of the present invention. [Figure 4b] 4a and 4b are schematic diagrams showing two pitched tube bundles of an air condenser according to two further embodiments of the present invention. [Figure 5] FIG. 5 is a schematic diagram showing the two-pitch tube bundle of FIG. 3 integrated into an air condenser. [Figure 6] FIG. 6 is a schematic diagram showing a first solution for defining a compartment dedicated to the transport of condensate. [Figure 7] FIG. 7 shows a detailed diagram of the solution of FIG. [Figure 8] FIG. 8 is a schematic diagram showing a second solution for defining a compartment dedicated to the transport of condensate. DETAILED DESCRIPTION OF THE INVENTION

[0026] 3-5, a two-pitch tube bundle 80 for an air condenser 100 for an ORC plant includes at least a supply tube 21 (only one in the exemplary illustration), an inlet manifold 11, a first pitch 10 with a plurality of first tubes, an outlet manifold 12, and a second pitch 14 with a plurality of second tubes. In the first plurality of tubes, the working fluid is condensed so that the vapor content is always greater than zero. In the outlet manifold 12, separation of the liquid phase takes place. The liquid phase is discharged through at least one nozzle 13 (only one in the exemplary illustration) and sent to a condensation manifold 13a (shown in FIG. 6). In the second plurality of tubes, only the remaining vapor flow not condensed in the first pitch is processed.

[0027] According to the present invention, the second pitch 14 is preferably arranged along a position above and parallel to the position of the first pitch.

[0028] Furthermore, the second pitch ends with a further manifold 15. The role of the manifold 15 is to accumulate non-condensable gases (NCG). This role is based on the fact that the further manifold 15 represents: - the highest point of the tube bundle 80, which is therefore suitable for accumulating a non-condensable gas having a lower density than the working fluid vapor. -It's a very peaceful space. -A very effective area for the discharge of non-condensable gases from the process.

[0029] So, on the second pitch 14, the following happens: Condensation occurs of the remaining steam flow that was not completely condensed during its passage through the first pitch 10. The steam moves upward through the pipes because it is pushed up by the low pressure present in the further manifold 15 or by the positive pressure difference that exists between the first upstream end 14' of the second pitch 14 and the second downstream end 14" of the second pitch 14. The remaining condensate flows downwards by gravity into the outlet manifold 12 where it is discharged.

[0030] Advantageously, since the condensate is discharged only through at least one nozzle 13, a double "piping" system for returning the condensate to the ORC plant is not required. If the second pitch 14 is located above the first pitch, a suitable location for discharging non-condensable gases becomes available, namely the second end 14" of the second pitch 14. In fact, this end is the upper part of the condenser, where the concentration of non-condensable gases is high. Therefore, no condensate is discharged from the second pitch 14 (more precisely, from the second end 14"), but only non-condensable gases. In this case, the proportion of working fluid in the vapor state can be reduced.

[0031] This occurs even when the tube bundle 80 has the same advantages as the known solution shown in Figure 2, namely that any excessive cooling of the liquid is substantially avoided. Indeed, in the case of the known solution with two pitches of Figure 2, when the vapor content is greater than zero, excessive cooling is minimized by the fact that part of the condensate is discharged at the outlet of the first pitch 10 and that the rows of tubes of the second pitch 14 are exposed to the warm air located above the first pitch (and not directly exposed to room temperature air, as in the example of Figure 2).

[0032] To facilitate liquid drainage, the entire bundle of parallel tubes is mounted at an angle by the support structure 110 of the condenser 100, as in the single-pitch configuration shown in FIG. 1, as opposed to the double-pitch configuration shown in FIG. 2.

[0033] Thus, the tube bundle 80 of the present invention is just as compact as a configuration having one pitch, since it does not need to accommodate rows of tubes with opposing slopes therein.

[0034] Alternatively, the tube bundle 80 can comprise a second pitch 14 below the first pitch 10 or in parallel with the first pitch 10. Solutions such as that shown in Figure 4a are also possible. In Figure 4a, the tube bundle 80 comprises a second pitch 14 below the first pitch 10.

[0035] Furthermore, hybrid solutions are also possible, such as that shown in Figure 4b. This is useful when the temperature difference between the air and the working fluid is very large, and the vapor content exiting the first pitch can be nearly zero. In this case, the second main pitch 14 is located below and parallel to the first pitch 10, and a partial second auxiliary pitch 114 is located parallel to the upper row of the first pitch 10. For example, the upper row is created with a total number of tubes of n, the number of tubes in the second pitch of y, and the number of tubes in the first pitch of ny (e.g., y = 2). Non-condensable gases are discharged through a first manifold 15' at the end of the second main pitch 14 and a second manifold 15' at the end of the second auxiliary pitch 114.

[0036] The second main pitch 14 is located below the first pitch 10 and has the advantage of preheating the air. In this way, the air that reaches the rows of tubes below the first pitch (which has already hit the second pitch 14) is already preheated. This prevents all of the steam leaving the first pitch from condensing. This prevents the steam from condensing too quickly and creating pockets where non-condensable gases can become trapped in the liquid.

[0037] At the same time, the second pitch 114 is positioned parallel to the upper row of the first pitch 10, maintaining the aforementioned advantage of locating the second pitch in the most suitable position for collecting non-condensable gases, which are lighter than the working fluid vapor and therefore stagnate at the top of the manifold of the first pitch.

[0038] 5, the air condenser according to the present invention includes the tube bundle 80, a support structure 110 that allows the tube bundle 80 to be tilted, an air duct 120 that passes through the tube bundle 80, and a fan 130 that draws in the air that exchanges heat with the condensing working fluid. The temperature at the outlet of the air duct 120 may be slightly higher than the ambient temperature.

[0039] After coming up with this solution, the author also solves further potential technical problems that may accompany it. In fact, in the second pitch, the steam and liquid have opposite directions, which may cause the steam to interfere with the drainage of the pipes. Finite element fluid dynamics analysis does not provide any evidence of this problem. However, the author believes it is appropriate to propose some solutions in case the actual fluid behavior differs from that in the simulation.

[0040] The solution to this problem is to define a section 141 in the second pitch 14 transverse to the axis of the exchange tubes 140 of the second pitch 14. The section 141 is located at the bottom of the exchange tubes. In the section 141, mainly liquid collects.

[0041] 6 and 7, a non-limiting example cross section 141 is provided by a small drain 145. The drain 145 is axially positioned relative to the general exchange tube 140 of the second pitch 14, and is inserted into and rests on the exchange tube 140 with a parallel axis. Thus, the section 141 coincides with a straight portion of the small drain 145.

[0042] The small drain tube 145 has a first portion 146 that is inserted into the exchange tube 140 and terminates at the end 140' of the tube 140, and a second portion 146 that is continuous with the first portion and extends from the end 140' of the tube 140, terminating below the liquid head of the condensation manifold 13a.

[0043] The small drain 145 has a lower stiffness than the exchange tube 140 that contains it. The drain 145 has a diameter that is approximately one-third that of the exchange tube 140. The drain 145 features an opening 148 located substantially at the junction of the exchange tube 140 and the small drain 145. The opening 148 allows condensate to enter the drain 145.

[0044] The opening 148, which is the liquid inlet, is located below the head to ensure that only condensate, and not vapor, enters the small drain 145. This serves to separate the liquid phase from the vapor, which, as mentioned above, has the opposite orientation. The liquid entering the small drain 145 can descend under gravity due to the slope foreseen by the tube bundle 80, i.e., the same slope as the tubes that comprise the drain 145. This solution prevents vapor from entering the small drain 145 for two reasons. First, the tube end is located below the head, allowing only liquid to enter. Second, the opening 148 is not continuous along the entire length of the small drain 145. In fact, the opening is present only in the first section 146 of the small drain 145, the part inserted into the tube 140. On the other hand, the second portion 147 of the small drain 145 does not have any openings 148 to further ensure that steam does not enter the drain 145 .

[0045] In this way, the vapor rising countercurrently to the liquid is prevented from creating so-called pockets that would cause stagnation of the liquid in the drainage path, and as a result, excessive cooling of the liquid is avoided. A further advantage of this solution, in addition to the purely hydraulic advantages explained above, is that the condensate is protected from excessive cooling. This is because, considering the front part of the system, as a result of the geometry of this solution, the liquid that enters the small tube comes into contact with the exchange tube at only one point, namely the junction between the small tube and tube 140.

[0046] Advantageously, the length of the small drain 145 can be shorter, i.e., the drain 145 can include a single section that is inserted into the exchange tube 140, terminating short of the end 140′ of the exchange tube 140.

[0047] In fact, the liquid stagnation phenomenon caused by the thrust of rising steam generally occurs at steam velocities above a certain threshold. This threshold mainly depends on the type of fluid. However, steam condenses in the second pitch, slowing its velocity along the way. Therefore, it is possible to consider defining the length of the small drain 145 so that it only reaches the "critical" part, i.e., the part affected by the fast steam. In this way, the small drain 145 only affects a portion of the exchange tubes 140 in the second pitch. In other words, the axial length of the small drain 145 is shorter than the axial length of the exchange tubes 140.

[0048] This solution has several advantages over the previous solutions. Smaller tubes are lighter and therefore less costly. - The risk of kinking and deformation of small tubes is reduced. - The small tubes are more likely to be kept below the liquid level at all times, thereby reducing the risk of steam getting inside the small tubes.

[0049] Any suitable attachment means can be used to secure the small drain 145 and restrain the drain 145 from moving axially downward.

[0050] Simple support on the exchange tube 140 may be sufficient to prevent axial sliding of the tube due to static friction.

[0051] Alternatively, the small tubes of the second pitch 14 can be fixed to each other directly or via internal structures and are integral with the wall of the condensation manifold 13a.

[0052] An alternative to the small drain pipe 145 is to insert a drain sheet 150 into the exchange tube 140 of the second pitch 14 to separate the liquid and the vapor. The drain sheet 150 keeps the transverse section 141, through which the condensate flows (downward), separate from the vapor region (where the vapor "blows" upward). This ensures that the liquid is not affected (or is affected to a significantly reduced extent) by the drag of the counterflowing vapor. In this case, the transverse section 141 is defined by the drain sheet 150 and the wall of the exchange tube 140 and is located below the drain sheet 150.

[0053] The drainage sheet is preferably a perforated sheet 150 that is inserted in a horizontal position onto the tubes 140 before the tubes 140 are attached to the second pitch 14 of the tube bundle 80. Advantageously, the perforated sheet 150 can be fixed by a fastening, for example the one shown in Figure 8, in order to hold it in the required position. The fastening shown in Figure 8 is obtained by a vertically oriented fastening sheet 160, which elastically deforms the horizontally oriented perforated sheet 150.

[0054] It should be understood that in addition to the embodiments of the present invention described above, there are many other variations. It is understood that the embodiments described above are merely illustrative and do not limit the scope, application, or possible configurations of the present invention. On the other hand, the foregoing description will at least enable one skilled in the art to practice the present invention in accordance with one of the exemplary configurations. However, it is understood that many variations of the described components can be conceived without departing from the scope of the present invention as defined in the appended claims.

Claims

1. An air condenser (100) suitable for an organic Rankine cycle plant operated by a working fluid, comprising: a tube bundle (80) having two pitches; a support structure (110) that allows for an inclined arrangement of the tube bundle (80); an air duct (120) passing through said tube bundle (80); at least one fan (130) for drawing air to exchange heat with the working fluid to be condensed; Equipped with a first pitch (10) of the tube bundle (80) having a plurality of first tubes for condensing the working fluid to a vapor content always greater than zero; a second pitch (14) of the tube bundle (80) having a plurality of second tubes, having an upstream first end (14') and a downstream second end (14"), for condensing only the remaining vapor flow of the working fluid not condensed in the first pitch (10); The second pitch (14) slopes upward; The second pitch (14) allows non-condensable gases present in the working fluid to be discharged through the second end (14"); At least one exchange tube (140) of the plurality of second tubes in the second pitch (14) is provided with a transverse section (141) located at a lower portion of the exchange tube (140) and transverse to an axis of the exchange tube (140) of the second pitch (14); In said transverse compartment (141) liquid is collected, The transverse section (141) is a transverse section of a small drain pipe (145) inserted into the exchange tube (140), placed on the exchange tube (140), and positioned along the axial direction of the exchange tube (140); The small drain pipe (145) is provided with an opening (148) at the contact point between the exchange tube (140) and the small drain pipe (145) to allow condensate to enter. Condenser (100).

2. 2. The condenser (100) of claim 1, wherein the second pitch (14) is located above and parallel to the first pitch (10).

3. 2. The condenser (100) of claim 1, wherein the second pitch (14) is located below and parallel to the first pitch (10).

4. The second pitch (14) is a main pitch and is located below and parallel to the first pitch (10); The partial second auxiliary pitch (114) is located parallel to the upper row of the first pitch (10). The condenser (100) of claim 1.

5. the tube bundle (80) has a manifold (15) downstream of the second end (14") of the second pitch (14); The manifold (15) is located at the highest point of the tube bundle (80) and is suitable for storing a non-condensable gas having a density less than that of the vapor of the working fluid. The condenser (100) of claim 1.

6. The condenser (100) according to any one of claims 1 to 5, wherein in the second pitch (14), a flow rate of the remaining condensate of the working fluid flows downward by gravity and into an outlet manifold (12).

7. 7. The condenser (100) of claim 6, wherein the tube bundle (80) has at least one opening (13) downstream of the outlet manifold (12) that allows the discharge of all liquid phases of the working fluid.

8. The small drain (145) a first portion (146) inserted into said exchange tube (140) and terminating at an end (140') of said exchange tube (140); a second portion (147) extending from the end (140') of the exchange tube (140) continuous with the first portion (146) and terminating below the liquid head of the condensate collecting portion (13a); having A condenser (100) according to any one of claims 1 to 7.

9. The condenser (100) of claim 8, wherein the opening (148) is present only in the first portion (146) of the small drain (145).

10. The small drain (145) has a single portion inserted into the exchange tube (140); The axial length of the portion is shorter than the axial length of the exchange tube (140). The condenser (100) of claim 8.

11. 11. The condenser (100) of claim 10, wherein the small drain (145) is integrated directly or via an internal structure into the wall of the condensate collector (13a).

12. The transverse section (141) is defined by a thin drainage sheet (150), The thin drainage sheet (150) separates the upward flowing residual vapor stream of the working fluid from the downward flowing residual condensate stream of the working fluid. A condenser (100) according to any one of claims 1 to 11.

13. 13. The condenser (100) of claim 12, wherein the thin drainage sheet is a perforated thin sheet (150) accommodated in the exchange tube (140) in a horizontal position.

14. 14. The condenser (100) of claim 13, wherein a vertically oriented fixing sheet (160) elastically deforms the perforated thin sheet (150) and fixes the perforated thin sheet (150) within the exchange tube (140).

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