JPS6093299A - Heat exchanger - Google Patents

Abstract

PURPOSE:To prevent the deterioration of flow amount distribution of primary fluid, flowing through primary fluid parallel flow paths, and permit the temperature of structure of heat exchanger or follow a sudden temperature change generated in the primary fluid upon low flow amount by providing a float, capable of being displaced by the flow resistance of the primary fluid, at the entrance of the parallel flow paths. CONSTITUTION:The communicating hole 22' of a float plate 22, provided at the upper side of the flow regulating plate 16 of a flow path 20b formed by a flow path forming body 19 and an outer shroud 10, is bored at a different position from the communicating hole 16b of the flow regulating plate 16 and the communicating holes are closed mutually when the float plate 22 contacts with the flow regulating plate 16. However, a very small part of the communicating hole is being opened at all times and capable of coping with the reverse flow of small flow amount or drain in the flow path. When fluid flows into an empty chamber 18 and the flow amount thereof is small, a pressure difference between the upper and lower surfaces of the flow regulating plate 16 is small and the float plate 22 continues a condition of being contacted with the flow regulating plate 16, most of the fluid flows through the flow path 20a formed by the outer cylinder 1 and the flow path forming body 19 and flows into an inlet window 12. When the flow amount exceeds a given value, the float plate 22 a floats and the fluid flows into the flow path 20b also.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a heat exchanger, and particularly to improve the temperature tracking of heat exchanger constituent members that are subjected to severe thermal transient phenomena, and to ensure the strength and integrity of the heat exchanger components. The present invention relates to a heat exchanger equipped with a self-regulating primary fluid rectifying means suitable for use in the present invention.

[Background of the invention]

As shown in FIG. 1, a conventional heat exchanger includes an outer shell 1 having an inlet nozzle 2 and an outlet nozzle 6 for primary fluid, an inlet window 12 housed in the outer shell, and an inlet window 12 in the upper part, and an inlet window 12 in the lower part. It consists of an outer shroud 10 having an exit window 13 at each side, and heat exchanger tube bundles 9 housed in the outer shroud 10 and attached to the upper and lower tube plates 4 and 8, respectively. On the earthen pipe plate 4, there is a pipe 2 having an outlet nozzle 7 for the secondary fluid.
The next-side upper end plate 3 is integrally coupled to form a secondary-side upper solenum 5. Upper plenum 51 upper end plate 3. The lower end of the secondary fluid inlet pipe 15 passing through the upper and lower tube plates 4.8 opens into the secondary lower solenum 14 formed by the secondary lower end plate integrally connected to the lower tube plate 8. ing.

Further, a shielding plate 11 is provided above the external shroud 10 and near the lower tube plates 4 and 8.

In the heat exchanger configured as described above, the high temperature fluid on the fc primary side is introduced from the primary fluid inlet nozzle 2 into the outer shell 1 circle, and the high temperature fluid on the fc primary side is passed from the inlet window 12 of the outer shroud lO to the outer shroud 1.
After flowing into the heat exchanger tube bundle 9 and descending while exchanging heat with the secondary fluid rising within the heat transfer tube bundle 9, it passes through the outlet window 13 and flows out of the device from the primary fluid outlet nozzle 6 of the outer shell 1. On the other hand, the low-temperature secondary fluid flows into the equipment through the inlet pipe 15, reaches the secondary lower plenum 14, where it is reversed, flows into the heat transfer tubes of the conduction tube bundle 9, and flows outside the heat transfer tubes. The fluid rises while exchanging heat with the primary fluid, reaches the secondary side upper plenum 5, and further flows out of the device from the secondary fluid outlet nozzle 7.

In the heat exchanger described above, as shown in FIG.
A rectifier plate 16 having a large number of flow holes in a cavity 18 formed by a solid plate 17 integrally connected to an external shroud 10 and a clay pipe plate 4 and in the vicinity of the primary fluid entry nozzle 2.
is provided protrudingly, and this current plate 16 is connected to the outer shroud 1.
It is fixed to the outer peripheral surface of the inlet nozzle 2 and serves to adjust the circumferential flow distribution of the primary fluid flowing in from the inlet nozzle 2 to make it uniform.

An arbitrary number of inlet windows 12 are provided in the circumferential direction in the upper part of the external shroud 10, that is, in the outer shroud between the solid plate 17 and the rectifying plate 16, and the primary fluid is transmitted through the inlet windows 12. guided to the heat tube bundle.

Furthermore, a flow path forming body 19 extending in the longitudinal direction and the circumferential direction is arranged in the empty chamber 18, and this flow path forming body is connected to the rectifying plate 16.
is fixed. Due to the arrangement of the flow path forming body 19, the primary fluid flowing within the cavity 18 can flow between the body 1 and the flow path forming body 19.
The flow is divided into a flow path 20a formed by a flow path 20a, a flow path 20b formed by a flow path forming body 19, and an external shroud 10,
The primary fluid rising in the flow path 20 & formed by the body 1 and the flow path forming body 19 hits the solid plate 17 and is reversed before flowing into the inlet window 12 of the outer shroud. As a result, if a temperature change occurs in the primary fluid flowing in from the inlet nozzle 2, heat is exchanged by the heat transfer tube bundle 9, and the secondary output fluid flows through the upper tube plate 4, so the upper tube The plate 4 expands or contracts in accordance with the temperature change of the primary fluid. Correspondingly, the temperature followability of the solid plate 17 connected to the clay pipe plate 4 improves, and the upper tube plate 4 and the solid plate 17 can be prevented from being subjected to large thermal stress.

However, the flow path 20 composed of the body 1 and the flow path forming plate 19
The resistance of & is greater than the resistance of the flow path 20b composed of the flow path forming plate 19 and the external shroud 10, so at low flow rates where a sudden temperature change occurs in the primary fluid, the flow rate of the former flow path is The drop becomes larger than that in the latter flow path, stratification of the temperature of the primary fluid in the cavity 18 occurs, and the ability of the upper tube plate 4 and the solid plate 17 to follow the temperature of the primary fluid deteriorates. There is a fear. In order to prevent the above situation as much as possible, the number of flow holes 16m in the current plate 16 is adjusted, and the flow path 20b composed of the flow path forming body 19 and the external shroud 10 is
It is also possible to increase the resistance, but in this case, the flow distribution in the circumferential direction of the cavity 18 becomes non-uniform and the pressure loss during steady operation becomes large.

[Purpose of the invention]

It is an object of the present invention to provide an fc
Primary Fluid Prevents the flow rate distribution of the primary fluid in the parallel flow path from deteriorating, allowing the temperature of the heat exchanger structure to quickly follow sudden temperature changes that occur in the primary fluid at low flow rates. It is an object of the present invention to provide a heat exchanger equipped with a self-controlling rectifying means that ensures flow around a structure and does not affect the flow characteristics at high flow rate during steady state.

[Summary of the invention]

A feature of the present invention is that an external shroud containing heat transfer tube bundles attached to upper and lower tube plates is housed in an outer shell, and a flow path forming body is provided in a space between the outer shroud and the outer shell in the longitudinal direction and circumferential direction. a heat exchanger extending in the direction, the flow path forming body dividing the space into parallel flow paths for the primary fluid flowing into the external shroud, and having a perforated baffle plate at the inlet of the parallel flow path; A float that can be displaced by the flow resistance of the second fluid is disposed at the inlet of the parallel flow path, and this float cooperates with the perforated baffle plate to control the flow path of the inner flow path of the parallel flow path at low flow rates. The point is that the resistance is made larger than the flow path resistance of the outer flow path.

FIG. 3 schematically shows the principle of the present invention. As shown in the figure, the flow path branches from the middle and is arranged vertically in parallel flow path 2Qa.
, 20b and further merge in the downstream, and a part of the parallel flow paths 20a, 20b is provided with a rectifying plate 16 having rectifying holes 16a, 16b for equalizing the flow rate. , a float plate 22 is provided on one of the rectifying plates 16 of the parallel flow paths. This float plate 22 is subjected to flow resistance of the fluid, and depending on whether this flow resistance is smaller or larger than its own weight, it rests on or floats on the current plate 16, and when it is in contact with the current plate 16, the current flow plate 22 16 rectifying holes 16b are closed, and when floating, the rectifying holes 16b are opened. When the flow rate is low and the pressure difference across the rectifier plate 16 is small, the float plate 22 remains blocking the rectifier hole 16b of the rectifier plate, and the fluid flows only into the flow path where the float plate 22 does not exist. When the flow rate increases, the pressure difference between the upstream side and the downstream side of the current plate 16 increases, and the float plate 22 floats up from the current plate 16. Due to this floating, the rate of increase in the pressure loss in the flow path 20b on the side where the float plate 22 is provided is lower than before the float plate 22 floats. Figure 4 shows this in terms of the relationship between the flow rate and pressure loss in the flow path, and also the relationship between the total flow rate in the flow path and the flow rate in the flow path without a float plate and in the flow path with a float plate. The relationship is shown in Figure 5. The shaded area in FIG. 5 is the amount of improvement in flow distribution to both channels due to the provision of the float plate.

The present invention applies such a principle to the parallel flow path between the outer shell and the outer shroud of the heat exchanger.

[Embodiments of the invention]

An embodiment of the invention is shown in FIGS. 6 and 7.

The same parts as in the conventional example are indicated by the same reference numerals. Similarly to the above, the outer shell 1 of the heat exchanger and the outer shroud 10 of the heat exchanger tube bundle part
and a solid plate 17 connected to the upper tube plate 4.
8 includes a perforated current plate 16 fixed to the external shroud 10, and a perforated current plate 16 fixed to the perforated current plate 16, which divides the chamber 18 into two in the longitudinal direction and circumferential direction to form parallel flow paths 20a and 20b. A flow path forming body 19 extending therein is installed.

Now, in this embodiment, a float plate 22 is provided. The float plate 22 has a large number of flow holes 22' like the current plate 16, and has a flow path 20b formed by the flow path forming body 19 and the external shroud 10.
is provided above the current plate 16. The communication holes 22' of the float plate 22 are bored at different positions from the communication holes 16b of the current plate 16, and when the float plate 22 and the current plate 16 are in contact with each other, the communication holes are mutually blocked. However, in this case, the flow holes 16b of the current plate 16 are completely blocked, so
A very small number of the flow holes are always open to accommodate small flow rates such as backflow and drainage of the flow path.

With this structure, when fluid flows into the cavity 18, the pressure difference between the upper and lower surfaces of the current plate 16 is small when the flow rate is small.
Since the weight of the float plate 22 is greater than the force pushed up by this pressure difference, the float plate 22 remains in contact with the rectifier plate 16, and most of the fluid is formed by the outer shell 1 and the channel forming body 19. The liquid flows into the flow path 20&, passes over the upper end of the flow path forming body 19, flows around the solid plate 17 connected to the upper tube plate 4 and the earthen tube plate 4, and flows into the inlet window 12. When the flow rate flowing into the chamber 18 increases and exceeds a certain value, the pushing up force acting on the float plate 22 becomes larger than the gravity of the float plate 22, and the float plate 22
floats up, and the fluid also flows into the channel 20b provided with the float plate 22. When the flow rate increases further, the float plate becomes vacant 1
8, but the float plate guide mechanism 23 restricts floating beyond a certain level. In such a state, the pressure loss at the baffle plate 16 portion is not significantly different from that in the case where the float plate 22 is not provided, and there is little influence on the flow characteristics of the heat exchanger. The floating characteristics of the float plate 22 are determined solely by the flow rate of the fluid flowing through the cavity 18. The flow rate at which the float plate floats is determined by the weight of the float plate and the flow path resistance, but this can be arbitrarily set depending on the conditions of use.

Details of the float plate guide mechanism 23 are shown in FIG. This keeps the float plate 22 parallel to the current plate 16 during floating and prevents it from rotating in the circumferential direction, and at the same time, it remains immovable against fast repeated flow fluctuations and is as strong as possible against slow flow fluctuations. It is configured to have the function of a kind of damper that quickly follows. That is, the float plate guide mechanism includes a guide rod 24 that is fixed to the current plate 16 and passes through the float plate 22 and whose tip is larger than the float plate through hole, and a cylinder 25 that is fixed to the float plate 22. The rod 24 is inserted into the cylinder 25 with a small gap, and the cylinder 25 has a small hole 26 in its face.
The cylinder 25 is filled with fluid. Such float plate guide mechanisms 23 are installed at three or more locations in the circumferential direction of the rectifier plate 16. With the above structure, the float plate 22 floats stably, and is able to withstand rapid repeated flow rate fluctuations of fluid circulation pumps, etc. 8 shows another embodiment of the present invention. In this embodiment, a float plate 22 is provided in the flow path 20m in which the flow rate is desired to be kept low at low flow rates. In the previously described embodiment, the float plate 22 floats to open the flow port 16b of the current plate 16, whereas in this embodiment, the float plate 22 floats to open the flow port 16b of the current plate 16.
6& is provided at the lower part of the rectifying plate 16.

The flow ports of the current plate 16 are made such that the flow port 16a of the flow path 20a where the flow rate is to be ensured during low flow is larger, and the flow port 16b of the other flow path 20b is smaller. At low flow rates, the weight of the float plate 22 is greater than the drag force caused by the flow, so the float plate 22 is at the lower end position, and the rectifier plate 1
The flow port 16a of No. 6 is completely opened. therefore,
A large amount of fluid flows into the flow path 20m on the side of the flow port 16a, where the opening area of the rectifying plate 16 is large and the flow path resistance is low. When the flow rate is high, the float plate 22 floats due to the fluid flowing therethrough, thereby restricting the flow opening 16a of the current plate 16. Therefore, the water also flows into the flow path 20b on the side of the flow chamber 16b.

In this case, the opening of the flow port 16b can be set in advance so as to uniformly distribute the flow rate in the circumferential direction, so that it does not affect the flow characteristics at all.

As a result, the same effects as shown in the previous embodiment can be obtained, and depending on the type of heat exchanger, it is possible to improve the accessibility and the workability of maintenance and repair.

FIG. 9 shows another embodiment of the present invention in which the means for adjusting the opening of the flow port 16b of the flow path 20b of the flow path 20b shown in FIGS. 6 and 7 is modified. In the embodiments shown in FIGS. 6 and 7, the flow opening 16b of the current plate 16 and the flow hole 22 of the float 22 are
' and are placed in a position that does not overlap with each other to block the flow port 16b.

FJ the opening! It was a four-way adjustment. In the embodiment shown in FIG. 9, a protrusion 27 is attached to the float 22, and the protrusion 27
is inserted into the flow port 16b of the current plate 16. The protrusion 27 and the flow opening 16b of the rectifying plate are provided with tenor plates so that the opening area changes depending on the relative displacement between the float 22, the protrusion 27, and the rectifying plate 16. Thereby, the change in the flow path area due to the movement of the float 22 can be made gentler, and the stability of the operation can be maintained. In addition, the distribution port 16
Since the position of the protrusion 27 coincides with the position of the protrusion 27, the opening of the flow port can be changed over a wide range, which has the advantage of widening the range of application.

〔Effect of the invention〕

According to the present invention, it is possible to prevent deterioration of the flow r-distribution at low flow rates for two parallel primary fluid flow paths separated by a flow path forming member in the outer shell of the heat exchanger and the outer shroud space. As a result, it is possible to secure the flow around the tube plate of the heat transfer tube bundle and the solid plate connected thereto so that it can quickly follow the temperature change of the primary fluid at low flow rates. Moreover, it has the advantage that it does not affect the flow characteristics at high flow rates and has a simple structure.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views showing the configuration of a conventional heat exchanger, Figure 3 is an explanatory diagram of the operating principle of the present invention, and Figures 4 and 5 are explanatory diagrams of the flow characteristics according to the present invention. , FIG. 6 is a sectional view showing an embodiment of the present invention, FIG. 7 is a partially detailed view of the embodiment,
FIGS. 8 and 9 are sectional views of other different embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... Body, 2... Nozzle, 4... Upper tube plate, 8... Lower tube plate, 9... Tube bundle, 10... External shroud, 12...
・Entrance window, 13... Exit window, 16... Rectifier plate,
16a... Distribution hole, 17... Solid plate, 18...
Vacancy, 19... Channel forming body, 22... Float plate, 23
...Float plate guide mechanism, 24...Guide rod, 25...Cylinder. Fig. 1 Fig. 2 Fig. 3 Low 5 Danger level High;

Claims (1)

[Scope of Claims] 1. An external shroud containing a bundle of heat transfer tubes attached to the upper and lower tube plates is housed in the outer shell, and extends longitudinally and circumferentially within the space between the outer shroud and the outer shell. In a heat exchanger in which the space is divided into parallel flow paths for the primary fluid flowing into the external shroud by a flow path forming member, and a perforated baffle plate is provided at the inlet of the parallel flow paths, the flow resistance of the primary fluid is reduced. A float that is displaceable by the perforated rectifying plate and cooperates with the perforated baffle plate to make the flow resistance of the inner flow path of the parallel flow path larger than the flow resistance of the outer flow path at low flow rates is provided at the entrance of the parallel flow path. A heat exchanger characterized by being provided in. 2. The heat exchanger according to claim 1, wherein the float is provided on the downstream side of the baffle plate in the inner flow path. 3. The heat exchanger according to claim 1, wherein the float is provided on the upstream side of the baffle plate in the outer flow path. 4. Claims 1, 2, or 4, in which the float is supported via a damper that does not respond to rapid repeated fluctuations in flow rate and displaces the float only to large fluctuations in flow rate. Heat exchanger according to item 3.