DE2303788A1 - Flow distributor for heat exchanger head - producing uniform flow - Google Patents

Abstract

The system uses cooling air counterflow and has a head fitted with an inlet. Inside the head an inclined baffle plate is uniformly perforated and allows flow through to a collecting chamber below, where the now still liquid then escapes vertically via a mumber of outlets and ribbed pipes surrounded by the air current. Turbulent flow into the head is converted to a uniform flow through the system, which is effective for varying inlet rates.

Description

Heat exchanger tube bundle head flow distribution apparatus The invention relates to gas-liquid cooling devices such as upright, multiple, finned Tubular heat exchangers that have an overhead hot liquid head for distribution of the liquid to the individual finned agitators to create uniform flows of downflowing Durohfluss to achieve, thereby in indirect heat exchange be brought with a cooling gas flow.

A liquid cooler of the type described generally includes an upper, hot water collecting head, in which the hot liquid is fed or distributed around a uniform downward gravity flow through an area to allow a flow path of cooling ambient air cuts to cool the liquid. A uniform distribution of the liquid flow through the cooling area is necessary to achieve maximum operating efficiency in the Device. Great heat exchange efficiency is usually achieved, by a number of side-by-side, parallel, ribbed ones Tubing is used to cool the fluid in indirect heat exchange with to bring the cooling medium.

In a particularly important application of heat exchanger structures of this type, the fluid to be cooled consists of hot @ Water from partly the condenser of an electric power plant, and after / cooling down in the "dry" heat exchanger the water is collected and in a direct, Evaporative "wet" cooling tower section is further cooled before going to the condenser is returned.

The hot liquid flow to the overhead head of the dry one Heat exchanger is often turbulent in its kind due to the pump head on it, resulting in a relatively uneven distribution of the liquid from the Head into the individual upright tubes of the exchanger. The surrender uneven, gravity-based flow of hot liquid through the exchanger tubes reduce the overall cooling efficiency of the device. Until now it was not possible to configure the liquid inlet supply path and head so and structure that the turbulent properties of the inlet flow are effective mainly because of the effort and complexity in the ailordulmg of the utilities and the heads arose that were necessary were to reduce the turbulence in the inlet flow. As a result, they were most equipments share fluid supplies and head structures of a simple, economical design, although at the expense of the Reduction in the efficiency of the device due to the uneven distribution the flowing down liquid took place.

Require systems for vertical, parallel hydraulic siphon flow the supply of a total amount of water that equals or exceeds the total flow, which is related to the final speed of fall of the individual pipe. if this size cannot be achieved with a given system wau> that was water only fed to the tubes that were closest to the inlet, and a "starvation" of the tubes farthest from this inlet occurred. In doing so, however a new pre-distributing and turbulence-calming, perforated impact structure in the head attached to the heat exchanger tubes quite a large amount of water is fed to each of the many tube inlets, whereby the formation of a parallel siphon is ensured even if working with a total flow volume which is less than that at the final velocity related flux for specified dimensioned parallel pipe system.

Inlet flow turbulence is more pronounced in heads to heat exchangers with multiple passages of the type that is being formed, to a siphon effect generate that supports the drawing in of the liquid, or, in the case of the type, that works with a reduced pressure at the inlet. Such a siphon effect is used in order to reduce the power that is necessary, the liquid to the high altitude To lead hot water head.

It is a primary object of the present invention to provide a liquid cooling device, such as a finned tube heat exchanger, which uses a hot liquid collection head which is constructed in an economical manner and equipped with a preferred design seil mag, regardless of availability of small amounts of water, final velocity flow requirements or turbulent Characteristics of the inlet liquid inflow, and which is able to provide a uniform Distribution to effect liquid over the outlet part for flow through to a dai-indivisible Area in heat exchange relationship with an ambient air flow in order to maximize the cooling efficiency of the device to ensure, without the need to use a complicated construction, which would significantly reduce the reliability of the equipment or the manufacturing costs the equipment would increase significantly.

Another object of the invention is to provide a liquid cooling device with a hot liquid collection head in which the liquid all over the head distributed and generally uniformly gathered over the outlet ports of the head is to provide a substantially uniform flow through the mouths and thus a uniform flow through the heat exchanger area to the maximum To deliver cooling effectiveness.

Another object of the invention is to provide an apparatus such as it has been described above, with the distribution of the turbulent inlet flow is achieved via the Ropf by creating a new perforated baffle plate, which serves to divide the head into upper and lower chambers in a way that liquid entering the upper chamber in a turbulent state is predistributed passes through the upper chamber before the liquid passes through the baffle into the lower one Chamber can drain to a generally uniform flow through the outlet mouths of the head, which are located in the lower outlet chambers or. -open tubes.

Another object of the invention is to provide a liquid cooling device of the type described, which has an economical construction by an extremely effective, yet very simple, perforated pre-distribution baffle is created that allows the perforations in the baffle from To be of a similar size to the tube inlets, and in a uniformly aligned manner Patterns to be arranged in order to reduce the manufacturing cost of the head and the To keep the baffle as small as possible, and to provide easier access for cleaning while still providing a uniform flow distribution from the head is achieved even though the liquid flows in the head in the turbulent state to find oneself.

Another object of this invention is to provide a 1 device, as described above, in which the baffle is able to produce a uniform Flow distribution from the head over a wide range of the inlet flow to it in order to increase the applicability of the device by increasing its operability with maximum cooling efficiency under a variety of operating conditions will.

Still another object of the invention is to provide a liquid cooling device of the type described in which the baffle configuration is such that it causes Bring liquid into a relatively still state by adding the liquid is forced through a perforated baffle from an upper turbulent chamber to flow into a lower calm chamber, so that the liquid becomes a uniform Level in the lower chamber collects to further increase the head's ability to Liquid supply to the underlying heat exchange area uniformly to distribute.

Yet another object of this invention is to provide an inclined perforated baffle plate in the head, the one almost constant approach speed at the baffle perforations to generate air from the overlying air chamber to eliminate, as well as an almost constant flow of liquid through the different perforations to achieve a uniform distribution of the liquid in the head chamber below the baffle plate.

In the following, therefore, a liquid cooling apparatus with a multi-tube heat exchanger will be described which has an overhead hot liquid collection and distribution head has to be hot.

Collect fluid and provide a uniform supply to the individual Ensure the tubes of the exchanger. A perforated baffle divides the Head into upper and lower chambers so that parallel siphon action is appropriate can be reached inside the heat exchanger even if the water supply, that is available is unusually low. Likewise, any turSulenter becomes Inward liquid flow into the upper chamber through u&S perforated baffle quenched to ensure a uniform distribution of the liquid in the lower chamber ensure, so that a uniform liquid loading of the heat exchanger area is ensured.

Further advantages and possible applications of the invention result from the accompanying illustration of an exemplary embodiment and from the following Description.

1 is a vertical sectional view of a portion of a multi-tube liquid refrigerator according to the invention, Fig. 2 is a vertical sectional view of a another shape of the head, Fig. 3 is a partially vertical sectional view of a modified one Embodiment of the head shown in Fig. 2 to illustrate a variety of angular arrangements of the baffle plate.

In the figures, a flow distribution and cooling structure 10 is shown, which in a liquid cooling device such as 13.

a liquid cooling tower, is used, this @ üühlturm e.g. may have a dry cooling section and an evaporative cooling section, served by a common source of air movement providing a cooling flow moved by ambient air over both tubing sections. The structure 10 includes one Dry cooling section with a substantially closed, rectangular Ko @ f 14 having a side inlet port .16 that opens into an inner cavity 18 of the head opens.

A fluid supply tube 20 is connected to the cavity 18, in communicating relationship with inlet 16. Head 14 overlies a heat exchanger area 12 and. has a plurality of outlet openings 23 in a bottom wall 22 which allow fluid to flow down from cavity 18 into area 12; A plurality of finned outlet tubes 24 are in a bottom wall of the head 14 and are connected to the outlet openings 25 in communication.

Tubes 24 extend from bottom wall 22 in parallel in the same way Distance from one another into area 12 downwardly by a path of liquid flow Deiinieren in indirect heat exchange with the ambient air through the area 12. Below the tube 24 is an open top liquid weir box 26 which collects the liquid flowing down from the tubes 24 is dispensed at a level that submerges the lower ends of the tubes. the Liquid in the 1 box 26 runs out of this by being over the something shorter side 28 as it also flows through the mouth 30 in the bottom of the box.

A baffle 32 in the form of a flat plate is on opposite sides Sides and ends are connected to the vertical sidewalls of the head 14 and extend extends transversely substantially entirely across cavity 18 in inclined relationship at an acute angle relative to the flat horizontal bottom wall 22, around the To divide cavity 18 into an upper chamber 36 and a lower chamber 38. The lowest Edge of the baffle 32 is angeorduet adjacent to the inlet 16, which extends into the upper chamber 36 opens while the mouths 23 open into lower chamber 38. The perforated baffle 32 allows a relatively free fluid communication between the upper and the lower chamber and is preferably provided with a Plurality of equally sized ^ perforations 40 arranged in a substantially uniform Patterns are arranged over substantially the entire surface of the baffle 32. A vent 42 on head 14 extending into an upper part of the lower chamber 38 opens, can be connected to a branch with a number of Heads 14 is connected, which are connected in parallel operational relationship and form part of a relatively large heat exchange system.

In operation there is a free, normally turbulent flow of liquid directed through inlet 16 into upper chamber 56. The flat, plate-like configuration of the baffle 32 in Connection with their inclined arrangement, which substantially traverses the cavity 18 causes the turbulent inlet flow extends over the entire upper chamber 36 and only a relatively small one Vapor zone 43 above the liquid level line 44 leaves. The size and arrangement .the perforations 40 are with the area and arrangement of the baffle 32 within of the head 14 is correlated to produce the desired degree of predistribution the turbulent inlet flow across the upper chamber 36 to help.

Fluid flow exists through essentially all of the perforations 40 through by means of the pre-distribution of the liquid in the chamber 36, and therefore liquid collects to a uniform depth within the lower chamber 38, as represented by the liquid level 46 therein, even below changing inflow rates, including lower than normal rates, what otherwise it will lead to a "starvation" of those tubes 24 which are farthest away from inlet 16 mild. This results in a substantially uniform static Liquid pressure just above the bottom wall 22 and a uniform static Pressure at each of the orifices 23, regardless of the water flow rate. Corresponding results in a uniform flow of liquid through the preferably equally large Orifices 23 to the liquid flow uniformly over the area 12 in the subsequent Run down to make the liquid through the tubes 24 leads, although even the Inlet flow to the head is of a turbulent nature, it still creates the baffle 32 a quiet zone in the shape of the lower chamber 38, so that a uniform Distribution of the liquid flow in the underlying heat exchanger region 12 results.

While the tubes 24 the liquid in indirect heat exchange with the ambient air flow in area 12, it becomes clear that the structure 10 adjacent to an evaporative cooling tower can be used, with the liquid from the collection box 26 in direct evaporative heat exchange can be brought with the cooling air flow. In this context he has in detail a particular liquid chiller illustrated and described above Possible application for a combination of wet-dryness in which the liquid after collection within the box 26 from there to an underlying evaporation filler assembly falls in direct heat exchange with another current path from ambient air, this air flow being parallel to the air flow through area 12, whereafter a combination with the outflow of air from the evaporation section before discharge to the atmosphere.

Perforations 40 in the baffle 32 are of a size that is one ensures full distribution of the inflowing liquid over the width of the chamber 56, so that the liquid that collects in chamber 38 in a proportionate.

silent state is held before the liquid passes through the mouths 23 in the bottom wall 22 flows off. The distribution and silence effect on the liquid, occurring in the chamber 36 improves the collection of the liquid in the lower one Chamber at a uniform level above the bottom wall 22.

The entire area of the opening between the upper and lower However, the chamber formed by all faces of the openings 40 constitutes one Fluid flow through the baffle plate 32 safely, with a minimal pressure loss, in order to minimize back pressure resistance compared to the overall pump system keep.

Generally, the perforations 40 are in the perforated baffle 32 of the same size as the size of the tube inlet mouths 27 and preferably they are arranged in a vertical orientation thereto to provide access to the heat exchanger tubes, both in terms of manufacture and maintenance to enable. Alternatively, the baffle 32 is removable, where appropriate. the need the hole orientation or the same hole size between the baffle 32 and the lower plate 22 is omitted. Typically, the diameter of the tubes 24 falls in the range from 1.25 to 5 cm (1/2 to 2 inches).

Therefore, the perforations are usually similar in size and spacing.

The particular arrangement and configuration of the baffle 32 can can be changed as is desirable for a particular head design 14 is held, as well as with reference to the arrangement of the inlet 16. In the in Fig. 1 is the lowermost edge of the baffle plate 32 adjacent to the structure shown Inlet 16 and extends gradually upward therefrom to the im interrupting chamber 38 substantially horizontal flow of inlet flow i. The inlet liquid stream thus effectively strikes the baffle 32 around itself iiuer to expand the chamber 36, but the baffle is inclined so that the Fluid realigned smoothly and into a relatively still state is collected, fObCi turbulence is significantly reduced, adjacent to the upper Surface of the baffle 32, so that the liquid in the lower ram 38 with can flow down with minimal turbulence. The baffle 32 should be at an angle arranged at a substantially constant horizontal speed inside the chamber 36 ensures.

The structure 10 is particularly useful in creating a uniform Current distribution of hot liquid at relatively low Inlet flow rates. This greatly increases the versatility and adaptability the use of the refrigeration device employing a flow distribution structure 10 it is capable of maximum efficiency over a white range of inlet flow rates to work. Even with eyftremeu weather conditions, such as operation in cold weather Weather in which the refrigerator typically operates at reduced flow rates Like, the structure 10 provides a uniform flow distribution in the heat exchanger area 12 in for sure.

FIG. 2 illustrates an embodiment of a head 114 according to FIG Invention adapted for central upward flow of liquid to the distribution head. In this case, the head 114 can again have a rectangular, box-like cross-sectional configuration and it may have a laterally extending trough-like structure or alternatively have a circular, cylindrical structure. A centrally arranged lifting tube 148 extends up through the center of the head 114, nln into a Open upper chamber 136, lower limb from the V-shaped baffle 132 is formed, the lowermost apex of which is in environmental relation to the central elevator 148 is attached. The opposing inclined legs of the baffle 132 extend generally outwardly and upwardly from the top of the lifter 48 to the vertical side walls i34 and are connected to the latter, so that the baffle 132 traverses substantially the entire inner cavity 118, in order to divide them into an upper chamber 136 and a lower chamber 138. Outlet mouths 123 in the bottom wall 122 of the head 114 lead to corresponding finned heat exchanger tubes 124. Vents 142 communicate with the lower chamber 138 in both upper ones Corners of this chamber.

The perforated legs of the baffle 132 are inclined at an angle, by preferably a constant liquid flow rate in opposite Direction from elevator 148, and perforations 140 are of one Size similar to and axially aligned with tubes 124 in FIG an identical pattern, as already described, although, as explained, this one Arrangement and size are not essential for the operation, but the efficiency improved in manufacture and maintenance.

Correspondingly, as in the arrangement of FIG. 1, the liquid collects within the lower chamber 158 to a generally uniform level Generate uniform flow rates through the orifices 123. An alternative arrangement for the inlet tube 116 of the head 114 is indicated by means of dashed lines in Fig. 2 at one location on a vertical sidewall of the head 114. The baffle 132 acts to redistribute the liquid across the chamber 136 and - as a result, a uniform flow of liquid through the mouths 123, when liquid is supplied through inlet 116.

In this context it should be mentioned that the embodiments of Fig. 1 and 2 are also able to produce a siphon effect, the drawing in The liquid in the upper chamber is made easier by simply closing the vent 42, 142 opposite the atmosphere. The mouths 123 are one size and one Number showing a collection of fluid within the corresponding lower chamber 38 or 138 allowed, up to a height as shown in Fig. 1, preventing the lower chamber from communicating with the the atmosphere is sealed by the outlet ports. With the achievement of such a seal the inner cavity of the head is a continuous flow of liquid through the Create a partial vacuum through the head and trigger the desired siphon effect.

Fig. 3 illustrates in phantom lines another embodiment of the Angle arrangement in which the baffle plate 132 can also be used successfully, although the constant speed arrangement of Figures 1 and 2 is preferred.

Claims (10)

Claims Liquid distribution device for liquid cooling device for intake of the liquid to be cooled and for the uniform distribution of the liquid an underlying area in heat exchange relationship with an ambient air flow, characterized by a head with a liquid collecting internal cavity and an inlet port therein, the head having a plurality of outlet ports having, the one-iler drainage of the liquid from the cavity to the underlying one Area possible; by a baffle inside the head that covers the cavity crosses and divides it into a lower and an upper chamber, the one with the inlet or are in connection with the mouths, the baffle plate over its whole Area is perforated to allow liquid from the upper chamber into the lower chamber to flow, being. constructing the baffle within the Cavity is arranged so that a substantially equal distribution of the liquid is reached via the upper chamber, so that when the liquid flows down into the lower chamber distributes the liquid substantially uniformly across the mouths is distributed regardless of the rate of liquid flow, and is substantially an equal flow of liquid through the mouths is achieved to a complete Ensuring siphon effect therein at different liquid flow rates. 2. Apparatus according to claim 1, characterized in that the mouths of equal size and in a uniform pattern across a bottom wall of the head are arranged, the baffle having a uniform pattern of perforations thereby causing the liquid to be uniform above The upper chamber to be distributed and is generally uniform in the lower chamber when the blood drains through the perforations into the lower chamber collect. 3. Apparatus according to claim i, characterized in that the baffle plate arranged at an angle and provided with a series of perforations of one size which is a substantially constant liquid velocity in both the Chamber above the baffle as well as when the liquid flows through the perforations cause a relatively quiet fluid state adjacent to the To reach mouths. 4. Apparatus according to claim 1, characterized in that the head with a horizontal bottom wall is provided which has the mouths in sih, wherein the baffle consists of a generally flat perforated plate which is located in the cavity at an acute angle relative to the bottom wall. 5. Apparatus according to claim 4, characterized in that the lowest Edge of the baffle is arranged adjacent to the inlet. 6. Apparatus according to claim 5, characterized in that the head is vertical Has side walls, and that the baffle is transversely between the side walls extends substantially completely across the cavity. 7. Apparatus according to claim 6, characterized in that the baffle plate is of a generally V-shaped configuration with the inlet opening above of the baffle essentially in alignment with the apex of this baffle is arranged. 8. Apparatus according to claim 6, characterized in that the head has a includes upright lifter, which is arranged centrally to the side walls and extends up through the lower chamber and opens into the upper chamber, the lowermost edge of the baffle in surrounding the relationship to the lifter is arranged, and wherein the baffle is generally upward and outward extends from the lifter to the side walls of the head. 9. Device according to claim i, characterized in that vertical ribbed Tubes are provided on the head which are in communication with the mouths and extend into the area below to transport liquid, which flows down from the i (opf in indirect heat exchange with the ambient air. 10. Apparatus according to claim 1, characterized in that the baffle plate is provided with a sufficient number of perforations so arranged are that they have liquid near all outlet ports in the bottom wall of the head deliver. L e r s e i t e