US2723109A - Vapor to liquid heat exchanger - Google Patents

Description

Nov. 8, 1955 A. KlRKPATRlcK VAPOR To LIQUID HEAT EXCHANGER 2 Sheets-Sheet l INVENTOR. ALTON KIRKPATRICK d 21W 3 @3 Z mm/ G w H m. am Ma W W E L f /v l a |f d M67/ Z ,aw In HW in l Enr/Ill l -IIMHM I II|| l I I I IIIFLMI.. .n. y m... a ulllll/ .|...I|: I. W 3m /O l I l Inl? 5 www, QNJ l O 9,1/ E r Q A V m Z 7 m w W e .l M n N Nov. 8, 1955 A. KIRKPATRICK VAPOR To LIQUID HEAT EXCHANGER 2 Sheets-Sheer?l 2 Filed Jan. 29, 1955 g@ @O0 OOO@ @@@GQ Q @@@OG O @0090 009090 /f 7 ff@- FIG2.

IN VEN TOR. ALTON KI RKPATRICK BY M1/40M,

atent Oice Patented Nov, 8, 1955 VAPOR TO LIQUID HEAT EXCHANGER Alton Kirkpatrick, Brighton, Mass., assigner to Stone &

Webster Engineering Corporation, Boston, Mass., a corporation of Massachusetts Application January 29, 1953, Serial No. 333,980

4 Claims. (Cl. 257-32) This invention relates to vapor to liquid heat exchangers and especially to vertical tubular vapor to liquid heaters which are adapted to sub-cool the condensate.

Speaking generally, the invention provides adequate sub-cooling with positive and continuous removal of the condensate to another vessel during continuous operation of the heat exchanger. Positive and continuous condensate discharge is attained despite a minimum of pressure differential between the vapor pressure of the heat exchanger and the pressure of the succeeding vessel.

Briey, this is accomplished by employment of a vertical partition member disposed wthin the outer shell of the heat exchanger, the partition being xedly mounted in a fluidtight manner and extending upwardly from the bottom of the outer shell to a point short of the top thereof to divide the outer shell into a condensing chamber and a sub-cooling reservoir. Conventional cooling tubes extend into both chambers and cooling water is circulated therein. A pump feeds collected condensate from the condensing chamber into the sub-cooling chamber and a regulatable outlet is provided through the outer shell from the sub-cooler to discharge the condensate, the capacity of the pump being greater than the vapor condensing capacity of the heater.

Preferably, a sub-partition is vertically disposed within the sub-cooler and is fixedly mounted therein in a fluidtight manner, the sub-partition extending from the bottom to a point short of the top of the sub-cooler to divide the latter into two passes. With this preferred arrangement, the pump is connected to one pass and the outlet leads from the other pass.

More preferably, level control means responsive to changes from a predetermined level of condensate with'- in the condensing chamber is or are provided and suitably connected to the regulatable outlet to maintain the sub-cooler flooded and a desired condensate level in the condensing chamber.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate a preferred embodiment of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings: l

Fig. 1 is a front elevation of a preferred embodiment of the invention, partly in section to reveal the internal structure.

Fig. 2 is a section along the line II-II of Fig. 1.

Fig. 3 is a side elevation of the heat exchanger of Fig. l, partly in section to reveal the internal structure.

Referring now in detail to the illustrative embodiment of the invention shown by way of example in the drawings, a headdown feed water heater is mounted on support legs 1. lt has a vertically disposed outer shell 2 encasing a conventional floating-head type bundle of cooling tubes 3 rising from the fixed tube sheet 3a of partitioned header 3b. Advantageously and as here preferably embodied, the shell 2 is of two-part construction comprising a fixed lower portion or shell collar 2a sealingly attached to the tube sheet 3a, and a removable upper portion 2b bolted to the shell collar. Cooling water supply and circulation Within the tubes is provided by header inlet 4, and header outlet 5, and suitable driving means such as a pump, etc. (not shown).

A tubular partition 6 is vertically disposed within outer shell 2. It is fxedly mounted at its bottom end in sealing engagement (iluidtight manner) with the fixed tube sheet 3a and the inner surface of shell collar 2a. It extends upwardly to a point 6a, short of the top of outer shell 2, thus forming a reservoir for sub-cooling condensate, i. e., a sub-cooler chamber, and, in effect, dividing outer shell 2 into a condensing chamber 7 and a subcooling chamber 8, the latter being open at the top. In the preferred embodiment illustrated, the partition 6 has two plane-surfaced sides at right angles to each other' connected by a third curved side of a contour matching that of the shell. The curved side terminates short of the other two sides and is provided with a radially extending flange 6b which is welded to the fixed shell collar 2a.

A sub-partition 9 is vertically disposed within the subcooler chamber 8 and is fixedly mounted therein in sealing engagement therewith (fiuidtight manner) extending from the bottom to a point 9a short of the top of subcooler 8. Thus, sub-partition 9 divides the sub-cooler into a first pass 10 and second pass 11.

Outer shell 2 has an inlet 12 for vapor leading into condensing chamber 7, and a condensate outlet 13 leads from the second pass 11 to discharge condensate into the next succeeding vessel, e. g., another heat exchanger but of lower pressure. A valve 13a regulates ow through the outlet 13.

A pump 14 is connected by suction chamber unit 15 to the lower portion or condensate collecting portion of the condensing chamber 7, and is" connected by pipe 16 to the lower end of the first pass 10, to remove condensate from the condensing chamber 7 and force it into the subcooling chamber 8 (the first pass 10, as shown). The pump 14 has a greater fluid moving capacity than the steam condensing capacity of the heater.

A float level control 17 responsive to changes in condensate level within the condensing chamber 7 is suitably connected thereto and to the Valve 13a to regulate the valve opening and maintain the condensate level at about the level indicated as 13. Drain plugs 13b and 15a in the shell collar 2a and the suction chamber unit 15 permit of drainage of the sub-cooling chamber 8 and the condensing chamber 7.

Operation of the preferred feed water heater illustrated is as follows: Steam enters the condensing chamber 7 and sub-cooler 8 through the inlet 12 and is condensed on the cooling tubes 3 in each chamber. Condensate collects in the lower portion of sub-cooling chamber S and also of condensing chamber 7 from which latter it is drawn by pump 14 through pipe 15 and forced via pipe16 into the first pass 10 of sub-cooler 8. As the operation continues, more and more condensate is collected in condensing chamber 7 and is forced into the first pass 10 of the sub-cooler by pump 14 until the condensate level therein rises to the top 9a of the partition or weir 9. As the operation continues, condensate spills into the second pass 11l over weir 9 from the first pass and counterows by gravity down the second pass, the condensate level rising rapidly in the second pass, Valve 13a being closed. When both passes are full of condensate, the pump continuing its forcing of condensate into the bottom of the iirst pass, causes the condensate to spill over the top 6a of the baffle 6 and flood into the condensing chamber 7, collecting at the bottom thereof, where it is recirculated by the pump. The condensate level at the bottom of condensing chamber 7 begins to rise considerably at this point of the operation, and when it rises to level 18, float level control 17 actuates valve 13a to open outlet 13 and circulatedsub-cooled condensate discharges from the second pass 11. Float level control 17 opens valve 13a enough to permit removal of condensate at a rate suflicient to maintain` the predetermined level of condensate in condensing chamber 7. As the operationcontinues, entering vapor isv continuously condensed and condensate in the con densing chamber 7 pumped into sub-cooler 8. The subcooler is maintained in a flooding condition so that condensate is rst sub-cooled by passage up the first pass 10 and then spilled into the second'pass 11 for additional sub-cooling, from whence it eventually is discharged to the next succeeding vessel via pipe 13.

With this arrangement, the circulating condensate is substantiallyvsub-cooled prior to discharge to the next succeeding vessel. In addition, a static head of suiiicient pressure is maintained in the second pass of the subcooler at all times so that discharge of the condensate through outlet 13 to the next succeeding heat exchanger o1' vessel can be accomplished continuously and simply at all times, even though the pressure differential between the instant heat exchanger and the one next succeeding be at minimum values.

The capacity of the recirculating pump is in excess of the total condensing capacity of the heater, thus maintaining the sub-cooler section ooded at all times, any surplus overflowing the sub-cooler section to the level controlled condensate storage volume at the bottom of the heater.

Although it is not preferred, the invention may be utilized without the use of sub-partition 9. However, for optimum circulation and sub-cooling, I prefer the form of the invention described. Because of the provision of the two-part shell 2 with a flanged joint between the fixed lower part 2a and the removable upper part 2b at a suitable distance above the lixed tube sheet 3a, the recirculating pump and condensate drain connection can be brought out below this ange and need not be broken in order to remove the heater shell.

In the type of heater described, if the recirculating pump fails, the heater will operate as a conventional heater.

It will be understood that the invention is not limited to the details described and shown in the drawings, except as appears hereafter in the claims.

What is claimed is:

l. A vapor to liquid heat exchanger comprising a vertically disposed shell; a vertical partition member lixedly mounted in fluidtight manner within said shell and extending from the bottom thereof to a point short of the top thereof to divide said shell into a sub-cooling chamber open at the top, and a condensing chamber; cooling tubes within both of said chambers; means for supplying and circulating cooling iiuid through said tubes, an inlet in said shell to supply condensible vapor to said condensing chamber; a pump connected to the said condensing chamber and said sub-cooling chamber to circulate collected condensate from the condensing chamber to said sub-cooling chamber, the capacity of the pump being greater than the total condensing capacity of the heat exchanger; and, an outlet from said sub-cooling charnber to remove condensate.

2. The subject matter of claim 1 including a subpartition member iixedly mounted in uid-tight manner within said sub-cooling chamber and extending from the bottom thereof to a point short of the top thereof to divide it into a first pass and second pass, and characterized by the fact that said condensate outlet leads from one of said passes and the pump is connected to the other of said passes.

3. A vapor to liquid heat exchanger comprising a vertically disposed shell; a vertical partition member iixedly mounted in huid-tight manner within said shell and extending from the bottom thereof to a point short of the top thereof to divide said shell into a sub-cooling chamber open at the top, and a condensing chamber; a sub-partition iixedly mounted in iiuid-tight manner within said sub-cooling chamber and extending from the bottom thereof to a point short of the top thereof to divide sai sub-cooling chamber into a iirst pass and a second pass` cooling tubes within said condensing chamber and sai sub-cooling chamber; means for supplying and circulating cooling fluid through said tubes; an inlet to supply condensible vapor to said condensing chamber; a circulating pump connected between the bottom portions of said condensing chamber and the first pass to circulate collected condensate from the condensing chamber into said irst pass, the capacity of the pump being greater than the total condensing capacity of the heat exchanger; an outlet from said second pass to remove condensate; adjusting means on said outlet to vary the rate of ow therethrough; and, level-controlled means connected to said condenesing chamber responsive to changes in the level of collected condensate in said condensing chamber to regulate said adjusting means to maintain a pre-determined level in said condensing chamber.

4. A vertical tubular heater including a fixed tube sheet and comprising a two-part vertically disposed shell, one of said parts being a ring lixed to the lixed tube sheet of said heater and the other being open at one end and closed at its other end and removably connected at its open end to said ring part; a vertical partition member ixedly mounted in uid-tight manner within said shell to said tube sheet and to said fixed ring part and extending from said tube sheet to a point short of the closed end of said removable shell part to divide said shell into a sub-cooling chamber open at the top, and a condensing chamber; cooling tubes within said chambers; an inlet to supply condensible Vapor to said condensing chamber; pumping means connected to said ring part between said condensing chamber and said sub-cooling chamber for circulating condensate from said condensing chamber to said sub-cooling chamber, the capacity of said pump being greater than the total condensing capacity of the heater, an outlet in said shell ring for removing condensate from said sub-cooling chamber; adjusting means on said outlet for varying the rate of flow therethrough; and, levelcontrolled means connected to said condensing chamber responsive to changes in the level of collected condensate in said condensing chamber to regulate said adjusting means to maintain a predetermined liquid level in said condensing chamber.

References Cited in the iile of this patent UNITED STATES PATENTS

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