US1758295A

US1758295A - Steam-heated apparatus

Info

Publication number: US1758295A
Application number: US385369A
Authority: US
Inventors: Rosenblad Curt
Original assignee: Individual
Current assignee: Individual
Priority date: 1928-08-25
Filing date: 1929-08-12
Publication date: 1930-05-13
Anticipated expiration: 1947-05-13

Description

May 13, 1930. c. ROSENBLAD 1,758,295

STEAM HEATED APPARATUS Filed Aug. 12, 1929 fig. i f1g 5 Patented May 13, 1930 GUBT ROSENBLAD, F SUNDSVALL, SWEDEN STEAM-HEATED APPARATUS Application filed August 12, 1929, Serial No. 385,369, and in Sweden August 25, 1928;

It is well-known to improve the efficiency of the heat transmission surfaces in steamheated apparatus by drawing 01f, together with the condensate, a portion of the steam used for the heating and by returning said steamafter it has been separated from the condensateto the supply pipe to the steamheated apparatus or by utilizing it in other steam consuming apparatus. It has been found that also a little quantity of such steam flowing through will increase the efliciency of the heat transmission surfaces very much.

It is, however, also desired to reduce the temperature of the condensate drawn off as much as possible to obtain the best efficiency possible in the heating process. If the condensate, as stated above, is drawn off together with steam it has a temperature determined by the steam pressure in the outlet tube, i. e. the temperature of saturated steam at said pressure. This temperature is, however, relatively high, and the efliciency of the process is, therefore, reduced to a corresponding extent. Experiments have shown that it is impossible, from an economic point of View, to cool the condensate by increasing the heat transmission surface, because the coefficient of heat transmission for the cooling of the condensate in the last portion of the heat transmission surface is very low, so that a disproportionally large additional surface is required.

The condensate drawn off may certainly be used for pre-heating purposes or for other consumption purposes for which heat of low temperature may be used and thus the'condensate is cooled. This is, for instance, often the case in multiple effect evaporating appa- 40 ratus in which the condensate from the evaporators is used for pre-heating the liquor to be concentrated. It is, however, a wellknown matter of fact that the heat transmission from a medium in the liquid state is sub- 5 stantially lower than that from the same medium, when it is in the gaseous state. The efliciency of the heat transmission surfaces in the pre-heater is, therefore, much lower than that of the surfaces in the apparatus proper.

oil the condensate at a temperature as low as possible. The invention consists, chiefly, in inserting between the sections a throttled passage or other pressure reducing means and after it a steam separator to separate, from the condensate flowing from the preceding section, the steam possibly flowing through as Well as the steam formed from the condensate on account of re-evaporation, said steam being thereafter supplied to the following section.

The throttled passage in combination with the steam separator causes formation of steam from the condensate again on account of re-evaporation and thetemperature of the condensate is'in this way reduced. The steam so formed together with steam flowing through, if such steam is at hand, is in the steam separator freed from the condensate and supplied to the following section in which a lower pressure than that in the preceding section prevails. As the heat transmission from steam is considerably better than that from condensate a considerably higher efficiency in the heating surface of the subsequent apparatus is obtained than would be the casevif the condensate possibly mixed with steam flowing through was directly supplied to the subsequent section.

The condensate from the steam separator may either be drawn off directly by means of a condensate discharger of the usual type or be drawn off in a pipe passing by the following section and be incorporated with the condensate flowing from the latter.

By use of the combination according to the invention the condensate already formed is partially converted to steam on account of re-evaporation and said steam together with excess steam flowing through is utilized in a heat transmission surface at a lower pressure. The heat in the condensate can generally not be utilized in an economic manner as lon as it is absorbed in a liquid but'is according to the invention'caused to be partially absorbed in steam and can, there ore, be utilized more easily. The final temperature of the condensate will, of course, depend upon the conditions of the special case but may generally be said to be about 100 C. Under particular conditions the temperature of the condensate drawn off may bestill more decreased by-use' of vacuum.

The invention may, preferably, be combined with the means for-regulatin the-heat effect in'steam-he'ated apparatus desc ibed in my co-pending U. S. patent application Serial No. 320,694, filed November 20, 1928. In addition to the throttled passage and steam separator provided between thesections of the heat transmissionsurfaces according to the present invention a suitable pumping device is then provided in the steam supply pipe to the section having the lowest pressure. The suction pipe of said pumping device is connected with the outlet pipe from the section having the lowest pressure and to said outlet pipe condensate mixed with steam is supplied from said section-through a throttled passage according to' my said copending U. S. patent application No. 320,694. The condensate from the section or sections having higher pressure may, preferably, be supplied to the same outlet pipe and is then caused first to pass an additional throttled passage and, if desired, also a steam separator, which compensate for the drop-of pressure in the pumping device. In the suction pipe of said pumping. device an air relief cock should also be provided to remove all air present in the s stem.

Some em odiments. of the invention are illustrated in the annexed drawings. Figs. 1 and 2 show a system according to the invention, in which the two sections of the heat transmission surfaces are placed in one and the same outer casing and the steam separator is constructed as condensate discharger or is connected with the outlet pipe from the low pressure section, respectively. Fi 3 shows the same system as that shown in ig. 2 but having three sections in series. Figs.

4 and 5 show a system according to' the in-' vention in combination, at the low pressure section, with the means disclosed in my co- E ending U. S. patent application 320,694. In ig. 4 the sections are enclosed in one and the same outer casing and in Fig. 5 in two separate casings, an additional steam separator being provided in the system shown in said last-mentioned figure.

Referring now to the drawings 1 is a heating apparatus adapted for indirect steam heating by means of the heating element passing through it. Said heating element is, by

means of a throttled passage 2, which may be of fixed area or of adjustable area, divided into a high pressure section 3 and a low pressure section 3", After the throttled passage a combined steam separator and condensate discharger 7 having a float,, valve is provided.

The live steam is supplied through the valve 4 and the condensate from the low pressure section is drawn off through a condensate'discharger 6 having a float valve 5. The direc-' tions of flow are indicated by arrows.

The live steam supplied through the valve 4jfirst .passes the high pressure section 3*, and delivers heat while being partially condensed. The condensate together with the excess steam flowing through passes through the throttled passage 2 to the steam separator 7. Said excess steam serves to remove the.

condensate preciptated onthe walls of the high pressure section 3" and thus to maintain the efliciency of the heat transmission at a high value, because the condensate, which has a poor heat conductivity would otherwise decrease the heat transmission.

. The steam separated in the steam separator 7 which consists of suchsteam flowing through togetl erwith steam formedon ac- .count of are-evaporation from the condensate is then supplied to the low pressure section- 3 and the condensate from the low livers heat to the surrounding liquid in the low pressure section forming still more condensate which has the-same temperature as that of the remaining condensate from the the high pressure section. The condensate flowing from the' two sections has thus one. and the same temperature determined by thepressure prevailing in the low pressure section and said temperature -.is lower than would be the case if the throttled passage and the steam separator had not been provided.

Instead of the combined steam separator and condensate discharger 7 shown in Fig. 1' a steam separator 8 may be provided after the throttled passage 2, 'as shown in Fig. 2, and the condensate therefrom be drawn ofi through a pipe 9 passing by the low pressure section 3" and discharging into the condensatedischarger 6 of the low pressure section.

,In Fig. 3 an embodiment is shown having three pressure stages in the heater. Three therein flows to the intermediate pressure section 3" while the condensate is drawn off through a pipe 11 having a throttled passage 12 to a second steam separator 13 with which the intermediate pressure section 3 also communicates via a throttled passage 2. After the steam and condensate have been separated in said steam separator 13 the steam flows into the low pressure section 3 while the condensate flows through a pipe 14 to the condensate discharger 6 having the float valve 5. From said discharger 6 the condensate formed in the low pressure section 3 is also drawn oft.

In Fig. 4 one embodiment of the invention in combination with means for rcgulat ing the steam flowing through the low pressure section according to my co-pending U. S. patent application No. 320,694 is shown. In an apparatus of the same design as that illustrated in Fig. 2 two throttled passages 15 and 16 are inserted one in the condensate outlet pipe from the low pressure section 3 and one from the steam separator 8 to the condensate diseharger (S. The steam chamber of said last-mentioned discharger is connected with the steam supply pipe 19 to the low pressure section 3 by means of the suction pipe of a pumping device, for instance, an injector 17, which is operated by the steam flowing in the pipe 19 from the steam separator 8 to the low pressure section. In the suction pipe 17 of the injector 17 an air escape cock 18 is inserted to remove the air present in the system.

The steam coming from the steam separator 8 operates the injector l7 and suffers on account thereof a little drop of pressure and flows together with the excess steam sucked by the injector from the outlet of the low pressure section into the inlet of said low pressure section through the pipe 19. The circulation of steam thus brought about renders a high efliciency of the heat transmission also in the low pressure section 3 because the condensate is rapidly removed from the heat transmission surfaces thereof.

Fig. 5 shows a modification of the combination illustrated in Fig. 4. The high pressure section 3 and the low pressure section 3 are here each provided in one

portion

1 and 1 of the heating apparatus and a little steam separator 20 is inserted after the steam separator 8 to separate the steam formed by the re-evaporation caused by the throttled passage 16. Said re-evaporated steam is sucked by the injector 17 which in this case generates a vacuum while the remaining condensate flows to Y the condensate discharger 6 and is pumped off by the pump 21 which may also maintain a vacuum.

In addition to the embodiments illustrated in Figs. 1-5 of the drawings also other embodiments are possible which fall Within the scope of the invention. Any number of cooperating apparatus and any number of sections of'the heating element may be used. If it is desired to reduce the temperature of the condensate discharged from the system below 100 C. the last section is caused to operate in vacuum by substituting a vacuum pump and a condensate pump 21 for the injector and the condensate discharger, respectively.

The throttled passages between the sections of the heating elements may, if the pressures and steam quantities in the plant are constant, be simple throttling discs of constant area, or common steam valves, if it is desired to regulate the pressure to a certain value. If, 011 the contrary, the pressures and steam quantities vary in the system automatic steam pressure reducing valves are, preferably, used, which maintain at constant values the reduced steam pressure and consequently also the temperature of the condensate drawn ott.

lVhat I claim is:

1. In a system comprising steam-heated apparatus having the total heat transmission surface divided into more than one section connected in Series a throttled passage and after it a steam separator in series between all ofthe sections.

2. In a system comprising steam-heated apparatus having the total heat transmission surface divided into more than one section connected in series a throttled passage and after it a steam separator in series between all of the sections, and a condensate pipe connecting each of said'steam separators with the following one. 1

3. In a system comprising steam-heated a pparatus having the total heat transmission surface divided into more than one section connected in series a throttled passage and after it asteam separator in series between all of the sections, a condensate pipe connecting each of said steam separators with the following one, and a condensate pipe connecting the last of said steam separators with the outlet pipe from the'last of said sections.

4. In a system comprising steam-heated apparatus having the total heat transmission surface divided in more than one section connected in series a throttled passage and after it a. steam separator in series between all of the sections, a pumping device, a suction pipe between the outlet pipe from the last of said sections and said pumping device, a throttled passage in said outlet from'the last section before said suction pipe, a pressure pipe between said pumping deviee and the inlet pipe of said last section, and an additional throttled passage in the outlet pipe from the last previous section.

5. In a system comprising steam-heated apparatus having the total heat transmission surface divided into more than one section after it a steam separator 1n serles between tled passage in the condensate outlet connected in series a throttled passage and after it a steam separator in series between. all of the sections, a pumping device, a suction pipe between the outlet pipe from the last of said sections and said pumping device,

a throttled passage in said outlet from the last section before said suction pipe, a pressure pipe between said pumping device and the inlet pipe of said last section, an additional throttled passage in the condensate. outlet pipe from the last previous section,'and a little steam separator immediately after said additional throttled passage. 2

6. In a system comprising steam-heated apparatus having the total heat transmission last section.

vious section, a little. steam separator immediately after said additionalthrottled passage, and means for generating vacuum in said In testimony whereof I have signed my name.

oUR'r ROSENBLAD.

surface divided into more than one section connected in series a throttled passage and after it a steam separator in series between all of the sections, a pumping device, a suction pipe between the outlet pipe from the last sectionand said pumping device, an air escape device in said suction pipe, a throttled passage in said outlet from the last section before said suction pipe, arpressure pipe be; tween said pumping device and the inlet pipe of said last section, and an additional throtconnected in series a throttled passage and after it a steam separator in series between all of the sections, apumping device, a suction pipe between the outlet pipe from the last of said sections and said pumping device, a throttled passage in said outlet from the last section before said suction pipe, a pressure pipe between said-pumping device and the inlet pipe of said last section, an additional throttled passage in the outlet pipe from the last previous section, and means for generating vacuum in said last section.

9. In a system comprising steam-heated apparatus having the total heat transmission surface divided into more than one section connected in series a throttled passage and all of the sections, a pumping device, a suction pipe between the outlet pipe from the I last section and said pumping device, an air escape device in said suction pipe, 2. throttled passage in said outlet from the last section before said suction pipe, a pressure pipe between said pumping device and the inlet pipe of said last section, an additional throttled passage in the outlet pipe from the last pre-