US2257805A

US2257805A - Means for regulating the temperature of superheated steam

Info

Publication number: US2257805A
Application number: US178512A
Authority: US
Inventors: Kolling Johann
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1936-07-07
Filing date: 1937-12-07
Publication date: 1941-10-07
Anticipated expiration: 1958-10-07

Description

Oct. 7, 1941. 2,257,805

MEANS FOR REGULATING THE TEMPEAwuRE OF SUPERHEATED STEAM J. KOLLING Fil'ed Dec. '7, 1937 v /IVVf/VTOF Jo/zann Kb/[i279 ATTORNEY I Patented Oct. 7, 1941 MEANS FOR REGULATING? THE TEMPERA- T'URE OF SUPERHEATED STEAM Johann Kiilling, Duisburg, Germany; assignor to The Babcock 8; Wilcox Company, New York,

I Application December 7, 1937, Serial No. 178,512

In Germany July '7, 1936 7' Claims.

This invention relates to means for regulating the temperature of superheated steam of the kind comprising a pump for returning toa boiler drum part of the steam from a superheater.

According to the present invention in means of the. kind specified the steam returned to the drum is cooled approximately to saturated steam temperature before entering the pump. In this way the power required to return the steam to the drum is reduced and the pump is more reliable than if it dealt with the superheated steam.

The invention will now be described by way of example with reference to the accompanying diagrammatic drawing in which: Fig. 1 illustrates an embodiment of the invention wherein desuperheating of the steam or vapor is efiected exteriorly of the boiler drum; Fig. 2 showing a modification wherein desuperheating is effected within the drum; and Fig. 3 indicating a further modification relative to the control of vapor circulation. According to the drawing, steam generated in a steam boiler of any suitable design passes from boiler drum I through superheater 2 to the outlet header 4 and from here to use through pipe 3.

As shown in Fig. 1, a subsidiary flow passes through tube 5 to the spray cooler 8, whereby means of the regulated water spray supplied through pipeline 9 from drum l the superheated steam is reduced to boiler temperature. The steam conveyed by pump 6 leaves the cooler through pipe II and is delivered through pipe 1 into the drum where it mixes with the other saturated steam. If the intention is, however, to use this steam during starting up for heating the water contents of the boiler, it is necessary to pass the steam into the water space in a manner promoting circulation, the valve [2 in pipe 1 being closed and the cooled steam being delivered to the drum through pipe 1' and valve l2.

If it is not desired to use a spray cooler, the steam may be passed through a tubular cooler l3 arranged in the water space of the drum, as shown for example in Fig. 2. Steam is delivered to the cooler from the outlet 4 through pipe l4 having a valve I5 therein, and is discharged through valve id for return to the boiler as in Fig. 1.

The quantity of the steam to be circulated can be altered, if desired, automatically in dependence on the operating steam temperature, by

means of a regulating device ill or by regulating the speed of the pump. Referring to Fig. 1, the

regulating device H] has associated therewith an actuating element l8 of known type which is connected by control pipe l9 to a thermally responsive element 20 at the outlet header 4, thereby providing the desired actuation of device ID in accordance with the temperature of the operating vapor. In Fig.v 3 an arrangement is indicated for controlling the speed of the pump; a suitable speed regulator l8 being associated in known manner with the pump 6 and connected as inthe case of device 10 by control pipe ill to a thermally responsive element 20' at the outlet header 4.

If the capacity of the pump is sufficient, it can be used for effecting cooling of the superheater during starting up, i. e. through the circulation process, as a result of which the usual flooding of the superheater with water can be dispensed with.

It is unnecessary for the saturated steam limit to be closely followed. It is possible to operate with a small superheat or moisture content of the steam. The necessary adjustments are made by means of the regulating valve 9 in the spray pipeline 9 or by a by-pass to the tubular cooler. According to Fig. 2, a part of the superheated vapor from header 4 may be caused to flow through pipe l6 and a part bypassed through the pipe I4 to the cooler l3, the two parts being combined prior to passage through the valve In and pump 6, and the combined quantity having a temperature less than the temperature at header 4 as determined by suitable adjustment of the valves l5 and I1,

What is claimed is:

1. In a system having connected vapor generating and superheating components, the method of regulating the temperature of the outgoing superheated vapor which comprises withdrawing a portion of said superheated vapor, desuperheating said portion, and pumping said portion mechanically in its desuperheated state to return the withdrawn vapor to a point in the path of vapor flow.

2. The combination with a boiler and its connected superheater which includes a desuperheating unit, means for conducting superheated vapor from said superheater to said unit, means for introducing liquid from said boiler into contact with said vapor within said unit, and means including a mechanical pump connected to an outlet from said unit for returning desuperheated vapor from said unit to said boiler.

3. In a system having connected vapor generating and superheating components, the

method of regulating the temperature of the outgoing superheated vapor which comprises withdrawing a portion of said superheated vapor, desuperheating said portion to a predetermined lower temperature irrespective of the initial superheated temperature, subsequently pumping such desuperhe'ated vapor mechanically ior delivering the same under pressure to said vapor generating component, and controlling the supply of desiiperheated vapor available for pumping in accordance with the temperature of the superheated operating vapor.

4. In combination with a vapor supply system eomprisi'ng a boiler and its connected superheater, a desuperheating unit having a connection with said superheater for superheated vapor, means for reducing the temperature of' superheated vapor admitted through said superheater connection, means for delivering such desuperheated vapor to said system for recirculation through said superheater including a mechanical pump connected to an outlet from said unit, means for bypassing superheated vapor around said unit, and means for controlling the heated vapor and being disposed within the liquid space of said boiler for reducing the temperature of superheated vapor admitted through said superheater connection, means for delivering such desuperheated vapor to said boiler including a mechanical pump connected to an outlet from said unit, and means for controlling the temperature of vapor admitted to said pump.

6. In combination with a vapor supply system comprising a boiler and its connected superheater, a desuperheating unit, means for conducting superheated vapor from said superheater to said unit, means for introducing liquid from said boiler into heat exchange relation with said vapor within said unit, means including a mechanical pump connected to an outlet from said unit for returning desuperheated vapor from said unit to said system for recirculation through said superheater, and means for controlling the operation of said pump.

'7. In combination with a boiler and its connected superheater, a desuperheating unit having fluid connections with said superheater and the liquid space of said boiler, said boiler connection including means for spraying boiler liquid into said unit for reducing the superheated vapor admitted through said superheater connection to a substantially saturated state, means for delivering such desuperheated vapor to said boiler including a mechanical pump connected to an outlet from said unit, and means for controlling said pump automatically in response to temperature of the operating vapor.

JOHANN KOLLING.