US1681344A - Condensate-removing system - Google Patents

Description

R. BELL-IRVING ET AL CONDENSATE REMOVING SYSTEM Aug. 21, 1928.

2 Sheets-Sheet Filed Dec. 25, 1926 mus/wens Roam! BsLL-Inv/m Fanc 'n/voueu.

ref N678 Aug. 21, 1928.

R. BELL-IRVING ET AL CONDENSATE REMOVI NG SYSTEM Filed Dec. 23, 1926 2 Sheets-Sheet '2 mm Wm INVf/YTURS Roam B54 (:17? w/vq Fancy Smvoweu.

Arron Ive-Y3 Patented Aug. 21, 1928.

UNITED STATES PATENT OFFICE.

ROBIN BELL-IRVING AND PERCY SANDWELL, 0F POWELL RIVER, BRITISH COLUMBIA,

. CANADA.

CON DENSATE-REMOVING SYSTEM.

Application filed December 23, 1926. Serial No. 156,729.

Our invention relates to improvements in condensate removing systems which are particularly adapted for the removal of condensate from paper dryers, or for-situations where steam is fed to a vessel under pressure from which the condensate or the steam must be'withdrawn. In installations such as paper machines where a number of dryers are heat ed with steam from a supply header and where the condensate which will form in these dryers requires to be removed and conveyed to a hotwell or other receiver, such removal is commonly effected by providing a condensate discharge pipe for each dryer, which pipe enters through the journal of the dryer and terminates close to the bottom of same. In orderthat condensate may flow through this pi e it is therefore necessary to produce an un alanced pressure within the dryer sufficient to lift the water up to the height of the journal and this is commonly effected by maintaining a. difference in pressure between the supply header and the discharge header to which the condensate discharge pipes of r the several dryers are connected. lVith such an arrangement difficulties are experienced by reason of the fact that the bottom of the condensate discharge pipe of one or more of the dryers in the system will become unsealed, under which circumstances steam will flow freely through the condensate discharge pipe and will tend to balance the pressure between the supply header and the discharge header, thus stopping the flowof condensate from the remaining dryers.

Further to the foregoing, unless a considerable diflerential of pressure is maintained between the supply header and the discharge header, the presence of air in the condensate discharge pipe will stop the flow of condensate from the respective dryer to which this pipe is connected. Difficulty is also experienced as a resultof the presence of air in the stea1n as entering the dryer. This air which accumnlates immediately above the surface of the condensate reduces the thermal capacity of the dryer and has not means of egress until such time as the condensate discharge pipe becomes unsealed. In addition to the foregoing it has beenfound desirable to maintain a certain graduation in dryer temperatures from one endof the machine to the other and this is extremely diflicult to accomplish with the differential system as above outlined by reason of the variation in thermal conditions circulation of the steam so collected, and,

with the differential system above described it is also usually necessary to provide high pressure traps or pumps in order to supply sufficient pressure to deliver the condensate to the hot well.

The objects of the present invention are to provide means whereby the above objections may be eliminated and the thermal capacity of each dryer maintained constant which capacity may be regulated so as to permitof any graduation in temperature desired. The invention also provides for the removal of the condensate as it accumulates, without permitting the passage of steam and the discharging of this condensate direct to the hot well, thus eliminating the necessity for using separators, traps, or pumps. Provision is also made for the removal of air from the dryers as soon as it accumulates.

The invention consists essentially of an auxiliary condensate discharge pipe having one end disposed atthe line of high condensate level in the dryer or vessel, a main condensate discharge pipe having its inlet disposed at a level in the dryer or vessel below that of the end of the auxiliary condensate discharge pipe, a valve therefor. and means as condensate is caused toflow through the auxiliary condensate discharge pipe for actuating the valve in order to discharge the surplus condensate from the dryer, as will be more fully described in the following specification, in which be obvious that the system may be applied to any device where pressure is admitted and a liquid accumulated and has to be removed at intervals or to a desired low level.-

The numeral 1 indicates generally a paper machine dryer rotatably mounted and having a hollow shaft 2 at one end which is suitably ill) journalled. The numeral 3 indicates a fitting suitably supported and having a steam tight connection 1 with the end of the shaft 2. The fittin 3 is provided with a steam delivery pipe extending into the dryer 1 which is in communication with asteam header 6. Extending through the steam delivery pipe 5 is a condensate discharge pipe 7, the inner end of which is downwardly curved within the dryer and terminates adjacent to the inner periphery of the dryer at a level as indicated by dotted line 8 lower than the level of the bottom of the auxiliary condensate discharge pipe hereinafter referred to. The outer end of the condensate discharge pipe communicates through the fitting 3 and a pipe 9 to a valve 10 having a balance weight 11 or other suitable closing means secured to one extended portion of its stem 12, tending to close the valve while the opposite extended portion of the stem is adapted to be engaged by a pressurestat control to be hereinafter described. The outlet from the valve 10 communicates with a condensate discharge header 13 which may serve to receive the condensate from other dryers and which is preferably carried through to a suitable hot well and back to the boilers of the plant.

The numeral 14 indicates the auxiliary condensate discharge pipe which extends through the major portion of the discharge pipe 7, passing through its wall at any suitable point as at 15, and extending downwards within the dryer 1 presents its open inner end 16 at the high level line 17 of the condensate. The pipe lel extends outwards through the litting 3 and through a choke coil 18 or any other suitable device for limiting the quantity of steam therethrough. The outer end of the choke coil is connected to a pipe 19 which communicates at one end with a pressurestat 20 provided with a diaphragm 21 having a central button 22 upon which the lower extremity of the valve stem 12 is adapted to rest. Con'mmnicating also with the choke coil 18 is an upstanding leg 23 which is preferably mounted in a vertical chamber 24; having a vent- 25 at its upper extren'iity, and an outlet 26 adjacent its lower extremity which communicates with an auxiliary condensate discharge header 27. While we have shown the vertical leg 23 enclosed within a vertical chamber, it will be obvious that we may adopt any other preferred construction which will prevent syphonic action taking place.

In the modification shown in Figure 2 the condensate discharge valve, indicated by the numeral 28, is of the piston type actuated by a pressure differential and is provided with a stem 29 having a poppet 30 at its lower end which is adapted to open to or close against communication with the condensate discharge header 13. The upper end of the stem 29 is provided with a piston 31 endwise movable in a cylinder open to the valve body 28 and having an outlet 32 from which a pipe 33 extends. The piston 31 is provided with an orifice 34 of lesser sectional area than the pipe 33 and its associated valves.

The numeral 35 indicates a bolt for limiting the upward movement of the piston 31 and the opening movement of the poppet 30. The numeral 36 indicates a pressurestat connected to the outer end of the pipe 1t and having an outlet communicating with an open ended choke coil 37 having a smaller discharge capacity than the pipe. The diaphragm 38 of the pressurestat 36 is connected by a rod 39 with the diaphragm 40 of a further pressurestat 4.1 which is in communication through a pipe 42 with the steam header 6. The outlet pipe 33 leads to a pilot valve 4-3 having a discharge connection 11 and a poppet 45 with a stem 16 projecting downwards through the valve body and bearing adjacent one end upon a suitably fulcrumed arm as at 17, the opposite end of the arm is ope 'ably connected to the rod 39 by a fork 48. The numeral all) indicates a weight slidably mounted upon the arm for the purpose of adjusting the operation of the valve 13.

Having thus described the several parts of our invention we will now briefly explain its function, first having reference to the invention as shown in Figure 1.

Assuming the machine to have been standing with the steam supply shut 011'. On the admission of steam to the dryer 1 condensation will commence and will continue until it reaches the inlet end 16 of the pipe 14. During this accumulation period, steam and such air as may have accumulated in the dryer, will flow through the pipe 14, the choke coil 18 and the leg 23, passing thence to the header 27. When the condensate has reached the high level line 17, condensate is forced through the pipe 14, the choke coil 18 and, accumulating in the leg 23, develops an increase in pressure in the pressurcstat 20 which distorts the diaphragm :21 and opens the condensate discharge valve 10, thus permitting the condensate to discharge directly through the condensate pipe 9 and the valve 10 and into the condensate header 13. As soon as sufiicient condensate has been discharged to again uncover the inlet end 16 of the pipe 14, steam will again llow therethrough and through the choke coil. when it will force the accumulated condensate from the leg :23, thereby reducing the pressure on the pressurestat 20 so that the weight 11 will close the valve 10, thus completing the cycle of operation.

In the modification shown in Figure 2. steam and air will flow through the pipe 14: and the choke coil 3", until the condensate level is raised to the level of the inlet end 16 of the pipe. when condensate will flow therethrough. building up a hydrostatic pressure on the diaphragm 38 of the pressurcstat 36,

luij

menace thus producing an unbalanced condition as between the pipes 14 and 42, and their pressurcstats 36 and 41, which will move the arm 47 toopen the pilot VfllYt-ldii, thus relieving the pressure above the piston 31 of the condensate valve 28, permitting it to be raised by the pressure within thedryer, and the valve to be opened to discharge the condensate therefrom. As the condensate level in the dryer recedes, due to discharge through the valve 28, the pipe 14. is again caused to pass stean'l, which discharges the accumulated water therein through the choke coil 37, so that the pressure between the pipe 14 and the pipe again becomes equalized, allowing the arm d7 to rock back tonormal position, the pilot valve 4-3 to close and pressure to become equalized on both sides of the piston 31, so that it may descend to close the valve 28 against the continued discharge of condensate therethrough.

While we have described our invention as being actuated with one or more devices functioning under the influence of hydrostatic pressure built up by reason of flow of condensate through the auxiliary condensate discharge pipe, it will be obvious that such an increase in pressure could be built up and the system could be caused to function equally well by the introduction of a chamber in lieu of the leg into which the said auxiliary condensate discharge pipe would deliver and from which the steam or condensate so delivered would discharge, the difference in pressure being created by reason of the difference in friction head loss and the presence of flash steam pressure when condensate is flowing as compared with that experienced when steam is flowing. It is also obvious that the system could be caused to function equally well by connecting the said auxiliary discharge pipe to a chamber in which condensate would accumulate at times when condensate was flowing, the weight of the condensate thus accumulated being made to actuate the main discharge valve, or by electrical means wherein the closing of a circuit would be effected by the bridging of a pair of contacts with the condensate flowing through the pipe 1% or by a float operated switch or by the introduction of a device such as a thermostat actuated by the temperature differential of the steam as compared with that of the condensate flowing in the said pipe 14, and that any of the aforementioned or similar arrangements could be employed without departing from the spirit of the invention.

It will also be obvious that this same system may be equally well suited for various other installations, where a gas and a liquid are entered into a closed vessel and from which the liquid is required to be extracted from time to time as it accumulates.

Vhat we claim as our invention is:

1. The combination of a hollow body havmain outlet in response to an initial discharge of condensatethrough said auxiliary outlet.

'2. Apparatus as recited inclaim 1 in which i the normally open auxiliary outlet is arranged to afford an outlet for steam and air contained in said body.

3. The combination of a hollow body having a steam inlet, anormally closed main condensate outlet, a normally open auxiliary condensate outlet through which a restricted prelimiary discharge of condensate is effected when the condensate accumulates in said body to a predetermined level above the main out let and means for opening the main outlet in response to the discharge of condensate through the auxiliary outlet.

4. The combination of a hollow body having a steam inlet and a normally closed main condensate outlet, normally open auxiliary condensate outlet means for ett'ecting a preliminary discharge of condensate when the latter accumulates in said body to a predetce minedlevel above the closed outlet and means utilizing said discharge to effect opening of the outlet.

The combination of a hollow body having a steam inlet and upper and lower condensate outlets, the lower outlet being normally closed and the upper out-let being normally open, means for effecting an initia discharge of condensate through the upper outlet and means for automatically opening the lower outlet in response to a predetermined discharge of condensate through the upper outlet.

6. The combination of a hollow body having a steam inlet, a normally closed main condensate outlet, a normally open auxiliary condensate outlet through which a restricted preliminary discharge of condensate is effected when the condensate accumulates in said body to a. predetermined level and means for periodically opening the main condensate outlet including a device adapted to be actuated by the accumulation therein of a predetermined quantity of condensate supplied through said auxiiiary outlet. 7. The combination with a hollow body having a steam inlet and a normally closed condensate outlet of a. fluid actuated device operable to open said outlet when the condensate accumulates in said body to a predetermined level above the outlet and to subsequently close said outlet before the level of thecondeusate is lowered to the point of unscaling the outlet, said device deriving its motive fluid from the interior of said hollow body through a. normally open conduit com- Inunicating with said body at a point above the aforesaid condensate outlet. 7

8. The combination with a hollow body having a steam inlet and a normally closed condensate outlet, of fluid actuated means for periodically opening and closing said outlet, said fluid actuated means being operatedto open the outlet by condensate delivered thereto from said hollow body through a normally open auxiliary condensate outlet when the condensate accumulates in said body to a predetermined level above the closed condensate outlet and means whereby the condensate outlet is subsequently closed through the agency of said fluid actuated device and before the level of condensate in said hollow body is lowered to the point of unsealing the outlet.

9. In combination a hollow body having a steam inlet, a normally closed main condensate outlet and a normally open auxiliary discharge outlet located above the main outlet, and a fluid actuated device functioning to open the main outlet when the condensate accumulates to the level of the auxiliary outlet and to subsequently close said main outlet before the level of the condensate is lowered to the point of unsealine the main outlet, said fluid actuated device communicating, via the auxiliary outlet, with the interior of said hollow body and deriving its motive fluid therefrom.

Dated at Powell River, B. (1, this 13th day of December, 1926.

ROBIN BELL-IRVING.

PERCY SANDlVELL.

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