GB2304300A - Condensate removal device - Google Patents

Abstract

A device for the removal of condensate from steam lines without loss of live steam comprises a solid body having a through passageway with inlet and discharge portions separated by a venturi orifice and end fitments enabling the body to be secured in pipework in a manner whereby the body can readily be removed without disturbance of the pipework and replaced by another like body having a different through passageway configuration. Sight glasses are provided in the end fitments to enable the performance of the device to be observed.

Description

CONDENSATE REMOVAL DEVICE This invention relates to liquid drainage devices for gas conduit systems. In particular, this invention relates to the removal of condensate from steam pipework and the equipment it serves.

Steam lines and the equipment they supply, produce condensate as latent heat is either lost to the surrounding environment or used in the process.

when condensate and steam are both present within steam lines or equipment the condensate gravitates to low points or pockets in the system. Traditionally this condensate is intermittently discharged from these low points into a condensate return system by means of mechanical "Steam Traps" which open in the presence of condensate but close in the presence of steam. Thus the discharge of useful steam into the condensate return is generally avoided. Unfortunately mechanical traps are relatively complex and therefore expensive, having moving parts which may either jam shut, causing the process temperature to drop, or jam open causing steam loss. These traps should therefore be regularly replaced to avoid production problems or energy loss, or monitored to indicate when faulty traps are blowing steam.In either case much money and resources are required which are not always available so in most systems excessive amounts of steam is lost. Consequently in the United States these traps have increasingly been replaced with simple continuous flow fixed orifice traps, as described in US Patents 3,715,895 and 4,171,209. The orifice is positioned so that condensate is forced through a carefully sized small orifice by the steam pressure. Thus while the condensate passes into the condensate system, it obstructs the passage of steam thereby minimising the loss of steam.

The accurate sizing of the orifice, according to condensate load and the pressure differential, is critical to avoid unwanted steam loss. Often and especially with retrofit installations, accurate condensate loads are not available. Also pressure differentials may change during the life of the installation.

US Patents 4,171,209 and 4,745,943 describe a venturi type fixed orifice trap of a unitary durable stainless steel construction each protected from dirt blockage by means of a standard "Y" strainer.

GB Patent 2,088,246 incorporates a filter element within the body but also interchangeable tubular nozzle structures allowing variation of orifice dimensions within a standard body. However, should the condensate load or pressures used for sizing prove to be incorrect, interchanging either the nozzle insert or the whole body of these devices requires the removal of a complete section of pipework. Often the space in which traps are installed is limited so the provision of union fittings for the easy removal of the trap may not be practical. Also the cost or inconvenience of installation of unions means that they are not always fitted.

According to the present invention there is provided a device for drainage of condensate without the passage of live steam, said device having an elongated venturi type orifice within a stainless steel body with fitments on each end to facilitate the interchanging of bodies with differently sized orifices without removal or modification of adjacent pipework.

The invention also provides: - Incorporation of an elongated condensate discharge passageway downstream of the orifice such that its length/diameter ratio is as large as possible but in no instance less than eight to one. Thus this configuration gives optimum performance in the utilisation of condensate to hold back steam when full pressure differential is imposed on the trap and the condensate load is only a fraction of its maximum.

- Optional integral sight glasses, within the fitments on each or either end of the trap body, to enable observation of either backing up of condensate or discharge of live steam into the condensate return.

Thereby under or over sizing of the orifice may be determine during operation and the body readily changed for one with a larger or smaller orifice.

- A circular body construction facilitating its low cost and accurate manufacture from type 304 stainless steel bar on computer controlled lathes due to ease of centering of objects with a circular rather than other shaped cross section. The centre portion of the body is then machined on opposite sides to provide flat seats for assembly with a spanner. This also enables efficient labelling as, by engaging a spanner, the fitter ensures that one of two faces, at right angles to the flat seats, are exposed to view.

Condensate removal devices constructed in accordance with the invention are now described, by way of example only, by reference to the accompanying drawings, in which: Figure 1 shows, in longitudinal section, the arrangement of the device and its adjacent pipework which includes, as a matter of course, a standard "Y" strainer to avoid blockage of the orifice with debris or particulates.

Figure 2 is an end view of the body as seen from the discharge side with the fitment removed.

Figure 3 illustrates the simplicity of the removal and replacement of trap bodies within the typical pipework arrangement.

Figures 4a to 4e show longitudinal sections of bodies with alternative venturi configurations.

Figure 5 shows, in longitudinal section, an alternative arrangement with the body having flanged ends and fitments.

Referring to the drawing of the pipework arrangement shown in Figure 1, under normal operating conditions steam and condensate are present at high pressure within inlet pipe 1. The mixture then passes through the strainer 2 and its filter element 3 so that it is in a clean mixed form within the inlet fitment of the device 4 which is threaded directly into the strainer's outlet 5. The mixture, and the proportion of steam and condensate therein, may be observed by means of one or more integral sight glasses 6 & 7, which, if incorporated within fitment 3, may be positioned on different or opposite sides to facilitate visual inspection. The fitment is secured to the body 8 by means of a threaded collar 9 which engages on the threaded end 10 of the body 8, thereby providing a seal by means of the compression of a fibre washer 11 between flat seats 12 & 13.The mixture of steam and condensate is then presented with a conical constriction 14 formed within the stainless steel body 8, which funnels the mixture towards the orifice itself 15 which has a venturi type of configuration. After passing through the orifice 15 the condensate flashes off steam under lower pressure conditions of the condensate discharge passage 16. As the condensate passes down the discharge passage 16, the flash steam recondenses and then its velocity is gradually reduced as it exists the body 8 through conical discharge 17. The outlet fitment 18 is provided with the same or similar collar arrangement 19 as on the inlet fitment 3 and a threaded coupling 20 may be used for joining to condensate pipe 21. The same or modified, sight glass arrangement 22 may be incorporated within the outlet fitment 18 for observation of the steam content within the condensate.

Referring to Figure 2, the arrangement of opposing flat seats 23, for assembly and disassembly of the trap arrangement by engagement with a spanner, are shown together with the positions 24 for efficient labelling.

Referring now to Figure 3 which shows the device in elevation with the threaded collars 9, unscrewed from the body 8, and then below with the interchangeable body 8 removed. Also illustrated is the arrangement of the labelling position 24 in relation to the flat seats 23, which ensures that one of the two positions 24 are exposed to view when a spanner is engaged on the flat seats 23.

The various possible alternative internal configurations of the body 8 are shown in longitudinal cross section in Figure 4 where the steam/condensate mixture entering the device is depicted by a light arrow and the condensate leaving the device is shown by a dark arrow.

Referring to Figure 4a, an elliptical convex constriction 14a, and discharge 17a are shown which may have varying radii giving increased or decreased curvature compared to that depicted. Figure 4b shows a similar arrangement with, a simplified convex two angled conical constriction 14b, and discharge 17b.

Both the number of angles, their degree and the length of the constriction or discharge may vary. Figure 4c shows an arrangement with another simplified two angled conical constriction 14c, and discharge 17c except that they are both concave rather than convex.

Both the number of angles and the length of the constriction or discharge may again vary. Figure 4d depicts a circular, rather than elliptical, concave constriction 14d, which may alternatively be convex, and a much simplified right-angled discharge 17d.

Another arrangement is shown in Figure 4e where there is no parallel sided discharge passage 16, and instead there is a gradual conical discharge 17e. This is combined with an elliptical concave constriction 14e, but any combination of constriction and discharge is possible.

Referring to Figure 5, showing the alternative flanged arrangement of the device, a flanged strainer 2, is situated upstream of the device. Flange seals 25, are compressed between the flanges of the optional fitment 26, or the body 8, and the strainer 2 or discharge fitment or pipework by means of bolts 27.

Again windows 6, 7 or 22 may be incorporated within the fitments as in Figure 1, and again the body 8, may be readily interchanged by removal of bolts 27. The orifice configurations illustrated in Figures 4a to 4e may also be utilized in the device of Figure 5.

Having described the invention in the foregoing by reference to specific embodiments, it is to be appreciated that the described embodiments are exemplary only and that modifications and variations thereto are possible without departure from the spirit and scope of the present invention as set forth in the appended claims.

Claims (25)

CLAIMS:

1. A device for drainage of liquid/condensate from gas/steam lines and equipment without conveying live gas/steam, said device comprising a solid body with an elongated venturi type fixed orifice and ends enabling the interchanging of bodies with variously sized orifices and corresponding condensate capacities, without removal or modification of adjacent pipework.

2. A device as claimed in claim 1, wherein an elongated discharge passageway downstream of the orifice provides optimum performance in the holding back of gas/steam with the liquid/condensate over varying pressure differentials and liquid/condensate flow rates.

3. A device as claimed in claim 1 or 2, wherein sight glasses, or other means of observing the gas/liquid mixture or condition, are incorporated within the design of the body or fitments, thus facilitating in determining whether the orifice, and its associated liquid/condensate flow capacity, matches the application.

4. A device as claimed in any preceding claim, wherein the body is fabricated from round bar.

5. A device as claimed in claim 4 wherein flats are provided on the body to facilitate removal and replacement.

6. A device as claimed in any preceding claim, wherein the body of the device has flanges which facilitate the seal to adjacent pipework, fittings or fitments with matching flanges.

7. A device as claimed in any of claims 1 to 5, wherein the body of the device is screw threaded at its ends for coupling with complementarily screw threaded unions provided on adjoining pipework, fittings or fitments.

8. A device as claimed in any of the preceding claims, wherein the body of the device is formed of stainless steel.

9. A device as claimed in any of the preceding claims, wherein the orifice of the device has a constricting inlet serving to funnel the liquid/condensate, in use, towards the orifice.

10. A device as claimed in claim 9, wherein the constricting inlet is generally conical.

11. A device as claimed in claim 10, wherein the constricting inlet has portions with different cone angles.

12. A device as claimed in claim 11, wherein the different portions define a generally convex inlet profile.

13. A device as claimed in claim 11, wherein the different portions define a generally concave inlet profile.

14. A device as claimed in claim 9, wherein the constricting inlet has a curved profile.

15. A device as claimed in claim 14, wherein the inlet has an elliptical profile.

16. A device as claimed in claim 14, wherein the inlet has a circular profile.

17. A device as claimed in any preceding claim, wherein the venturi orifice of the device comprises an orifice proper which leads into a larger cross-section discharge passage having a parallel sides portion.

18. A device as claimed in claim 17, wherein the parallel sided portion of the discharge passage opens into an expanding outlet.

19. A device as claimed in claim 18, wherein said expanding outlet has a curved profile.

20. A device as claimed in claim 18, wherein said expanding outlet has a generally conical profile.

21. A device as claimed in claim 20, wherein said conical profile has portions with different cone angles.

22. A device as claimed in claim 21, wherein said portions define a generally convex outlet profile.

23. A device as claimed in claim 21, wherein said portions define a generally concave outlet profile.

24. A device substantially as herein described with reference to Figure 1 or Figure 5 of the accompanying drawings.

25. A device as claimed in claim 24, and wherein the body of the device is modified as shown in any of Figs. 4a to 4e of the accompanying drawings.