CA1198029A

CA1198029A - Distribution valve

Info

Publication number: CA1198029A
Application number: CA000422657A
Authority: CA
Inventors: Edelbert Tienfenthaler
Original assignee: Gebrueder Sulzer AG
Current assignee: Sulzer AG
Priority date: 1982-03-02
Filing date: 1983-03-01
Publication date: 1985-12-17
Also published as: CH654636A5; DE3271991D1; JPH0341708B2; EP0088146B1; JPS58160673A; EP0088146A1; IN159376B

Abstract

A b s t r a c t The distribution valve comprises an inlet spigot (12) and a first outlet spigot (14). The two spigots (12 and 14) are connected to a distribution chamber (10) and are disposed at right angles to one another. Dia-metrically opposite the outlet spigot (14) a passage spigot (16) leads to a deflection chamber (18). An axially displaceable valve spindle (6) leading out of the deflection chamber (18) via a stuffing box (32) is disposed coaxially of the outlet spigot (14) and the passage spigot (16) and bears a distribution member (7) in the region of the distribution chamber (10). A
second outlet spigot (22) is connected to the deflection chamber (18). Distribution chamber (10) is divided into a circular cylindrical chamber (11) and an annular chamber (13) by a bush (8) mounted in the passage spigot (16) and in the outlet spigot (14). Bush (8) has passage apertures (25) leading from the annular chamber (13) and supports the distribution member (7) radially.
The bush provides a good guidance of the distribution member so that the latter and the relatively long valve spindle cannot be set into vibration.

(Fig. 1).

Description

~ P. 5700 St Gebruder Sulzer Aktienqesellschaft, of Winterthur, Switzerland Distribution valve ~ The present invention relates to a distribution valve comprising at least one inlet spigot disposed on a distribution chc~mber at right angles tO an outlet spigot, a pA~cage spigot connected to the wall of the distribution cha~ber and situated cliametrically c~osite the outlet spigot and leading to a deflection chamber, an axially displ,~ hle valve spindle being provided co~ lly in relation to the outlet spigot and to the passage spigot, said valve spindle le~Alng out of the deflection chamber via a stuffing box and bearing a distribution member in the region of the distribution chamber.
A distrihution valve of this kind is known from German Patent 29 37 873~ One disadvantage of the valve is that the distribution member is secured to a relatively long spindle and therefore tends to vibrate in operation. Such vibration subjects the spindle to fatigue stress and the spindle mounting and the stuffi ~ box may also be deflected~ Sucrh vibration may alco take the fonm of inad~nissible noise.
I~he object of the invention is to obviate these disadvantages simply and cheaply in terms of construction without making the spindle thicker and hence increasing the valve drive forces required.
In accordance with the present invention, the distribution chamber is divided into a circular cylindric chamber ~nd an annular chamber by a bush r~lln~a in the passage spigot and in the o~ltlet spigot, the bush being fol-med with passage apertures leading from the annular chamber. The bush supports the distribution member radially. It has also been found that the flow condition is s~h; 1; ~e~ b~ dividing the medium flow over the various radial p~Cc~ge apertures, the result generally being sm~other opcration of the valve.
According to another feature of the present invention, the distribution member is formecl as a body of revolution bounded on each side by concave quarter-toroidal surfaces of revolution. This gives an additional advantage, the distribution member configuration being more favourable in terms of flow and resulting in a lower pressure loss.

8~

In accordance with a further feature of the present invention, the stuffing box is disposed in a cover of the deflection chamber, said cover closing a cover spigot, the inside diameter of which is large enough for the bush to be introduced, and the bush is secured in the passage spigot and is mounted for axial displacement in the outlet spigot.
These features result in the distribution and vavle maintenance beiny simplified. More particularly, the bush can readily be inspected and replaced if necessary.

In accordance with a still ~urther feature of the present invention, the bush is hardened, at least at an inner circular cylindrical surface, and the distribution member has a hard-metal coating over its periphery, at least to the extent that it touches the bush. This provides better sliding properties and reduces the wear on the sliding surfaces of the distribution member and the bush. Inspection intervals can t:hus be lengthened while in addition there is less pollution of the medium by abraded matter.

In accordance with yet another feature of the present invention, the passage apertures in the bush extend over a greater proportion of the bush periphery towards one en~ of the bush than towards the other end. This enables the adjustment characteristic of the valve or system containing the distribution valve to be made more linear. Controll-ability of the complete system can be improved by suitable choice of the configuration of the width of the passage apertures according to the resistance properties of the branches to which the distribution valve is to be connected.

~ 3 ~

The inventi.on will now be e~plained in detail with reference to the drawing wherein:
Fig. 1 is a longitudinal section through a distribution valve according ~o ~he invention and Fig. 2 is a developed view showing two slots in a modif ied form of the bush shown in Fig. 1, to an enlarged scale in comparison wi th Fig . 1.
The distribution valve 1 in Fig. 1 consists of a housing 2, a cover 4, a valve spindle 6 with a distribution member 7 t and a bush 8. Housing 2 contains a spherical distribution chamber 10 into which there lead, like the arms of the letter T, an inlet spigot 12, an outlet spigot 14, and a passage spigot 160 The lat~er leads from the distribution chamber 10 to a likewise spherical deflection chamber 18 in the housing 2, where spigots are also proviided, again in the directions of the arms of the letter T, namely~ a cover spigot 20 situated diagrammatically opposite the passage 16 and, at a right angle to the common axis of the passage and cover spigots 16 and 20, another outlet spigot 22 which will hereinafter be described as a bypass spigot in order to distinguish it f.rom the outlet spigot 14.
Outlet spigot 14 is disposed coaxially to the passage 16 and the cover spigot 20. Bush 8 extends over the full length of passage spigot 16 and through chamber 10 as far outlet spigot 14. It is mounted with a close fit in the passage spigot 16 and is secured by an annular weld seam 22 to the housing 2 in the region of the end of the passage spigot 16 adjacent the deflection chamber~ The other end of the bush 8 is mounted to be 8~

axially slidable in the outl et spigot 14.
Bush 8 divides chamber 10 into an inner circular cylindrical chamber ll and an outer annular chamker 13 having a cross~section in the form of a segment of a circle. Passage openings 25 extend through the bush and are formed as axial slots with rounded ends.
Webs 26 are left between the slots 25 and are about twice thP width of the slots 25. Bush 8 is suLface-hardened and ground to be circular-cylindrical internally over a length H extending inside the distri bution ch~mber 10. Outside the portion H the bush 8 is turned to a slightly larger diameter.
Cover 4 has a spindle guide 30 coaxial with the cover spigot 20, and a stuffing box 32. Spindle 6 is moved axially by a servomotor (not shown) secured to cover 4. The distribution member 7 at the free end of ~he spindle 6 has a narrow circular cylindrical peripheral surface 36 followed on each side ~y quarter-toroidal surfaces of revolution 37 and 38. Surface of revolution 37 is tangential to the surface of the valve spindle 6 while surface of revolution 38 terminate.s in a point.
The interior of the distribution member 7 has been turned to form a wall of constant thickness. l'he ~ening required for this machining operation is closed by a screw 42, the externally free surface of which forms part of the surface of revolution 38. The cylindrical peripheral surface 36 is formed by the ground surface of a hard-metal coating. The distribution member 7 fits in the bush 8 with medium to large clearance.

As its name su~gests, the distribution valve 1 is used to divide a flow of medium entering housing 2 via inlet spigot 12 into two branch flows which leave the housing via the outlet spigot 14 and the bypass spi~ot 220 The r~lative proportions of the branch flows can be adjusted over a wide range, practically from zero to infinity, by axial displacement of the dis~ribution member 7.
I~e distribution valve 1 does not operate completely symmetrically. If the distribution mem~er 7 is in the bottom position with respect to Fig. l,the flow of medium now leaving the valve completely via the bypass spigot 22 is subjected to grQater throttling, because of the deflection in the deflection chamber, than a flow of medium leaving the housing 2 via the outlet spigot 14 when the distribution member 7 is in the top position. Depending upon the particular function of the valve and the type of plant in which it is to be used, it is therefore advantageously the outlet spigot 14, and not the bypass spigot 22, that is conne~ted to a bypass pipe.
of course the distribution valve ~an be used not only at a distribution point but also wherever the quantities of two combining flows are to be adjusted in relation to one ano~her. It is also possible for the distribution valve to be fed, for example, via spigot 14 and for the branch flows to be withdrawn via inlet spigot 12 and bypass spi~t 22, or to introduce into the distribution valve via the inlet spigot 12 and the bypass spigot 22 two flows of medium ~hich are required to be -- b --3~

combined and then discharge the combined flow via the outlet spigot 14. Such an application may be advantageous in respect of the spigot positions in cases in which disadvantages in respect of the pressuxe drop are probably not important.
Depending upon each application it may be advantageous to fonn the passage apertures 25 in the bush, not as slots with parallel walls but, as shown in Fi~ 2, as slots 25' having a varying width over the length, in which case the wider ends will preferably face the same end of the bush 8 in each case so that the passage apertures 25' extend over a greater proportion of the periphery of ~he bush towards one end ~hereof ~e.g~ ~he bottom end) than towards the other, i~e. the top end, of the bush.
Suchl a construction with club-shaped slots 25' has particular advantages, for example, in the "Triflux"
regulation of steam or vapour generators, in which the temperature of steam or vapour requiring to be inter~
mediately superheated is influenced by supplying a variable quan~ ty of heat thereto by means of a current of high-pressure steam or vapour~ This heat trans~er is effected in at least one double tube, around the outside of which flows flue gas which yields up heat, ste~n or vapour at higher pressure flowing in the inner tube and at lower pressure flowing in the annular chamber between the inner and outer tubes. The heat transfer is influenced by taking a variable proportion of the higher pressure s1eam or vapour through a distribution valve and a bypass line and past the inner tu~e of the Triflux zone.

~ 7~

It has been found in thl5 case that the construction of the bush ~ as shown in Fig. 2 provides considerable advantages in terms of regulation technique, since the relationship between the temperature to be controlled and the val~e stroke can be made linPar or can be improved in respect of linearity.

J

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: .

1. A distribution valve comprising;
a housing having a spherical distribution chamber, a spherical deflection chamber and a passage spigot between and communicating said chambers;
an inlet spigot disposed on a first axis and commun-icating with said distribution chamber;
a first outlet spigot communicating with said distribution chamber on a second axis perpendicular to said first axis and coaxial of said passage spigot;
a second outlet spigot communicating with said deflection chamber;
a bush mounted in said passage spigot and said out-let spigot and dividing said distribution chamber into a circular cylindrical chamber and an annular chamber, said bush having a plurality of apertures therein communicating said cylindrical chamber and said annular chamber with each other;
an axially displaceable valve spindle coaxial of said outlet spigot and said passage spigot; and a distribution member on said spindle within said bush, said bush having a cylindrical length which is greater than the stroke of said spindle, said distribution member increasing in thickness steadily and symmetrically to a plane perpendicular to said second axis, from a thin peripheral edge to a thicker middle section along the circumference of said spindle, whereby said edge is dividing a stream of medium flowing from said inlet spigot to said distribution chamber.

2. A distribution valve as set forth in claim 1 wherein said distribution member is a body of revolution bounded on each side with a concave quarter-toroidal surface of revolution.

3. A distribution valve as set forth in claim 1 further comprising a stuffing box slidably receiving said spindle therein in sealed relation to said deflection chamber.

4. A distribution valve as set forth in claim 3 which further comprises a cover spigot opposite said passage spigot relative to and communicating with said deflection chamber, said cover spigot having an inside diameter greater than an outside diameter of said bush; and a cover on said housing having said stuffing box therein and closing said cover spigot.

5. A distribution valve as set forth in claim wherein said bush is secured to said passage spigot.

6. A distribution valve as set forth in claim 1 wherein said bush has a hardened inner circular cylindrical surface and said distribution member has a hard metal coating at least on a peripheral surface exposed to contact with said bush.

7. A distribution valve as set forth in claim 1 wherein said apertures in said bush extend over a greater peripheral proportion of said bush towards one end than towards an opposite end of said bush.