US1783500A - Pressure-reducing valve - Google Patents

Description

Dec. 2, 1930. J. R. EYRE 1,733,500

PRES SURE REDUCING VALVE Filed June 21, 1928 mam 70p Patented Dec. 2, 1930 UNITED STATES,

.r'osEPrI RILEY EY-RE, or HUL NGLAND PRESSURE-REDUCING VALVE Application filed June 21, 1928, Serial No. 287,100, and. in Great Britain November 3, 1927.

The present invention relates to pressure reducing valves. Pressure reducing valves are known in which steam passing from the boiler side of 5 the valve acts on the opposed faces of a lift valve and leaky piston connected together then passes to the inside of the piston and from thence into the out-letor'working side of the valve. Such a type of valve was evolved by the applicant some time ago.

This and other known types of pressure reducing valves present certain difficulties in that, should variation of pressure on the boiler side of the valve take place, a corresponding proportionate variation in pressure on the working side of the valve automatically occurs.

Further, in the known types of pressure reducing valves a detrimental feature exists in that when it is desired to cease operations it is necessary to substantially increase the pressure on the working side of the valve before the lift valve can be closed to cut off the steam passing from the boiler side of the pressure reducing valve to the working side of this.

According to the present invention the lift valve together with its leaky piston connected thereto is partially operated by a spindle eX- tending longitudinally of the valve andpis- 0 ton, this spindle being interrupted for a portion of its length and including a spring or the like resilient element, the remainder of the required opening of the lift valve being effected by a second and independent control. In order to obtain the desired pressure on the working side of the valve the spindle carrying the lift valve and the leaky piston is operated to open this valve until half the desired pressure is obtained, whereupon the independent control isthen operated to bring the pressure on the working side of the valve to the required amount." When closing down of the valve is required, the lift valve has to overcome the accumulative effect of the spring and as a result of this construction, that is, by the adoption of an independent control, the spring of the present invention need only possess a portion of the strength of springs utilized on similar capacity'valves where no independent control is available. As the lift valve only overcomes a considerably reduced accumulative effect of the spring, it is possible to close down the lift valve without causing a rising pressure on the working side of this, with the result that comparatively instantaneous closing of the valve takes place.

In order to overcome the detrimental effects caused by variations in pressure on the boiler side of the valve, the upper face of the piston is greater in area than the lift valve seat. i

In order to obtain this result, and in a preferred form of construction, a separate seat of smaller bore is provided in the top of the housing within which the piston is displaced. By this means, should the boiler pressure increase, this increase in pressure produces a corresponding downward pull on the piston to tend to close the valve a corresponding amount, whereby the pressure on the working side of the valve remains constant.

The housing and the lift Valve and piston are free to expand longitudinally through the main body, casting or housing of the valve proper with the result that the length of the valve and piston and its corresponding seats in the casing remain substantially the same at any temperature. 1 A steam-tight and comparatively frictioniess' packing element is provided at the bottom of the cage to surround the valve spindle. This resilient packingelement is of substan tially'cup shaped form, the base of said element being held between a pair of members on the spindle whilst the walls of the element'are adapted to Contact with the lower walls of the housing and are held against said walls by steam within the housing in order to preventescape of the steam therefrom.

' The invention, is more particularly described with reference to the accompanying drawing which shows in partial cross section, avalve constructed according to the present invention,

In the drawing the valve casing is shown at l with an inlet from the boiler side at 2 the working side through the valve casing 1 and into a cage 6. A valve 7 and leaky piston 8 are mounted on a spindle 9 which passes through the shank portion of the housing t and terminates at an abutment or cap 10. A helical spring 11 is provided between this cap and a further cap 12 mounted on a threaded spindle 13 which lies eo-axial with the spindle 9, this threaded spindle 13 having the usual hand wheel 14, the rotation of which causes the threaded spindle 13 to be longitudinally displaced to cause compression in the spring 11 and to lift the spindle 9 together with the leaky piston 8 and valve 7.

A removable seat 15 is threaded or otherwise mounted on the upper portion of the housing l to act as a sad for the valve 7. will be noticed that the internal eiameter of this seat is less than the internal diameter of the housing t and the external diameter of the leaky piston 8, and in consequence of this, when the valve 7 is in an elevated position away from its seat, should the boiler pressure increase, the effect of this will be to force the floating valve in a downward direction by reason of the fact that the area on the upper portion of the leaky piston 8 is greater than the cross sectional area of the valve seat The housing a is provided with an inlet orifce 16 and orifices 17 whilst the casing 1 is provided with an orifice 18 to allow for steam to pass from the boiler side of the valve through the orifice 16 past the periphery of the leaky piston 8, through the orifices 17 and through the orifice 18 in the casing 1 into a chamber 19, in which, an auxiliary valve 20 is provided which is operated by a hand wheel 21 for opening and closing the valve, the steam being allowed to pass through this valve into the working side 3 of the reducer valve when the valve 20 is opened.

The usual stop 22 is provided at the top of the casing 1 to prevent excessive lift of the valve 7.

It will be noticed from the drawings that the housing 4: and the spindle 9 with its valve 7 and leaky piston S are both free to expand according to the temperature of the steam passin through the valve and in consequence of this no relative expansion between the housing 4 and th leaky piston 8 takes place.

A shoulder as shown at 24: is formed on the valve spindle 9 considerably below the leaky piston S. An annular member 25 of semii'aircular longitudinal section is adapted to be placed over the spindle and abut against the shoulder 24c whilst a cup shaped packing element 26 is placed over the annular member 25 so that its base is engaged between the arcuate surface of such annular member 25 and a sleeve 27 one end of which is bored out to form a semi-spherical seat for the base of the packing.

The annular member 25, the base of the packing 26 and the sleeve 27 are rigidly held together by means of a lock nut 28, the whole being assembled in the housing or cage (3 which is formed by distance pieces and an end plate 29.

The steam passing down the housing past the leaky piston 8 forces the walls of the cup shaped packing against the inner wall of the housing to form a steam tight joint there by ensuringthat there is no escape of steam from the boiler side 2 of the valve in its passage to the working side 3 of such valve.

The valve works as follows lVhen opening is to be effected, the handle l l is rotated until. half the d .Wred pressure on the working side 3 of the valve is obtained, that to say the valve 7 is opened to half itsv normal extent by this handle 1% against the action of the spring 11. The handle 21 then rotated to open the valve 20 until the desired pressure is obtained on the working 1 side 3 of the reducer valve.

lVhen closing down of the reducer valve is required it will be seen that by reason of the fact that half pressure has been obtained through. the opening of the auxiliary valve l 20, the lift valve 7 has to overcome only the accumulative elfect of the spring 11. with the result that there is no time lag between closing of the cock (not shown) in the working side 3 of the valve and the closing down of the reducer valve itself.

In the constructions which are at present universally adopted, a spring of considerable strength is provided on the spindle of the valve and when closing down is required the valve has to overcome the accumulative effect of this spring with the result that a considerable time lag takes place and high accumulative pressure has to be effected on the working side of the valve before closing; down can take place. i

The spring 11 of the present invention is a light spring at least half the strength of the normal spring used for (.correspondinglv equal capacity known reducer valves. u i

I declare that what ll. claim is:

1. A pressure reducing valve consisting of a lift valve, a leaky piston, a. spindle iiiterrupted over a portion of its length on which said lift valve and leaky piston are mounted, a spring extending over said interrupted portion of said spindle, a lift valve seat, means to displace said lift valve from off its seat, an auxiliary valve and an independent control for said auxiliary valve, the desired pressure on the working side of the reducing valve being obtained by displacement of the lift valve from off its seat until half the desired pressure is obtained, whereupon the auxiliary valve is removed from its seat until the workmg pressure is reached.

2. pressure reducing valve consisting of a casing, a housing within said casing, a division wall between the working side and the boiler side of said casing, a lift valve, :1

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leaky piston rigidly connected to said lift valve, a removable seat for said lift valve on the upper portion of said housing, said removable seat having a smaller internal diameter than the diameter of the leaky piston, and an orifice in said housing connecting the space between said lift valve and the upper portion of said leaky piston with the boiler of said reducing valve, so that on increase in pressure on the boiler side of the valve a greater pressure is obtained on the top of the leaky piston than on the bottom of the lift valve automatically to partiallyclose said lift valve, whereby the pressure on the Working side of the valve remains constant irrespective of pressure fluctuations on the boiler side of the valve.

3. A pressure reducing valve consisting of a casing, a housing within said casing, a division Wall between the working side and the boiler side of the valve, a lift valve mounted within said housing, a leaky piston, a spindle on which said lift valve and said leaky piston are mounted, operating means for the longitudinal displacement of said piston, a cage between one end of said housing and the operating means for the piston, a helical spring between said operating means and said spindle located within said cage, a steam-tight packing between the outer end of said housing and said spindle, and an auxiliary valve having separate operating means for passing fluid to the working side of the valve independently of said lift valve.

4. A pressure reducing valve including a' casing, a division wall across said casing separating the boiler side of the valve from the working side, a housing mounted in said casing, a lift valve within said housing adapted to close said division wall, a leaky piston integral with said valve and moving within said housing and orifices between the working side of the valve and the boiler side of the valve for the passage of steam behind the leaky piston and through the lower portion of the housing, and an auxiliary valve adapted to control the passage of steam from said passages to the Working side of the valve, fluid being passed to the working side of the valve partly through said lift valve and partly through the auxiliary valve.

5. A pressure reducing valve including a casing, a housing mounted in said casing and in a division of said casing separating the boiler side of the valve from the working side, means to open said valve to obtain on the working side of said valve a portion of the pressure existing on the boiler side of said valve, auxiliary means to bring the pressure on the working side of said valve to the desired height and means to prevent leakage of steam in its passage from one side of the valve to the other.

6. A pressure reducing valve consisting of a casing, a housing within said casing, a

dle located within said cage, a shoulder on said spindle, an annular member of semic1 'cularlong1tud1nalsect1on a-buttlng against said shoulder, a sleeve bored out at one end to form a semi-spherical seat and a cup shaped packing, the base of which is adapted to engage between said annular member and said sleeve to'preventescape of steam from the boiler side'of the valve other than to the Working side of said valve.

In witness whereof, I havev hereunto signed my name this 18th day of May, 1928.

JOSEPH RILEY EYRE.

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