QUICK CHANGE APPARATUS FOR EFFECTING GAS FLOW PRESSURE REDUCTION WITH LOW NOISE GENERATOR

• US 3,813,079 A
• Filed: 12/10/1971
• Issued: 05/28/1974
• Est. Priority Date: 12/10/1971
• Status: Expired due to Term

• Current Assignee: Dresser Industries Incorporated (Halliburton Company)
• Original Assignee: Gareth Allan Keith, Hans D. Baumann
• Inventors: Baumann, Hans D., Keith, Gareth Allan
• Primary Examiner(s): Klinksiek, Henry T.
• Application Number:
  US05/206,700
• Time in Patent Office: 900 Days
• Field of Search: 138/42 181/46,56 251/127,282,362,210,361 137/269,270,625.37,625.39
• US Class Current: 251/127
• CPC Class Codes: F16K 47/08 for decreasing pressure or noise level and having a throttling member separate from the closure member , e.g. screens, slots, labyrinths
• CPC Class Codes: Y10T 137/5196 Unit orientable in a single location between plural positions
• CPC Class Codes: Y10T 137/86791 Piston
• CPC Class Codes: Y10T 137/86807 Sequential opening or closing of serial ports in single flow line

Abstract

Valve controlling gaseous flow without producing excessive noise. A plurality of multi-perforated, quick change trim cylinders effecting at least two stage pressure reduction. Adjacent of the cylinders having predetermined flow area ratios, and the inner cylinder being invertible to extend, and enclose the valve plug, to either side of the seat.

Claims

1. Apparatus for reducing the pressure of gas flowing in a conduit, and for accomplishing such gas pressure reduction with greatly reduced generation of throttling noise, and comprising, in combination, conduit means defining a gas confining wall;

a gas Flow passage formed within said confining wall;

a transverse partition interiorly dividing said gas flow passage;

an annular port opening through said transverse, passage dividing partition;

a conduit wall opening opposite said partition port opening;

a bonnet removably closing said conduit wall opening;

a valve stem guided through said bonnet for reciprocation coaxially of said partition port opening;

a valve plug mounted coaxially of and for reciprocation with said stem, towards and away from said partition port opening;

means providing a primary pressure reduction stage for the gas flowing through said conduit, comprising an inner or outer cylinder supported between said transverse partition and said removable bonnet and in coaxial relation to said port opening, and a large number of small jet orifices in said inner or outer cylinder, said large number of small jet orifices constituting said inner or outer cylinder as a primary restriction flow area means;

means providing at least one secondary pressure reduction stage for the gas flow through said conduit, comprising at least one complementary, outer or inner cylinder concentric with said primary reduction stage, inner or outer cylinder, and a large number of small jet orifices in said at least one complementary, outer or inner cylinder, said large number of small jet orifices constituting said at least one complementary, outer or inner cylinder as a secondary restriction flow area means;

the number;

cross-sectional-area combination of said jet orifices in said inner or outer, primary pressure reduction stage cylinder, and in said at least one outer or inner, secondary pressure reduction stage cylinder, being that which, for a given gaseous medium at a given or maximum expected flow rate, produces a low pressure drop across the cylinder, and the number;

cross-sectional-area combination of said jet orifices in said inner or outer, primary reduction stage cylinder, and in said at least one outer or inner, secondary pressure reduction stage cylinder, being that which, for a given gaseous medium at a given or maximum expected flow rate, establishes a relatively high vibratory frequency of noise generation by the cylinder, whereby the acoustical efficiency of said gas pressure reducing apparatus is reduced both by increased conduit attenuation and by increased downstream jet shear interaction and turbulent mixing;

the restriction flow area of each succeeding one of said pressure reduction stage cylinders being increased, through greater number and/or size of its jet orifices, relative to the restriction flow area of the next preceding one of said pressure reduction stage cylinders, to such an extent as compensates for the gas density changes resulting from the gas pressure drop across said next preceding one of said pressure reduction stage cylinders;

the restriction flow areas of said primary and secondary restriction flow area means being so relatively proportioned as to effect substantially equal pressure drops across said primary and secondary pressure reduction stages; and

means for further reducing the acoustical efficiency of said gas pressure reduction apparatus by resonant damping, comprising a resonant damping cavity established between each couple of said primary and secondary flow area means cylinders and within said confining wall of said gas conduit, the spacing between said primary and secondary restriction flow area means cylinders, and thereby the volume of said resonant damping cavity between each cylinder couple, calculated for a resonant frequency substantially equal to the sound frequency of the cylinder opening into the cavity.

2. The apparatus of claim 1, wherein the innermost of said primary and secondary restriction flow area means cylinders slidably receives said valve plug, whereby the reciprocation of said stem and plug covers and uncovers the jet orifices of said innermost cylinder and thEreby varies its said restriction flow area.

3. The apparatus of claim 1, wherein, as to any adjacent two of said primary and at least one secondary pressure reduction stage cylinders, the flow area of the second or downstream of said cylinders is twice the flow area of the first or upstream of said cylinders.

4. The apparatus of claim 1, wherein said innermost of said cylinders has a radially inwardly projecting seat for said plug.

5. The apparatus of claim 1, wherein said innermost of said cylinders has a radially outwardly projecting seat for said at least one outer cylinder.

6. The apparatus of claim 1, wherein the jet orifices in said primary pressure reduction stage cylinder comprise helical slots, and wherein the jet orifices in said at least one secondary pressure reduction stage cylinder comprise round holes.

7. The apparatus of claim 1, wherein the jet orifices of at least one of said restriction flow area means cylinders comprise vertical, substantially equidistant columns of helical slots.

8. The apparatus of claim 7, wherein the slots of said vertical columns are gradually reducing in length, in the progression of said columns toward said partition.

9. The apparatus of claim 7 wherein the centerpoints of said helical slots are vertically aligned, whereby said slots are all uniformly distributed circumferentially of said cylinder.