Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K1/00—Lift valves or globe valves, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces
  • F16K1/02—Lift valves or globe valves, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces with screw-spindle
  • F16K1/06—Special arrangements for improving the flow, e.g. special shape of passages or casings
  • F16K1/08—Special arrangements for improving the flow, e.g. special shape of passages or casings in which the spindle is perpendicular to the general direction of flow
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K1/00—Lift valves or globe valves, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces
  • F16K1/32—Details
  • F16K1/34—Cutting-off parts, e.g. valve members, seats
  • F16K1/36—Valve members
  • F16K1/38—Valve members of conical shape
  • F16K1/385—Valve members of conical shape contacting in the closed position, over a substantial axial length, a seat surface having the same inclination
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K25/00—Details relating to contact between valve members and seats
  • F16K25/04—Arrangements for preventing erosion, not otherwise provided for
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K47/00—Means in valves for absorbing fluid energy
  • F16K47/04—Means in valves for absorbing fluid energy for decreasing pressure or noise level, the throttle being incorporated in the closure member

Definitions

• the present invention relates generally to an improved design for a throttling valve which prevents deterioration of valve surfaces. Specifically, the present invention is directed to the prevention of erosion and cavitation caused by the sudden vaporization of liquids and following implosion of these vapor bubbles.
• Throttling valves are used in the chemical, petroleum and utility industries for a variety of high pressure drop applications including continuous blow-down sampling, high pressure venting, turbine drain and boiler feed-pump bypass relief .
• the damaging conditions are normally not permanent. They typically occur during transient operation and only a number of times per da or per week.
• Such valves have been utilized as hig and low pressure drain and preheating valves, reheate application, reheater and superheater drain applications, stea turbine, stop and throttle valve drains, and vent application
• Throttling valves have always been subject to rapi deterioration due to erosion, cavitation damage and wire drawing in vital parts.
• Cavitation is the sudden creation an collapse of vapor pockets within a rapidly moving liquid.
• On type of throttling valve which minimizes such deterioratio employes a stellite disk and cylindrical seat coated with a erosion resistant material. Fluid flowing through the annulu between the disc and seat accelerates smoothly until it reache the blunt end of the disk. At this point, the flow are increases at the center of the flow path and the resultan pressure drop at the core of the flow path causes vaporizatio to occur in the cylindrical seat within a layer of continuously flowing unvaporized fluid along the wall of the seat.
• a frequent problem encountered with such throttling valves is that the pressure drop caused within the valve causes vaporization and cavitation of the liquid medium as it passes through the outlet of the valve. Cavitation frequently occurs at locations along the surfaces of the throttling valve and deteriorates those surfaces. Because of the design of the disk and seat, a valve surface exposed to cavitation occurring at the blunt end of the disk must be coated with a wear resistant substance. The cost of coating the surfaces with a wear resistant material can be expensive.
• a further object of the present invention is to provide a throttling valve which requires fewer valve surfaces to be treated with a wear resistant coatings, thereby reducing the cost of valve manufacture.
• It is still another object of the present- invention " t provide a throttling valve which can accommodate cavitating an flashing liquids, liquids containing suspended solids, and tw phase flow.
• a throttling valve which prevents the deterioration of valve surfaces.
• the valve comprises a casing having an inlet conduit for introducing a gas or liquid medium into the valve, an outlet conduit for expelling a gas or liquid out of the casing, and a valve opening for supporting a valve member.
• An annular sealing member is situated within the housing between the inlet and outlet ports.
• the valve further includes a retractable valve member ⁇ lidingly housed within the valve for opening and closing the fluid flow between the inlet and outlet conduits, the valve member having a contoured nose defined by a complex exponential equation which slidingly mates with said sealing means, said nose contour directing the output flow toward the center of said outlet conduit.
• the valve of the present invention has two configurations, a straight line and an angular configuration.
• the straight line configuration incorporates a hard coated protection plate in the outlet section which can be removed.
• Figure 1 is a time lapse section view of the throttlin valve of the preferred embodiment in both the open and close position.
• Figured 2 and 2A are graphs of the profile of the nos section of the valve plug of the preferred embodiment.
• Figure 3 illustrates the exponential formula for the plu of the preferred embodiment.
• Figure 4 is a section view of a second embodiment of th inventio .
• FIG. 1 a cross-section elevated view of a throttling valve 10 in accordance with the present invention is shown in both the open and closed positions.
• the throttling valve 10 of the present invention has a body 12 which is constructed from forged or cast heat resistant carbon steel.
• the valve configuration is of th angle shape design and can be manufactured according to th needs of a specific industry.
• Body 12 has an inlet conduit 13 and a prependicularly disposed outlet conduit 15 fo introducing a liquid medium into and out of the valve.
• Th valve body 12 further includes a bonnet 14 which is agains the pressure seal members by a locking nut 17.
• the bonnet 14 is constructed fro heat resistant low alloyed carbon steel and has a hardene guiding ring 11 at the lower end which provides for vibratio free guidance of the plug.
• the axial portion of the bonnet 14 contains a bore 16 which retains a valve stem 18.
• the spac between the upper part of bore 16 and stem 18 is packed with a packing 20 which is compressed by a hardened gland 22 which i ⁇ moved by the threaded packing nut 21.
• a guide bushing 23 supports the valve stem.
• the bonnet is held in place by th segment ring 27 and the ⁇ upport ring 25.
• Bonnet 14 include ⁇ a cylindrical cavity 24 into which th body of plug 26 extends when raised.
• the inlet conduit 1 extends from a side wall of the body 12 and is connected to source of liquid medium or slurry which enters into the valve.
• valv Various types of substances may be channeled through the valv including mixtures of water and steam or slurries of liquid an abrasive materials.
• the outlet conduit 15 i ⁇ provided at a lower end of th valve housing through which vaporized liquids are discharged
• Outlet conduit 15 is shaped as a conically expanding section
• Conically expanding outlet conduit 15 is protected agains secondary cavitation effects and abrasion by a stellit hardfacing.
• the valve housing includes an annular seal 32 which i situated between the inlet and outlet conduits.
• the sea compri ⁇ e ⁇ an inner annular seat 32 inserted within an oute annular seat 34.
• Annular seats 32, 34 function as a seal whe plug 26 is in a closed position and as a passageway throug which a liquid medium is constantly accelerated in a downstrea direction when the plug is retracted in an open position.
• Th outer annular seat 34 is welded within the body 12 at location adjacent to the outlet conduit.
• Inner annular seat 3 has an inner surface 36 which extends outwardly in an upstre direction from one end and a second inner surface 38 extending outwardly in a downstream direction.
• Gap 40 allows for the thermal expansion of the inner annular seat 32 or distortion of body 12 when an extremely hot liquid medium or gas (500-1000°F) is passed through the valve 10 and over inner annular seat 32. Further, when outer annular seat 34 is welded within the valve body 12, it experiences thermal expansion caused by the extremely high temperatures. Only the inner surfaces 36, 38 are coated with a highly wear resistant substance such as tungsten carbide, chromium carbide or stellite. Durin fabrication, the two seat parts are welded together, machine and then inserted and welded into the body 12.
• valve plug 26 of the preferred embodiment is no described.
• Valve plug 26 directs the flow of a liquid mediu to a specific location downstream of the inner annular seat 32.
• valve plug 26 comprises a generall cylindrical body connected at an upper end to the valve stem 1 with a nose section 42 at its lower end. The valve plug slides up into the bonnet cavity by the valve stem.
• Nose section 42 comprises precisely contoured arcuate walls having a decreasin angle of curvature relative to the central axis of the body 12.
• the contour of the valve nose is defined by the graph shown i Figure 2 and the following equation which is illustrated in Figure 3.
• X stroke, where stroke is equal to the nominal size of th valve.
• Plug 26 directs the flow of liqui medium away from the plug surface in a downstream direction thereby preventing its deterioration.
• Plug 26 may be made of ceramic material, and the contour should be coated with a ver thin and smooth layer of highly wear resistant Tungsten o
• Chromium-Carbide 41 The seat flow path is hard-faced with material such as Stellite 6 or Haynes 25. The resulting liqui flow velocity vector is directed away from the plug contour
• Plug 26 provides linear control characteristics with a ver small dead band 'in the beginning.
• the linear characteristi results in reduced seat sizes and therefore lower gap leakag rates. If the application requires an exponentia characteristic, it can be obtained with a cam in the positione or electronically.
• the throttling valve 10 further includes an outlet condui
• the outlet conduit 15 which expands conically outward and has a greater cross sectional area than the inner annular seat 32. This are provides a location where vaporization and subsequen cavitation can occur.
• the outlet conduit 15 has primary walls 43 which extend outwardly from the inner annular seat 32 in direction towards the outlet conduit 15 and connected to secondary walls 44 which extend parallel to the central axis of the valve housing.
• the walls of outlet conduit 15 are coated with a highly wear resistant sub ⁇ tance similar to that of the first inner surface 32. Because of the difference in cross- sectional areas between the inner annular seat 32 (and surfaces 36, 38) and the outlet conduit 15, a liquid medium travelin over the inner annular seat 32 and into the cavity 1 experiences a large and sudden pressure drop coupled with subsequent decrease in velocity.
• an alternative Y-shaped inlin embodiment of the present invention i ⁇ disclosed.
• the inlet and outlet ports are substantiall parallel and the plug and seat as ⁇ embly extend tran ⁇ eversel to the inlet and outlet conduits.
• the body 12' is con ⁇ tructe of die forged or cast heat resistant low alloyed carbon ⁇ teel
• the bonnet a ⁇ embly 14' i ⁇ identical to that of the firs embodiment.
• This embodiment includes a hard coated ero ⁇ io protection plate 58 in the outlet section- The plate i retained by rings and i ⁇ locked via a bolt 17a.
• the throttling valv of the present invention acts as a control valve for sever services utilizing gas, liquids, mixtures of water and stea and slurries of liquids and abrasive materials under hig pressure and temperature.
• the throttling valve is designed t protect valve surfaces from deterioration caused by erosion a cavitation.
• a liquid medium emerging from a source enters t throttling valve 10 through the source input and conduit po 13.
• the nose portion of the pl 26 is engaged with the inner annular ⁇ eat 32 forming a se which prevents any liquid from passing through the valve 10.
• a conventional activator device forces longitudinal upwa movement of the valve stem 18 towards an open position, there disengaging the plug 26 from the inner annular seat 32 a allowing liquid to flow through the valve 10.
• the plug reced into the cavity of bonnet 14.
• Liquid flowing through the input port 13 i ⁇ direct downwardly over the inner annular seat 32 by the nose of t plug, the contour of the which i ⁇ defined by the followin exponential equation:
• A D/2, where D i ⁇ the diameter of the plug at its tip
• V? C3, where C3 is a value between 0.1 and 2.0
• X ⁇ troke, where ⁇ troke i ⁇ equal to the nominal ⁇ ize of th valve.
• the velocity of the liquid medium i ⁇ greatest whe it reaches the beginning of the second inner surface 38 of th inner annular seat 32.
• the cross-sectional area over th second inner surface 38 suddenly increases as it leads t outlet conduit 15. Because of the sudden change in cross sectional areas between the first and second inner surfaces 36, 38, an abrupt pressure drop occurs, causing vaporization an subsequent cavitation of the liquid medium at or near it saturation point.
• the contoured shape of the nose section 4 direct the liquid flow and resultant cavitation into the cavit 46 downward and away from the surface of the nose 42.
• the bubbles formed as a re ⁇ ult of the cavitation implod within the cavity 46 who ⁇ e wall ⁇ are coated and protects the from being deteriorated.
• the liquid and gas mixture i ⁇ the di ⁇ charged through the output port.
• flanges 54 and 56 may b provided at the inlet conduit 13 and the outlet conduit 15 a seen in Fig. 1, and help connect the throttling valve
• any suitable mountin means can be employed.
• the plug and ⁇ eat assembly operate in a similar manner i the alternative embodiment.
• the abra ⁇ ion resistan attachment plate 58 protects the valve body from the cavitatin liquid.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Lift Valve (AREA)
• Details Of Valves (AREA)
• Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

Family

ID=23440958

Family Applications (1)

Country Status (11)

Cited By (2)

Families Citing this family (8)

Citations (6)

Family Cites Families (3)

• 1990
  • 1990-05-15 CA CA002016800A patent/CA2016800A1/en not_active Abandoned
  • 1990-05-21 JP JP2511263A patent/JPH05502283A/ja active Pending
  • 1990-05-21 BR BR909007442A patent/BR9007442A/pt unknown
  • 1990-05-21 EP EP19900912048 patent/EP0477299A4/en not_active Withdrawn
  • 1990-05-21 WO PCT/US1990/002767 patent/WO1990015944A2/en not_active Application Discontinuation
  • 1990-05-21 HU HU906770A patent/HUT63236A/hu unknown
  • 1990-05-21 AU AU61606/90A patent/AU640678B2/en not_active Expired - Fee Related
  • 1990-06-06 ES ES9001557A patent/ES2025391A6/es not_active Expired - Lifetime
  • 1990-06-14 CN CN90104440A patent/CN1023343C/zh not_active Expired - Fee Related
• 1991
  • 1991-01-31 KR KR1019910700119A patent/KR920701729A/ko not_active Application Discontinuation
  • 1991-12-13 FI FI915872A patent/FI915872A0/fi not_active Application Discontinuation

Patent Citations (6)

Non-Patent Citations (1)

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