Valve design is conservative and simple.  Basic policy evident in hull valve design is to have valves close with pressure.  
          The only valve type of interest from the standpoint of exploitation locally is the high pressure air valve with the lapped collar type stem in lieu of packing.  Reports on this and on other types of valves which have been sent away for analysis will presumably amplify this section when they become available.  
March, 1946


          German valve design has been considered of sufficient interest to become subject of a separate report.  Samples of certain types of valves have been forwarded to Naval Industrial Association for exploitation and report by that agency.  
          This report will deal solely with those aspects of the different types of valves which can be determined by local inspection and by reference to details of piping systems.  
          Discussion will be primarily devoted to special valves and certain standard valves for which specifications are available.  
  Standard Valves  
  1.  These are classified by the Germans under the following heads:  
          A.  Screwed valves (including use with soldered fitting)  
          B.  Flanged valves  
          Under each of these headings appear the following:  
                  I.  Stop valves  
                 II.  Stop-check valves  
                III.  Cocks  
          Under the heading of flanged valves only, the following additional types appear:  
                IV.  ORZ (open-check-close) valves  
                 V.  Gate valves  
          Separate from the foregoing is the following:  
                VI.  Gauge valves (manometer valves)  
  2.  Valves are further classified by material and by service (character of fluid and temperature), and within each classification there is the customary division into types, i.e., through, angle, three-way, etc.  Further, because of differences between gland nuts and stems,  
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  valves with handwheels or cranks are distinguished from those with removable key handles.  
  3.  Pipe fittings are similarly classified.  
  4.  Characteristics of the standard globe valves up to 32mm (1.26") size and 32 kg/sq.cm2 (356 psi) pressure (40 kg - 586 psi for steel valves) are:  
          a.  Minimum use of material  
          b.  Use of multiple materials in assembly to conserve critical types.  
          c.  The conical seat combined with the spherical section disc.  
          d.  Rising spindle, with inside screw, a conical apron to limit travel in the open position, and on stop valves a peripheral groove at the lower end for the double-pin disc retainer.  
          e.  Separate male threaded bonnet with keeper.  
          f.  Female threaded nut and separate packing retainer for valve bonnet stuffing box.  
  5.  Characteristics of globe valves in the group from 40 to 150 mm (1.6" to 5.9") nominal size for pressures up to 10 kg/cm2 (142 psi) and from 160 to 300 mm (6.3" to 11.8") normal size for pressures up to 6 kg/cm2 (85 psi) are as follows:  
          a.  Minimum use of material, with web stiffeners to reinforce strength on through valves.  
          b.  Use of multiple materials to conserve, while using, critical materials.  
          c.  A flat seat, with or without gasket.  
          d.  Rising spindle, with outside screw, a conical apron to limit travel in the open position, and three different arrangements at the lower end of the stem (see e, f, g).  
          e.  On stop valves, a peripheral groove at the lower end, a ring disc retainer with a lock nut and lock washers.  
          f.  On stop check valves, four longitudinal slots at the lower end of the stem, to permit release or admission of fluid for proper functioning of the lift-check feature.  
          g.  On open-check-close (ORZ) valves, a stem with a shoulder at the lower end, and a disc arranged to permit free travel from the closed position to the top of the "check" position, and provide  
    - 2 -


  for lifting the disc by having the shoulder in contact with the disc retainer nut.  
          h.  Bolted bonnet with integral yoke.  
          i.  Gland nut without separate packing retainer.  
          j.  The shape of the end of the valve spindle identifies the general type of valve and material.  
  6.  It is of interest that none of the standard valves described above has a removable valve seat.  On valves for particular services, copper alloy or austenitic steel deposited seats are provided, but in all cases the seat is integral with the valve body.  
  7.  Characteristics of flanged gate valves of types for which specifications are available are:  
          a.  Minimum use of material, with webs to reinforce the body and bonnet.  
          b.  Solid wedge gates.  
          c.  Inside screw on spindle.  
          d.  Non-rising spindle.  
          e.  Open-and-closed indicator operating on a traveling nut principle on the spindle.  
          f.  Spindle gland flange integral with gland, and with two eye bolts.  
  8.  For certain services, brass seatings are provided in the gate valves, which are secured by means of copper alloy solder.  In no case is a removable seat ring provided, and in no case is a split wedge, double disc outside screw or rising spindle employed.  
  9.  The standard gate valves considered include cast bronze, iron and steel and welded steel assemblies.  Size range is from 40 to 1000 mm (1.6" to 39.4") and pressure range is from 142 psi to 14 psi, varying inversely with the size of the valve.  
  10.  Cocks of many types and sizes are employed.  Characteristics of cocks are:  
          a.  Conical plug.  
          b.  All screwed through, drain and tap cocks up to 32 mm (1.26") have external spring loading to maintain surface contact within the cock, and none of these has a stuffing box, although nominal pressures in smaller sizes run as high as 227 psi.  
    - 3 -


          c.  Spring loading on three-way cocks is only carried to the 13 mm (.51" size), which is rated for 142 psi.  
          d.  All through cocks over 1.26" size, and all angle and three-way cocks beyond .51" size, are provided with stuffing boxes with separate glands and gland nuts.  Compression of the packing maintains the surfaces of the cock body and plug in contact.  
          e.  Screw and soldered cocks run as large as 1.26" nominal size.  
          f.  Flanged cocks begin at .78" normal size and run as large as 3.54".  Pressures vary inversely with size, smaller sizes being rated at 142 psi, while the largest size is rated at 43 psi.  
          g.  The end of the stem on all cocks indicates the position of the cock, and whether it is a through, angle, corner or three-way cock.  
  10.  Comparisons of German and U.S. valve weights have been omitted, as the factor of safety on the rating pressure, and direct comparison of material quality, are not available.  Superficially, the valves appear to be lighter size for size, but a comparison of weights for comparable ratings indicates that the German valves are heavier.  In the absence of complete information, the comparison is inconclusive.  
  11.  The special valves on board include the following:  
          a.  Ballast tank vent valves, and flood valves where fitted.  
          b.  Negative tank flood valves.  
          c.  Compartment, air induction and exhaust, and engine air induction valves.  
          d.  Engine exhaust valves.  
          e.  All other hull and back-up valves.  
          f.  All other steel globe valves for services of higher pressure than 40 kg/cm2 (586 psi) and size greater than 32 mm (1.26"), composition globe valves for services of higher pressure than 25 kg/cm2 (356 psi) and size greater then 1.26".  
          g.  All gate valves and cocks for services of higher pressure then the graduated scale of pressures applicable to the valves of these types.  
          h.  All manifolds.  
    - 4 -


  12.  The ballast tank vent valves are of two types:  
          a.  Normal vent valves.  These are outboard opening mushroom valves with gasketed flat seats which are operated either singly or in groups by means of a vertical shaft extending down into the hull, where it is connected through linkage to two single-acting air pistons, one of which raises the shaft and opens the valve, and the other of which lowers the shaft and closes the valve.  A hand lever is also connected to the linkage in order to permit hand operation in the absence of air pressure.  Where groups of valves are operated by a single shaft, the head of the shaft is provided with a yoke which also connects to the valve discs, and lifts all of them simultaneously.  Where only a single valve is operated, however, the shaft extends down through the hull from the center of the disc.  The size of the air cylinders and shafts is dependent upon the size and the number of individual mushrooms operated simultaneously.  One of each pair of air cylinders is equipped with an apron in which there is a hole.  A pin can be inserted through the operating gear housing and through the hole in the apron to secure the valve in a closed position.  The linkage is of such character as to introduce an appreciable bending moment on the valve operating shaft when the valve is opened, and is on dead center only when the valve is closed.  
          b.  Emergency vent valves.  These are hinged flapper type valves with gasketed flat seats which close the tank end of the vent ducts.  They are inboard opening, and are operated from within the vessel by means of linkage and a threaded spindle turned by a handwheel.  The size corresponds to the size of the vent ducts.  
  13.  In addition to the foregoing, gate valves are installed in the vent lines of fuel ballast tanks.  These are standard gate valves with steel body, bronze spindle and permanent bronze wedge bearing surface.  
  14.  The ballast tank flood valves are counterweighted rectangular hinged valves in the bottom of fuel ballast tanks and of one main ballast tank.  The open inboard.  One or more valves are installed, depending on the size of the tank and the flooding area desired.  Where two or  
    - 5 -


  more valves are installed in one tank, the linkage connections are made in parallel to a common traveling nut and worm in the tank.  The worm mechanism is connected by means of shafting and bevel gears to a crank within the vessel.  Hand operation of the crank opens or closes all flood valves on the one side of the tank.  The valves are steel, with oil-resistant rubber gaskets.  The operating gear is part steel, but chrome steel and bronze are used for rotating and bearing parts.  
  15.  The negative tank flood valve is a mushroom valve opening outboard.  The valve disc is provided with a screw thread, and is raised or lowered by rotating the valve spindle which is threaded into the stem portion of the disc casting.  The spindle is fitted with a collar and ball bearings to serve as a carrier for the vent valve disc.  When turning the spindle, guides prevent the disc from turning.  The valve is operated by means of a hand crank from within the vessel.  
          The materials are steel, with chrome steel spindle and disc, bronze carrier and 18/8 screw bushing.  
  16.  The outboard compartment air induction and exhaust and engine air induction valves are mushroom valves with bevel seats and gaskets.  They are operated by handwheels within the vessel, which, via screw threads on the stem, raise or lower the mushroom head as desired.  The inboard end of the stem is also threaded for a traveling nut which indicated whether the valve is open or closed.  The valves are steel, with chrome steel and bronze working parts.  
  17.  The inboard compartment air and diesel intake valves are also rising stem, outboard opening mushroom valves with bevel seats and gaskets, which are operated by means of handwheels on screw threaded stems.  Materials, here too, are steel, with bronze working parts and chrome steel stems.  
  18.  The engine inboard exhaust valve is an outboard opening, counterweighted, hinged flapper valve with a water jacket.  The valve disc is secured to the hinge by means of a pin at the center of the disc, and is further provided with gear teeth on the periphery which engage a worm aligned and concentric with the hinges.  Operation is by means of a handwheel through a screw and forked lever arm to the valve hinge.  The gagging device provided acts to increase the torsional load on the hinge, thereby increasing the  
    - 6 -


  pressure of the valve on the seat.  
  19.  The worm and the gear teeth on the valve disc permit rotation of the disc by means of a ratchet at the end of the worm shaft.  The intention of this is to assist in removal of carbon deposits and provide a tight valve seat.  
  20.  The outboard exhaust valve is an outboard opening, unbalanced, hinged flapper valve with a water jacket.  Like the inboard valve, the center of the disc is secured to the hinge mechanism, and arranged to permit rotation of the disc about the securing pin.  
  21.  Operation is by means of a handwheel operating through a worm, gear segment and linkage to the hinge lever on the valve.  Gagging is accomplished by rigging an extension bar in holes in the rim of the handwheel, taking up as far as possible, and then closing a screw clamp on the operating shaft.  
  22.  Material are steel, but corrosion-resistant material (bronze and monel) are used for rotating and bearing parts.  
  23.  An additional flapper valve is fitted in the exhaust piping outboard, for the purpose of controlling back pressure when using exhaust gases to blow ballast tanks.  This is like the other two exhaust valves arranged to permit rotation of the valve disc.  It is operated within the vessel by a handwheel equipped with a ratchet which retains the wheel, and thereby the disc, in any desired position between "open" and "closed".  
  24.  Other hull and back-up valves are for the most part special.  Of the 101 different valves types and sizes shown in the Hull Closures (Bordwandabaschlüsse) book, only 8 are standard, and none of the eight is a primary valve.  
  25.  There are 42 types or sizes of hull valves opening against sea pressure, and 19 opening inward.  Those opening inward are special service valves or valves with plug closures at the end of the line, e.g., ballast tank flood valves, and sea chest blow lines closing with air pressure.  
  26.  In addition, through cocks are used as the WC overboard discharge valves.  The remaining cocks exposed to sea pressure are confined to grease lines or drain lines.  
  27.  Distribution is as follows:  
    - 7 -


  Hull Back-up
Angle valves opening outboard 33   4
                                 inward 16 (note 1) 17
Mushroom valves opening outward   6 (described above)   -
                                         inward   -   -
Globe valves opening outward   -   2
                                  inward   2 (note 1)   2
Flapper valves opening outward   3 (exhaust)   -
                                    inward   1 (note 2)   -
Gate valves   -   4
Cocks 10 (note 3)   1
  71 30
Note 1. All special service valves or valves backing up screwed plug closures, e.g., fuel oil and compressed air transfer line hull valves, negative flood and inboard vent valves, WRT flood valve, pressure gauge hull valves, sea chest blow valves.
Note 2. Ballast tank flood valves.
Note 3. WC overboard discharge valves, grease cocks, drain cocks.
  28.  The angle and globe valves used in connection with hull openings differ from these for which standards are available.  Generally they are cast or welded body, rising stem (descending stem for outboard-opening valves) valves with outside screw, and with the yoke cast integral with the valve bonnet.  Flat seats are common, but a few bevel seats are found on valves in blow lines.  The only non-rising stem, inside screw valve noted is one hull valve in the fuel oil system which is used for measuring, draining and pressure equalizing purposes in the external normal fuel oil tank.  
  29.  Most of the angle and globe valves on seawater lines have an extra opening in the valve body, which is closed by means of a blank flange.  Inside the valve body, and mounted on the blank flange, is a zinc waster block.  In lieu of this, on certain valves, a pipe plug is fitted, with a zinc cylinder projecting into the valve body from the inner end of the plug.  All valves exposed to exhaust gases are fitted for rotation of the disc on its seat from within the vessel.  The hull valves in the high pressure blow lines are peculiar in that they are spring-loaded, open with air  
    - 8 -


  pressure and closed with sea pressure, operate on a stop-check principle, and are not packed, but rely on a gasket or lap on the valve stem collar for tightness.  
  30.  Materials are steel, with corrosion resisting material for seats, for discs where metallic contact with the seat is called for, and for working threaded parts.  Gaskets, were provided, are either flat with metal retainers, or trapezoidal section cemented into a groove in the valve disc.  
  31.  The gate valves appear to be similar to the standard valves, with solid wedges, inside screws and non-rising stems.  
  32.  Cocks all have lapped conical plugs.  Those for the WC discharge retain pressure between the plug and the valve body by pressure on the valve stem packing.  Those for the voice tube have only a nut on the end of the valve stem to prevent the plug from pulling out.  
  33.  The interior valves which are larger than 1.26" or operate at higher pressures than 568 psi are generally similar in construction to the hull valves in their respective systems.  Valves with interior screws are generally confined to the fresh water, fuel oil, lubricating oil and air systems.  Outside screws are provided on valves in salt water lines.  Flat seats for fluids, and conical seats with spherical discs for gases, are the general rule.  In the case of air valves, replaceable valve seats have been fitted, but other services have seats of the same material as the valve body, or deposited seats of corrosion resisting material.  
  34.  Few gate valves, but many cocks of all sizes, are employed within the vessel.  No special gate valves have been noted, but cocks of all types are provided on air and fluid systems.  Through cocks, angle cocks, three-way, four-way and combination through and four-way cocks are found on the following systems:  
          ballast tank vent valve operating  
          torpedo tube flooding and draining  
          fuel oil transfer and supply  
          circulating water  
          lub oil  
          fresh water  
          voice tube  
  They are used in lieu of other types of quick-acting valves,  
    - 9 -


  and as combination valves permitting simultaneous interlocking operation, for example, putting air pressure on a WRT tank while opening a torpedo tube vent line, or vice versa.  
  35.  All of the cocks are of simple construction, but superior fit.  The smaller sizes maintain contact between plug and body by means of an exterior spring, while the larger sizes depend on packing compression.  
  36.  Manifolds are constructed by assembling individual valves as desired, by welding onto a pipe the fittings necessary to permit use of most of the parts of a standard valve assemblies, or by by casting a common body into which the valves are built.  The last mentioned is the most common, but the pipe with individual valves welded thereon is the only type used on the air systems.  
  37.  Where cast manifold bodies are employed, any desired combination of valves of different types and sizes are combined in the one manifold.  Stop valves, stop-check valves, and open-check-close valves are the three types which are used in combination.  In at least one case, a strainer is also incorporated into the manifold casting.  
  38.  Materials for manifolds correspond to those for individual valves.  Steel is generally used for manifold bodies.  Seats are usually deposited corrosion-resistant material.  Discs are also corrosion resistant, as are also the screw parts and disc lock nuts where provided.  
  1.  Design indicates great efforts to conserve critical material, while giving little consideration to the practicability of replacing worn seats in any other manner than by redepositing additional seat material and remachining the valve or manifold.  
  2.  The use of hull valves opening against pressure is a survival, and in large valves such as the negative tank flood valve necessitates another small valve in parallel with the main valve to admit sea pressure to the inboard side of the valve seat.  
  3.  The high pressure air valve with the gasketed or lapped stem collar in lieu of packing is of interest.  Experience locally is that stems are tight, that the valves are easily operated, and that leakage past the seat presents no problem as long as the valve is not forced down on the seat.  This type of valve is currently being experimented with at the  
    - 10 -


  Naval Shipyard, Portsmouth, and will become subject of a separate report if experiments indicate its adaptability to U.S. submarine practice.  
  4.  The use of easily replaceable zincs is of theoretical interest only, for many of the valves so fitted are located where a docking of the ship would be required in order to permit access for replacement of the zinc wasters.  
  5.  The extensive use of cocks is of interest, in that it provides an intrinsically simple method of reducing the number of valves by combining interrelated functions, and of obtaining quick operation.  At the same time, the construction of the cocks is such that they remain tight only so long as the lap fit is unimpaired.  
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