|
|
|
| technical spec • product list • filling • cleaning • maintenance & repair |
 |
||||||
| Frame | Gas
Tanks GA Drawings • Frame The frame is a welded construction of low carbon steel elements BS 4360
Grade 50C and 43C.
TANK
Sun Shield No insulation is provided on this IMO 5 tank, but only a sun shield. This sun shield must under no circumstances be removed as this will result in a vessel with a lower MAWP (Maximum Allowable Working Pressure). The reason for this is the design reference temperatures stipulated by the IMDG Code : ie. 55°C for a vessel with sun shield and 65°C for a vessel without sun shield. The 22 bar design of this vessel for the products (as per product) has been done taking this sun shield into consideration.The sun shield is made of 2 mm thick aluminium sheeting Grade 5251 H6 (Marine Grade). The rivets used are made of 304L stainless steel. GASKET All flanged connections are sealed by using 3 mm thick PTFE gaskets . All threaded connections are sealed by using Loctite 572 PTFE sealer. TORQUE SETTINGS |
|||||
| THE TORQUE SETTINGS
FOR THE VARIOUS FRAME FASTENERS ARE ILLUSTRATED BELOW: Under normal conditions bolts are torqued using a torque wrench. In order to evaluate the correct torque setting the friction resistance of the thread to nut interface needs to be accurately known. In the automotive engine area where parts are cleaned and fairly greasy, this resistance is accurately determinable.Where tank containers have been in marine conditions the re-torquing of bolts should be carried out by the turn of nut method. This method induces an extension of the bolt by applying prescribed rotation of the nut on the bolt. To be effective the head and the nut must have a solid base to react against. The bolt and connection piece are pulled into close contact called a snug tight condition. After suitable marks are made so that the subsequent rotation between the bolt and nut may be observed the nut is subjected to appropriate rotation, depending on the grip length. It is important that the grade of bolt is confirmed to be 10.9 where necessary. |
With regard to the end frame, the four
topmost bolts labelled A in the accompanying sketch are M18 grade 10.9 with
a grip length of 13 mm and should be tightened from a snug tight condition
to a fully tight position by, turning the nut 100° or one-third of a
turn, or two flats. With regard to the M20 grade 10.9 at position C this has a joint thickness of 24 mm and the nut should be turned from a snug tight position to a fully tight position by turning it to 180° or half of a turn. or three flats.With regard to the conical mounts these should be tightened from a snug position by pre-tensioning the rubber by 2.5 mm. The 4 bolts holding the plate to the castellated beam are grade 8.8 and these should be torqued to a nominal 420 Nm with a rotational set of 100°, whichever is the greater. The top bolt on the top centre mount labelled D in the accompanying sketch is an M36 and is fitted onto a rubber bush. The bolt is in shear alone and should only be tightened so that it fits snugly to the washer without unduly squashing the rubber out from underneath it. |
|||||
| Flanges | Manlid | |||||
| All the flanges listed below are manufactured
in SA 350 LF2 material. (a) Manlid and cover (b) Safety relief valve flange (c) Liquid phase flange (d) Gas phase flange (e) Pressure gauge flange (f) Temperature gauge flange (g) Rochester gauge flange. |
The 500 NB manlid is fastened with 20
x M20 studs and nuts. These studs and nuts are manufactured to the following specification: Studs : SA 320 Grade L7 Nuts : SA 194 Grade 4 |
|||||
| Replacement of Manlid Gasket | ||||||
| The repair procedure is
as follows : 1. First ensure that there is no pressure inside the vessel and that the vessel has been properly cleaned or decontaminated. 2. Carefully remove the TIR bars welded between 2 sets of manlid nuts (note: mark the position of these TIR bars in order to refit them correctly). 3. Loosen manhole nuts. 4. Remove manlid cover. 5. Remove all traces of silicone sealer on lid and manlid. Take care not to damage painted surfaces. Also avoid damage to the manlid sealing surface. 6. Place gasket into manlid groove. Do
not use grease to keep the gasket in position. The gasket and sealing
surfaces must be absolutely clean. |
8. Fit manlid cover. 9. Put Loctite thread lock on all the manlid stud threads protruding through the manlid cover. Also put silicone sealant around the bottom of the stud stems to close of the gap between the stud hole and the stud in order to prevent water penetration. 10. Fit the nuts onto the manlid studs and tighten hand tight in cross order sequence. 11. Remove the excess silicone sealant but
make sure the gap between the manlid forging is sealed all round with
silicone. Use a torque wrench and finally tighten the manlid nuts in cross
order sequence to 250 Nm. |
|||||
| Gas Phase Valve Replacement | Liquid Phase Valve Replacement | |||||
| The gas phase manifold assembly consists
of the following components (in sequence from vessel to hose coupling): (a) Fisher C427T-16-10 (2") internal safety excess flow valve screwed into a bolt on flange. (b) Stainless 304 40 NB schedule 80 threaded pipe connection. (c) Fisher 310T-16 (2") globe valve. (d) Threaded pipe connection in stainless 304 pipe 40 NB schedule 80. (e) ACME 1 3/4" connector bolted to the threaded plate connection. Body in stainless steel 304L and cap in cadmium plated carbon steel. |
The liquid phase manifold assembly consists
of the following components (in sequence from vessel to hose coupling): (a) Fisher C427T-16-25 (2") safety internal excess flow valve screwed into a bolt on flange. (b) Threaded pipe connection in 304L 40 NB schedule 80 pipe. (c) Fisher 310T-16 (2") globe valve. (d) Threaded pipe connection in 304L 40
NB schedule 80 pipe. |
|||||
| Safety Relief Valve | Paint | |||||
| This vessel is equipped
with a Mecathermic 140370 (3") or Fort Vale 004/23995 safety relief
valve in stainless steel 304L. A rupture disc is fitted. This relief valve can accept an Elfab Hughes RK80 or Continental Disc or equivalent rupture disc without any modification. A pressure gauge is provided on the relief valve body flange. The relief valve is set to start to discharge at pressure of 22 bar. The relief valve is bolted to the vessel by means of 8 x M24 stainless bolts - each torqued to 185 Nm. Sealing is obtained by means of a PTFE 3 mm gasket.Should the valve be removed, it is essential during replacement that the stainless TIR bar be welded to 2 adjacent safety relief valve bolts in order to satisfy custom's requirements. A new PTFE gasket must be used every time. |
Hempel paint systems are used on both vessel and frame. The specifics of the Hempel system is clearly indicated under technical specification. All repairs and touch-ups must be done with compatible Hempel paints. For the best advice regarding repairs and touch-ups, contact Tankspan Click for Contact information |
|||||
| printing:
for best results use these links to download as PDF |
||||||
 |
|
|
|
|
|
|
