WO1984001553A1

WO1984001553A1 - Saddle support

Info

Publication number: WO1984001553A1
Application number: PCT/NO1983/000043
Authority: WO
Inventors: Oddvar Arnt Stebekk
Original assignee: Moss Rosenberg Verft AS
Current assignee: Moss Rosenberg Verft AS
Priority date: 1982-10-11
Filing date: 1983-10-11
Publication date: 1984-04-26
Anticipated expiration: 1986-04-11
Also published as: GB8412068D0; DE3390283T1; GB2136740A; NO823400L; NO151842C; NO151842B; DK285984A; DK285984D0; NL8320309A

Abstract

A prone cylindrical tank or a prone twin tank (1) is supported by a saddle support which comprises a central fixed point (5) that prevents the tank from movement in the transverse direction, and discrete bearing points (6 - 14) on each side of the fixed point. The bearing points have bearing surfaces that are parallel with the longitudinal axis of the tank (1) and are disposed at respective inclinations lying in a plane (15, 17) that passes through said fixed point.

Description

SADDLE SUPPORT The invention relates to a saddle support for a prone cylindrical tank of circular cross section, or a twin tank formed by two prone cylinders of circular cross section, whose axes are parallel with the tank axis, the cylinders intersecting and joining to form an outwardly unified, single tank.

The object of the invention is to enable the tanks to contract/expand without clearances occurring that would result in a redistribution of the cargo contained in the tank.

In accordance with the invention, it is proposed to form the saddle support with a central fixed point, whereby the tank is prevented from movements in the transverse plane, and to provide discrete bearing surfaces on each side of the fixed point. The bearing surfaces are parallel with the longitu¬ dinal axis of the tank, and are disposed at respective inclinations lying in a plane that passes through said fixed point, said respective bearing surfaces cooperating with corresponding bearing surfaces on the tank.

Each saddle support, therefore, has at least three bearing points. For larger tanks, especially, several bearing points or surfaces are provided on each saddle.

A saddle support formed as disclosed in this patent specifi¬ cation permits the object of the invention to be realized, namely, the tank can contract/expand without clearances occurring that would result in a redistribution of the cargo at any of the discrete bearing points. Calculation of stresses and the selection of material thicknesses can there¬ fore be determined with a far greater degree of reliability, which also enables one to construct larger tanks than the conventional tanks in the prior art.

For this type of tank, two saddle supports are normally provided in the longitudinal direction of the tank. The tanks are prevented from longitudinal movement by one of the saddles. This restraint is most simply provided at the fixed point of the saddle in question. Optionally, supplemental limiting means for preventing longitudinal displacement may also be provided at the other bearing points of the saddle.

At the other saddle, as a result, the sliding surfaces must be able to absorb movements that have a component in the tank's longitudinal direction as well as in the transverse direction. The latter component increases with increasing distance from the fixed point. Suitable combinations of materials for the sliding surfaces are selected to provide high surface pressure and low friction, e.g., polished stainless steel against teflon-coated steel or the like. It will be preferable to provide some form of insulation at the bearing points.

Instead of sliding bearing surfaces, it is possible to utilize short rods with cylindrical or spherical bearing surfaces at the ends, or alternatively roller or spherical bearings, depending on whether there is relative movement in one or two directions at the saddle in question. In the former case, the rods can be formed of a material which is a poor conductor of heat, for example, stainless steel.

The tanks are restrained in the vertical direction by suit¬ able means, preferably by cooperating sliding surfaces , see for example Norwegian Patent Application No. 78 3348.

The invention will be discussed in greater detail in the following with reference to the accompanying drawings, wherein:

Figure 1 is a schematic drawing of a ship in cross section, with a saddle-supported twin tank.

Figure 2 shows a cutaway portion of a bearing point, and Figure 3 shows a cutaway portion of a second possible embodi¬ ment of a bearing point.

Figure 1 shows a twin tank 1 constructed of two prone cylinders 2,3 of circular cross section whose axes are parallel with the tank axis, which in this case coincides with the centerline of the ship 4. The cylinders 2,3 inter¬ sect each other, joining' together to form an outwardly unified single tank 1.

Figure 1 illustrates two embodiments of a saddle support, one on the right-hand half of the drawing and the other on the left-hand half of the drawing. In each case, the saddles will be symmetrical mirror images of each other about the longi¬ tudinal central plane of the ship through the σenterline φ . The embodiment shown on the left-hand side of Figure 1 is a saddle support having three bearing points, viz., the central fixed point 5, the bearing point 6, and the corresponding bearing point 7 on the right-hand side.

The embodiment shown on the right-hand side of Figure 1 is a saddle support having a plurality of bearing points 7-14 on each side of the central fixed point 5, which acts as a bearing as well. All bearing points have bearing surfaces that are parallel with the tank's longitudinal axis (vertical on the plane of the paper). , and are disposed at respective inclinations that lie in a plane passing through the fixed point 5. In Figure 1 the planes of inclination for the bearing points 7, 11 and 14 are shown, as indicated by the lines 15, 16 and 17.

On the right-hand side of the drawing, a possible embodiment of the tank's vertical restraining means is shown. Coopera¬ ting sliding surfaces 18 on the tank 1 and ship 4 are arranged on a plane of inclination 19 that passes through the fixed point 5. On the left-hand side of Figure 1 no restraining means is illustrated, but cooperating, sliding

OMPI surfaces like those at 18 could be used. Other known restraining means could also be utilized, as long as they do not hinder the tank's contraction/expansion and movement in the longitudinal direction.

In the above discussion, a saddle support for a twin tank is described, but the principle is equally applicable for cylindrical tanks, in which case the fixed point will be at the bottom of the saddle in the tank's vertical, centerline plane.

The separate bearing points can be made as sliding bearings, but it is also possible to utilize cylindrical or spherical bearing members 20 (roller bearings) , as shown in Figure 2, or short rods 21 with cylindrical or semi-spherical end surfaces, as shown in Figure 3. The disposition of the curved surfaces could also be reversed, i.e., the curved surfaces could be found on the tank and foundation, and the rods would then have straight cut ends. Cooperating surfaces which are both curved (ball race), could also be utilized.

The drawings show only those components that are necessary for understanding the invention. The important point is that the bearings will constantly be under load from the weight of the tank, and acceleration forces, and the tank can contract/expand without clearances arising that would cause redistribution of the cargo at any of the discrete bearing points. Calculation of stresses and the selection of material dimensions can therefore be determined with a far greater degree of reliability.

Claims

Patent Claims

1. A saddle support for a prone cylindrical tank of circular cross section, or a twin tank formed by two prone cylinders of circular cross section whose axes are parallel with the tank axis, said cylinders intersecting and joining to form an outwardly unified single tank, characterized in that the saddle support has a central fixed point whereby the tank is prevented from movements in the transverse plane, and further consists of discrete bearing surfaces on each side of the fixed point, which bearing surfaces are parallel with the longitudinal axis of the tank and have respective inclinations which lie in a plane passing through said fixed point, said bearing surfaces cooperating with corresponding bearing surfaces on the tank.

2. A saddle support according to claim 1, characterized in that the bearing surfaces are sliding surf ces.

3. A saddle support according to claim 1, characterized by roller bearings between the bearing surfaces.

4. A saddle support according to claim 1, characterized by short rods having cylindrical or spherical bearing engage- ment with the bearing surf ces.

\.i-^*U Abstract

A prone cylindrical tank or a prone twin tank (1) is supported by a saddle support which comprises a central fixed point (5) that prevents the tank from movements in the transverse direction, and discrete bearing points (6 - 14) on each side of the fixed point. The bearing points have bearing surfaces that are parallel with the longitudinal axis of the tank (1) and are disposed at respective inclinations lying in a plane (15 , 17)_ that passes through said fixed point.

(Figure 1).