Prestressed hydraulic accumulator

• US 4,603,711 A
• Filed: 10/18/1984
• Issued: 08/05/1986
• Est. Priority Date: 02/27/1980
• Status: Expired due to Fees

• Current Assignee: Hydro Rene Leduc Azerailles
• Original Assignee: Hydro Rene Leduc
• Inventors: Porel, Louis C.
• Primary Examiner(s): Bryant, III, James E.
• Application Number:
  US06/661,663
• Time in Patent Office: 656 Days
• Field of Search: 138/26, 138/30, 29/157 R, 29/446, 92/98 R, 92/128, 285/381, 403/273, 403/300, 220/85 B
• US Class Current: 138/30
• CPC Class Codes: F15B 1/106 characterised by the way housing components are assembled
• CPC Class Codes: F15B 1/12 attached at their periphery flexible separating means in the form of a tube F15B1/16
• CPC Class Codes: F15B 2201/205 using gas
• CPC Class Codes: F15B 2201/3151 the flexible separating means being diaphragms or membranes
• CPC Class Codes: F15B 2201/41 Liquid ports
• CPC Class Codes: F15B 2201/415 Gas ports

Abstract

A hydraulic accumulator comprises two-half shells, the diaphragm therebetween defining two cavities. One cavity contains pressurized gas and the cavity receives hydraulic fluid under pressure. The two-half shells are held together by a mechanical element, such as a belt which has been previously prestressed to a tension selected according to the maximum pressure to which the accumulator will be subjected. The use of the prestressed mechanical element changes the dynamic stresses ordinarily found in a hydraulic accumulator to static stresses, thus minimizing the occurrence of creeks and failure of the device.

Claims

1. An oleopneumatic accumlator comprising:

a first shell having an open end forming a first chamber adapted to receive pressurized gas, and a second shell having an open end forming a second chamber adapted to receive a pressurized hydraulic fluid, a flexible membrane disposed at the open ends of said first and second chamber and forming fluid tight seals therewith;

an elastic metal annular clamping band which is pretensioned along a longitudinal axis prependicular to a diameter of the band by a predetermined amount corresponding to a hydraulic pressure applied to said second chamber at which said first and second shells separate, said band being stretchable primarily in the direction of the pretensioning along said longitudinal axis, said band diameter being oriented parrallel to said open ends;

means for affixing said clamping band to said first and second shells to overlie the edges of said open ends thereof while still retaining at least a portion of said pretension to clamp the shells together; and

whereby said shells separate when hydraulic fluid pressure in excess of said predetermined amount of tension is applied to said second chamber.

2. The accumulator according to claim 1 wherein said elastic metal annular clamping band comprises a cylindrical ring having a shoulder, said ring being previously set under tension along its longitudial axis, which supports itself on one of the shells at said shoulder and is screwed in to the other.

3. The accumulator according to claim 1 wherein said two shells are each provided with a tensioned skirt being screwed one into the other and having a tensioned outer one of said skirts, said tensioned outer skirt being put under tension along its longitudinal axis prior to joining of said shells.

4. The accumulator according to claim 1 wherein said pretension is effected by means of a hydraulic jack disposed coaxially around said elastic metal annular clamping band.

5. The accumulator according to claim 2 wherein said pretension is effected by means of hydrualic jack disposed coaxially around said elastic metal annular clamping band.

6. The accumulator according to claim 3 wherein said pretension is effected by means of hydraulic jack disposed coaxially around said elastic metal annular clamping band.

7. The accumulator according to claim 1 wherein said band is comprised of steel.

8. The accumulator as set forth in claim 1, wherein said elastic metal annular clamping band is formed with at least one opening for permitting the external flow of hydraulic liquid generated by leakage of said hydraulic fluid from between said shells when said shells separate.

9. An oleopneumatic accumulator comprising a first shell having an open end forming a chamber adapted to receive pressurized gas and a second shell having an open end forming a second chamber adapted to receive a pressurized hydrualic fluid, a flexible membrane disposed at the open ends of said first and second chambers and forming fluid tight seals therewith and an elastic metal clamping band stretchable primarily in a direction parrallel to a longitudinal axis perpendicular to a diameter of said band, said diameter being oriented parrallel to said open ends, said accumulator being produced by the process comprising the steps of:

engaging opposite ends of said elastic clamping band to tension said band in said direction along the longitudinal axis perpendicular to a diameter of said band, said tension being in a predetermined amount corresponding to a hydrualic pressure applied to said second chamber at which said first and second shells separate;

affixing said elastic clamping band to said first and second shells to overlie the edges of said open ends; and

disengaging said opposite ends of said affixed clamping band, said affixed clamping band retaining at least a portion of said tension to clamp the shells together, whereby said shells separate when hydraulic fluid pressure in excess of said predetermined amount of tension is applied to said second chamber.

10. The hydraulic accumulator produced in accordance with the process of claim 9 comprising upper and lower half shells separated by a cylindrical wedge and wherein said membrane is clamped between said upper shell and said wedge, whereby said wedge, said membrane and said half shells are pressed against each other by said elastic metal annular clamping band previously subjected to tension.

11. The hydraulic accumulator according to claim 9 wherein said elastic metal annular clamping band comprises an outer belt including a central portion, first and second ends and a shoulder, said first and second ends being seprated from said central portion be said shoulder, said central portion having a crosssection smaller than either of said two ends.

12. The accumulator according to claim 9 wherein said band is formed with at least one opening for permitting the external flow of hydraulic liquid generated by leakage of said hydrualic fluid from between said shells when said shells separate.

13. The accumulator according to claim 9, wherein the prior setting under the tension operation is carried out by a hydrualic jack disposed coaxially around the part which has to be set under tension.

14. The accumulator according to claim 9 wherein said band is comprised of steel.