FR3059310A1 - PRESSURIZED FLUID PRESSURE PRESSURE APPARATUS, MANHOLE HOLE FOR PRESSURIZED FLUID AND METHOD OF MANEUVER - Google Patents

Abstract

Pressure apparatus 10 with a manhole 17 for a fluid comprising an annular flange 16 of a manhole, a lid 1 sealed with the flange 16 in the closed position and screws 18 for fastening the lid 1 to the flange 16 in a larger number to 6 regularly distributed in the vicinity of the outer edge of the cover 1 and the flange 16. In the open position, the cover 1 is articulated to the flange 16 about an axis parallel to said screw 18 and provided with a lever 5 for remote operation said axis, said screws 18 passing through holes 3 formed in the cover, one of the holes 3a having a first diameter, the other holes 3b having a second diameter smaller than the first diameter.

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number: 3,059,310 (to be used only for reproduction orders)

©) National registration number: 16 61514

COURBEVOIE © Int Cl ⁸ : B 65 D 90/10 (2017.01), F 17 C 1/00

A1 PATENT APPLICATION

©) Date of filing: 25.11.16. © Applicant (s): CHARLATTE RESERVOIRS Company (© Priority: by simplified shares - FR. (© Inventor (s): DARDON Fabien. ©) Date of public availability of the request: 01.06.18 Bulletin 18/22. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ® Holder (s): CHARLATTE RESERVOIRS Company by related: simplified actions. ©) Extension request (s): © Agent (s): CABINET NETTER.

MANHOLE PRESSURE APPARATUS FOR PRESSURE FLUID, MANHOLE COVER FOR PRESSURE FLUID AND MANEUVERING METHOD.

FR 3 059 310 - A1

Pressure device 10 with manhole 17 for fluid comprising an annular manhole flange 16, a tight cover 1 with the flange 16 in the closed position and screws 18 for fixing cover 1 to the flange 16 in greater number to 6 regularly distributed in the vicinity of the outer edge of the cover 1 and the flange 16. In the open position, the cover 1 is articulated to the flange 16 about an axis parallel to said screws 18 and provided with a lever 5 for remote operation of said axis, said screws 18 passing through holes 3 made in the cover, one of the holes 3a having a first diameter, the other holes 3b having a second diameter less than the first diameter.

MANHOLE PRESSURE APPARATUS FOR PRESSURE FLUID, MANHOLE COVER FOR PRESSURE FLUID AND MANEUVERING METHOD

The present invention relates to the field of pressure vessels. Such pressure vessels can be a tank fitted to a hydraulic pipe which can be, in particular, a network for the distribution of drinking water or for irrigation, or a network for the disposal of waste water or the transport of chemical liquids; a pressure line, a heat exchanger, a distillation column, etc.

A pressure tank can be hydropneumatic containing a liquid phase and a gaseous phase based on air or a gas for degassing the liquid and operate as a regulation tank, in particular to regulate the pumping pressure and ensure continuity of service. pipeline, in a pressure range between a high level and a low level. A hydropneumatic tank can also be used as an anti-ram tank to compensate for the effects of depression and overpressure caused, for example, by stopping a pump or closing a valve.

In this regard, the documents FR 2 416 417, FR 2 739 766, FR 2 766 883 and FR 2 930 314 are known.

Such pressure vessels must be periodically inspected and maintained. The inspection makes it possible to verify the absence of solid deposit and the absence of corrosion for example. Maintenance can include cleaning, removing a solid deposit, or repairing an anti-corrosion coating. For this purpose, pressure vessels for fluids generally include a large opening called a manhole. Its dimensions are sufficient to let an operator pass. The opening is closed by a cover. The cover and the body of the pressure vessel are sealed when the pressure vessel is used. The cover is fixed to the body of the pressure vessel by regularly distributed screws allowing a force distributed over the body of the pressure vessel. Due to its dimensions, the cover is relatively heavy and must be handled by several operators.

The invention improves the situation.

The Applicant has in fact noticed that the arrangement of pressure vessels within their environment presents a wide variety of situations. Removing the cover can be a difficult operation. Storage of the dismantled cover can also be dangerous for operators.

To this end, the applicant has developed a pressure device with a manhole for fluid comprising a manhole flange, a tight cover with the flange in the closed position and screws for fixing the cover to the flange in number greater than six regularly distributed in the vicinity of the outer edge of the cover and the flange. In the open position, the cover is hinged to the flange about an axis parallel to said screws and provided with an operating lever remote from said axis. Said screws pass through the holes in the cover, one of the holes having a first diameter, the other holes having a second diameter less than the first diameter. This provides the first diameter hole for mounting the hinge pin while preserving the threads. The cover in the open position can rest on the hinge pin in a stable low position providing great safety for the operator. The lever for rotating the cover around the axis allows maneuvering by a single cover operator whose mass can reach more than 100 kg for a diameter of 550 mm.

In one embodiment, in the open position, a stud passes through said hole of first diameter and at least partly supports the weight of the cover, the stud having a diameter less than the first diameter and greater than the second diameter.

In one embodiment, the stud comprises a radial surface bearing on the flange, a body having said diameter and a head with a diameter greater than the first diameter. The head retains the cover in the axial direction. The body forms a plateau. The radial surface resting on the flange reduces the torsional forces.

In one embodiment, said screws are permanently secured to the flange and, in the closed position of the cover, are engaged with nuts bearing on a surface of the cover opposite the flange. In this case, after the articulation axis, in particular the stud, has been fitted, and all the nuts have been removed, the cover is offset axially to release it from the screws secured to the flange. This can be done using the lever previously installed. Once axially offset by more than the length of the screws, the cover can be swiveled down. For this purpose, the stud body can be longer than the sum of the length of the screws and the thickness of the cover.

In another embodiment, the screws are removable and engage with a threaded hole in the flange.

In one embodiment, the cover is circular and the flange is annular. Alternatively, the cover is ovoid, rectangular and the flange is of corresponding shape.

In one embodiment, the number of screws is greater than twenty.

In one embodiment, the stud comprises a threaded blind hole in engagement, in the closed position, with one of said screws. Alternatively, the stud includes a threaded male part engaging in a threaded hole in the flange.

In one embodiment, the stud body has a length greater than the length of the screws protruding from the flange, increased by the thickness of the cover, so that the cover can be released from the screws while remaining on the stud.

The invention also provides a cover for a pressure vessel comprising a manhole flange. The cover is provided sealed with the flange in the closed position. The cover is provided with through holes in a number greater than six, for screws fixing the cover to the flange. Said through holes being regularly distributed in the vicinity of the circumference of the cover. The cover is provided with a member for receiving an operating lever. One of the holes has a first diameter and the other holes have a second diameter less than the first diameter, the operating lever being distant from the hole of first diameter. The cover can thus be easily operated.

In one embodiment, the operating lever is removable and perpendicular to the tax of said hole of first diameter.

In one embodiment, the operating lever is fixed by screwing in a blind hole formed in the cover perpendicular to the axis of said hole. The blind hole forms a receiving member.

In one embodiment, the operating lever is oriented at 120 ° to said hole of first diameter.

In another embodiment, the operating lever is fixed by at least two screws substantially parallel to said hole and provided on an outer surface of the cover.

In one embodiment, the cover further comprises two diametrically opposite operating handles and angularly offset relative to said hole of first diameter.

The invention also provides a method for operating a manhole cover for a pressure device, the cover being provided sealed in the closed position. The cover has more than six through holes for cover fixing screws. Said through holes are regularly distributed in the vicinity of the outer edge of the cover. The cover is fitted with an operating lever. The process includes the following stages in opening:

a) the release of a first screw disposed in a first hole having a first diameter, the other holes having a second diameter less than the first diameter;

- b) laying in said first hole of an axis parallel to said screws;

c) the release of the other screws;

d) pivoting of the cover around said axis using the operating lever releasing the manhole. The operating lever is distant from said axis.

In one embodiment, the installation of the operating lever takes place before step a).

In one embodiment, an axial offset of the cover takes place between steps c) and d).

In one embodiment, the lever is removed after step d).

In one embodiment, the method comprises, when closing, the pivoting of the cover around the axis using the operating lever. The force required is considerably lower than that which would be required by wearing the cover.

In one embodiment, the method comprises, when closing, the fixing by the other screws. The cover is thus stabilized in the closed position.

In one embodiment, the method comprises, on closing, removing from said first hole the axis parallel to said screws. At this stage, the cover is already immobilized by the other screws.

In one embodiment, the method comprises, when closing, the fixing by the first screw.

In one embodiment, in opening, after release of the first screw, a stud is placed in said first hole, the stud comprising a radial surface bearing on a body of a pressurized device, a stud body having a smaller diameter the diameter of the first hole and greater than the diameter of the other holes and a stud head with a diameter greater than the first diameter. The axial movement of the cover relative to the body of the pressure vessel is limited by the stud head.

In one embodiment, the screws being fixed, the cover is held in the closed position by nuts mounted on the screws. The nuts are supported on a surface of the cover opposite the body of the pressure vessel.

In one embodiment, a threaded blind hole in the stud is engaged with said screw.

In one embodiment, the cover is separated axially from the body of the pressure vessel and from the screws while remaining in contact with the stud body having a length greater than the length of the screws increased by the thickness of the cover. The cover is thus released from the screws while remaining on the stud.

The present invention will be better understood on studying the detailed description of an embodiment taken by way of nonlimiting example and illustrated by the appended drawings in which:

- Figure 1 is a general perspective view of a pressure device according to one aspect of the invention with a cover during operation;

- Figure 2 is a detail view of Figure 1 with the cover in the open position;

- Figure 3 is a detail view of Figure 1 with the cover in the separated position;

- Figure 4 is a detail view of the cover in the closed position;

- Figure 5 is an elevational view of the stud;

- Figure 6 is a detail view of Figure 1 with the stud in place.

In general, the interior of a pressure vessel for liquid and / or gas needs to be inspected to verify its condition and to be able to make repairs if necessary. In the case of a drinking water tank or pipe, the coating must maintain a high quality in order to maintain the potability of the water. In the case of a tank or an irrigation water pipe, the absence of corrosion inside the tank will be checked. In the case of loaded water, in particular waste water or unfiltered irrigation water, the absence of solid deposits and the absence of corrosion must be checked. This is the reason why from a certain size of pressure vessel, approximately 1000 liters for a tank, we choose to equip the pressure vessel with a manhole closed in the service position by a lid. The cover is often placed on a vertical wall of the pressure vessel while the pressure vessel has a horizontal or vertical main axis.

Pressure vessel means an organ capable of containing a fluid, static or in motion, at a pressure different from atmospheric pressure. After draining the pressure vessel, pressure equalization is carried out, for example by a vent valve, before opening the cover. Indeed, in the event of depression, the cover would remain pressed against the body of the pressurized device by atmospheric pressure while in the event of overpressure the opening of the cover would present an immediate danger to operators.

Seeking to facilitate inspection and maintenance operations during the life of a pressure vessel, the applicant has developed a cover which is simpler to operate and presents less danger to operators while reducing hand of necessary work. Indeed, for a manhole of 550 mm in diameter, the cover weighs more than 50 kg and can reach 100 kg or even more for pressure vessels subjected to a pressure of at least 25 bars or even at least 40 bars. The cover must then be removed to four operators during an inspection and then placed in safety to avoid an accident either by falling of the cover or by the fact that it forms an obstacle on the ground. Several types of accident risk can arise.

For this purpose, a secure maneuvering cover has been developed. As illustrated in Figures 1 to 5, the cover 1 comprises a circular panel 1 forming a cover body. The circular panel 2 is generally made of sheet steel with a thickness corresponding to the thickness of the body of the device under pressure, or even slightly greater and provided with an anti-corrosion coating. The circular panel comprises an external surface visible in the figures, an internal surface opposite the external surface and intended to be in contact with the liquid or the gas and a peripheral edge. The circular panel 2 is here substantially planar. Alternatively, it can be curved.

A plurality of through holes 3 are provided in the circular panel 2. The holes 3 extend from the exterior surface to the interior surface. The through holes 3 are uniformly distributed circumferentially. The through holes 3 are arranged near the peripheral edge of the circular panel 2. As shown, the through holes 3 are 30 in number. An excellent distribution of forces is thus obtained.

The through holes 3 are divided into two categories. The first hole 3a has a first diameter and the other holes 3b have a second diameter. The first diameter is greater than the second diameter. The first hole 3a can have a diameter between 8 and 30 mm, preferably between 12 and 24 mm. The other holes 3b can have the second diameter with a value between 4 and 24 mm, preferably between 10 and 20 mm.

The cover 1 comprises two diametrically opposite handles 4, for gripping the cover 1. The handles 4 can be in the general form of a U with a relatively flat bottom. The handles 4 are welded or screwed onto the circular panel 2, here on the peripheral rim. The handles 4 are angularly offset relative to the first hole 3a, for example from 20 to 40 °.

The cover 1 as illustrated in FIGS. 1 to 3 is also provided with a lever 5. The lever 5 comprises a straight rod of circular section. The length of the lever 5 is here substantially equal to the diameter of the circular panel 2. Preferably, the length of the lever 5 is provided to be able to handle several types of cover while not exceeding a lifting force of 350 N. The lever 5 is removably attached to the cover 1. The lever 5 thus forms part of the equipment of a monitoring or maintenance operator. The lever 5 is positioned on the cover 1 for the opening of the said cover 1 and then removed after the closing of the said cover 1. The lever 5 can be provided at its end, cooperating with the cover 1, with an external thread coming in taken in a tapped blind hole, not visible in the figures, formed in the thickness of the cover 1, in particular from its peripheral rim. The lever 5 can be positioned on the cover 1 at a location remote from the first hole 3a, for example 120 °, or between 120 ° and 180 °.

The pressure vessel 10 is here a reservoir. The pressure vessel 10 is here of horizontal axis. The pressure vessel 10 comprises a body 11 and feet 12. The body 11 has the shape of a cylinder of revolution 13 closed by rounded ends 14 and 15. The rounded end 14 is provided at its center with a flange 16. The flange 16 is in the form of an allowance for the rounded end wall 14. Alternatively, the flange 16 could be in the form of a collar. The flange 16 is annular. The flange 16 is, here, centered on the cylindrical axis 13. The body 11 can be made of welded sheets.

The opening 17 or manhole is formed in the center of the flange 16. The flange 16 supports screws 18 provided to cooperate with the holes 3 of the cover 1. The screws 18 are equal in number to the number of holes 3. The screws 18 are advantageously all identical. The screws 18 can have a threaded portion at the free end and a smooth portion near the flange 16. The screws 18 can be welded to the flange 16. Alternatively, the screws 18 can also be screwed into tapped holes, preferably blind , formed in the flange 16. In such a case, the screws 18 are then provided with a thread intended to cooperate with the threaded holes of the flange 16 and with a thread situated on the opposite side intended to cooperate with nuts. closing the cover 1. The nuts, not shown, may or may not have washers or protective members.

In the position illustrated in FIG. 1, the cover 1 is being maneuvered in the direction illustrated by the arrow directed downwards. For this purpose, the connection between the cover 1 and the pressure device 10 is provided by a stud 20 forming a pivot axis. The pin 20 is better visible in FIG. 6.

The stud 20 comprises a body in a cylinder of revolution 21 extending over a length greater than the sum of the thickness of the cover 1 in the region of the hole 3a and the length of the screws 18 projecting from the flange 16. The stud 20 also comprises a head 22 extending diametrically outward from one end of the body 21. The diameter of the head 22 is greater than the diameter of the body 21. The thickness of the head 22 taken in the direction of the length of the body 21 is relatively small insofar as the forces which can be exerted therein are moderate. The head 22 forms an axial stop for the cover 1 during the maneuver. The stud 20 also includes an end surface 23 opposite the head 22. The end surface 23 is radial. The end surface 23 forms a bearing surface on the flange 16, more precisely on the radial surface of the flange 16.

An at least partially tapped hole 24 is formed in the body 21 of the stud 20 from the radial surface 23. In the embodiment illustrated in FIG. 6, the hole ίο extends over substantially half the length of the stud 20. The hole 24 includes a smooth inlet portion and a threaded bottom portion. Such an arrangement can be provided to adapt to the screws 18 which may include a threaded portion at the free end and a smooth portion in the vicinity of the flange 16. The stud 20 is in one piece. The stud 20 can be made of steel.

Returning to FIG. 1, it can be seen that the stud 20 forms a pivot axis for the cover 2 during maneuver. The operation is carried out with lever 5. The stud 20 has been screwed onto the screw 18 projecting into the first hole 3a after removal of the corresponding nut.

In FIG. 2 is illustrated the position of the cover 1 at the end of the pivoting maneuver. The lever 5 is then in a vertical position down. The cover 1 releases almost all of the manhole 17. The cover is in a stable position, here a low position. The cover 1 rests on the pivot axis, here the stud 20.

To close the cover 1, one passes from the position illustrated in FIG. 2 with the full opening in the rest position to the position illustrated in FIG. 1 but in a direction of movement opposite to that of the arrow, then in the position illustrated. in Figure 3 and finally in the position illustrated in Figure 4. The cover pivots around the pivot axis.

In the position illustrated in FIG. 3, the cover 1 rests on the stud 20 and on the lever 5 and sees the other holes 3b located opposite the screws 18. In this raised cover position, the operator seeks to bring the screw 18 in the other holes 3b. The screws 18 are therefore not yet visible in the other holes 3b. Then when the cover is presented with the other holes 3b aligned with the screws 18, the cover 1 is pushed towards the flange 16 axially. In the position illustrated in FIG. 5, the cover has been pushed back several centimeters along the axis of the screws 18. The cover 1 is in contact with the flange 16. The screws 18 are inserted into the holes 3b and protrude from the side from the outer surface of the cover 1. The stud 20 also projects. The cover 1 can then receive the tightening nuts of the screws 18 projecting beyond the holes 3b.

Once all the nuts are arranged and screwed onto the screws 18 available, the stud 20 can be removed. The stud is removed by unscrewing. The head 22 of the stud 20 can be annular or hexagonal in shape and have the same dimensions as the nuts. It is thus possible to use the same tool for screwing the nuts and the stud 20. Then the corresponding screw 18, disposed in the first hole 3a, receives the last nut which can be tightened to the same torque as the other nuts for tightening uniform.

The lever 5 can also be removed in particular by unscrewing. To this end, the free end or an area adjacent to the thread of the lever 5 can also be provided with a hexagonal head of the same dimension as the head 22 of the stud 20 and the nuts of the cover.

1.

FIG. 4 makes it easier to see the difference in diameter between the first hole 3a and the other holes 3b. The other holes 3b receive the screws 18 and can be of diameter adapted to the non-threaded base portion of the screws 18. The first hole 3a sees the corresponding screw 18 and the stud 20 pass. The stud 20 is screwed onto said screw 18 has a diameter suitable for sufficient mechanical strength to bring the entire mass of the cover in axial contact with the head 22 of the stud 20. Thus, the diameter of the hole 3a is significantly greater than the diameter of the holes 3b.

The outside diameter of the body 21 of the stud 20 is very slightly less than the diameter of the first hole 3a so that the stud 20 can be inserted into the first hole 3a easily. The thickness of metal of the stud 20 between the external surface of the body 21 and the blind hole 24 is sufficient to ensure load transfer so that a portion of the radial end surface 23 is stressed in compression and the corresponding screw 18 in tensile stress when the cover 1 rests on the stud 20 near the head 22, see FIG. 2. This avoids subjecting the screw 18 located in the hole 3a to torsional forces which could deform it.

As can be seen in Figures 1 to 5, the cover 1 is positioned relative to the flange 16 and the screws 18 so that the first hole 3a and the stud 20 forming a pivot axis are located next to the screw 18 located lowest around the edge of the flange

16. However, the first hole 3a is disposed with an offset of a few screws, for example from two to four screws for a total of thirty screws, or angularly an offset of the order of 20 to 40 ° relative to the screw 18 la lower. This offset allows that, in the position of FIG. 3 where the operator seeks to position the cover 3 in order to fit the screws 18 into the holes 3b, the cover 1 does not have a tendency to tilt on the other side, which could surprise the operator and be dangerous due to the mass of cover 1.

In the opening direction, we first unscrew the nut mounted on the screw 18 disposed in the first hole 3a. The stud 20 is then screwed onto said screw 18 with tightening against the radial surface of the flange 16. The lever 5 is fixed. The lever 5 can be installed beforehand. Then proceed to unscrew the other nuts. The cover 1 then rests on the screws 18 and the stud 20 but is no longer retained in the axial direction, see FIG. 5. The operator can then, using the lever 5, take off the cover 1 from the flange 16 and the pull in a direction parallel to the screws 18 to disengage the screws 18 from the other holes 3b. The cover comes into axial abutment against the head 22 of the stud 20, see FIG. 3. The operator then retains the cover using the lever 5 and makes it descend progressively in the direction of the arrow illustrated in FIG. 1 until to reach the rest position in the open state illustrated in Figure 2. The inspection and maintenance of the pressure device 10 are then carried out.

Then, the reverse closing steps are implemented. First the cover 1 is raised by passing through the intermediate position illustrated in FIG. 1 to the position illustrated in FIG. 3 where the cover 1 has completed its rotation and is located with the other holes 3b opposite the screws 18 The cover 1 is then moved axially in the direction of the flange 16 to arrive at the position illustrated in FIG. 5. The screws 18 are then projecting relative to the holes 3b. The stud 20 can be unscrewed and removed. Then the last nut is screwed onto the screw 18 placed in the first hole 3a. The cover 1 is closed.

In one embodiment, the pressure manhole apparatus for fluid comprising an annular manhole flange, a sealed cover with the flange in the closed position and screws for fixing the cover to the flange in greater number to 6 regularly distributed in the vicinity of the outer edge of the cover and the flange, In the open position, the cover is hinged to the flange around a first of said to said screws and provided with an operating lever remote from said axis, said screws passing in holes made in the cover, the holes having the same diameter, said first screw having a length greater than the length of the others of said screws, the cover resting on said first screw while being released from the others of said screws. A nut placed on said screw can be unscrewed up to the vicinity of the end of said first screw for this purpose or a nut associated with a sleeve in the closed position of the cover can be removed and then repositioned without a sleeve.

In one embodiment, the pressure manhole apparatus for fluid comprising an annular manhole flange, a tight cover with the flange in the closed position and clamps in number greater than 6 regularly distributed over the in the vicinity of the outer edge of the cover and the flange, or a hoop fixing the cover to the flange. In the open position, the cover is hinged to the flange along an axis parallel to the flange and provided with an operating lever remote from said axis, said radial axis passing through a hole in the cover.

In one embodiment, the pressure manhole apparatus for fluid comprising an annular manhole flange, a sealed cover with the flange in the closed position and elements for fixing the cover to the flange regularly distributed at the near the outer edge of the cover and the flange. In the open position, the cover is hinged to the flange along an axis parallel to the flange and provided with an operating lever remote from said axis, said axis passing through a single through hole formed in the cover.

The invention is not limited to the examples of method and apparatus described above, only by way of example, but it encompasses all the variants that a person skilled in the art may envisage within the framework of the claims below. after.

Claims (10)

Claims 1. Pressure device (10) with manhole (17) for fluid comprising an annular manhole flange (16), a tight cover (1) with the flange (16) in the closed position and screws ( 18) for fixing the cover (1) to the flange (16) in a number greater than 6 regularly distributed in the vicinity of the outer edge of the cover (1) and the flange (16), characterized in that, in the open position, the cover (1) is articulated to the flange (16) along an axis parallel to said screws (18) and provided with a lever (5) for maneuver remote from said axis, said screws (18) passing through holes (3) provided in the cover, one of the holes (3a) having a first diameter, the other holes (3b) having a second diameter less than the first diameter. 2. Pressure apparatus according to claim 1, wherein, in the open position, a stud (20) passes through said hole (3a) and at least partially supports the weight of the cover, the stud (20) having a diameter less than first diameter and greater than the second diameter, and the stud (20) comprises a radial surface (23) bearing on the flange, a body (21) having said diameter and a head (22) of diameter greater than the first diameter. 3. Pressure apparatus according to one of the preceding claims, in which said screws (18) are permanently secured to the flange (16) and, in the closed position, are engaged with nuts bearing on a surface of the cover ( 1) opposite the flange (16), the cover (1) being circular and the screws (18) being more than 20 in number. 4. Pressure apparatus according to claim 3 taken with claim 2, wherein the stud (20) comprises a blind threaded hole (24) engaged, in the closed position, with one of said screws (18), and the stud body has a length greater than the length of the screws (18) projecting from the flange (16) so that the cover (1) can be released from the screws (18) while remaining on the stud (20). 5. Cover (1) of a manhole pressure device for fluid comprising a manhole flange, the cover (1) being provided sealed with the flange in the closed position, the cover (1) being provided with through holes (3) in number greater than 6, for screws for fixing the cover to the flange, said through holes (3) being regularly distributed in the vicinity of the outer edge of the cover, characterized in that the cover (1) is provided with a member for receiving an operating lever (5), one (3a) of the holes (3) has a first diameter and the other holes (3b) have a second diameter less than the first diameter, the lever maneuver (5) being distant from said hole (3a). 6. Lid according to claim 5, wherein the operating lever (5) is removable and perpendicular to the axis of said hole (3a) and is fixed by screwing in a hole in the cover (1) perpendicular to the axis of said hole (3a) and forming said member for receiving an operating lever. 7. Lid according to claim 5 or 6, further comprising two handles (4) for diametrically opposite operation and angularly offset with respect to said hole (3 a). 8. Method for operating a cover (1) of a pressure device (10) with a manhole for fluid, the cover (1) being provided sealed in the closed position, the cover (1) being provided with holes ( 3) through more than 6, for screws (18) for fixing the cover, said through holes (3) being regularly distributed in the vicinity of the outer edge of the cover, the cover (1) being provided with an operating lever (5), comprising at the opening: a) the release of a first screw disposed in a first hole (3a) having a first diameter, the other holes (3b) having a second diameter less than the first diameter; b) laying in said first hole (3a) an axis parallel to said screws (18); c) the release of the other screws; d) pivoting of the cover (1) around said axis using the operating lever (5) releasing the manhole (17), the operating lever (5) being mounted at a distance from said axis. 9. Method according to claim 8, comprising the installation of the operating lever (5) before step a), the axial offset of the cover (1) between steps c) and d), the removal of the operating lever ( 5) after step d). 10. Method according to claim 8 or 9, comprising on closing: a) pivoting of the cover (1) around said axis using the operating lever (5); b) fixing with the other screws; c) removing from said first hole (3a) the axis parallel to said screws (18); d) fixing with the first screw. 1/2