Packing case for reciprocating machine and method of assembling the same

A packing case for a plunger or a piston rod of a reciprocating machine comprises packing cups, each packing cup comprising a body with a hole for the passage of the plunger or rod and a sealing ring seat for housing a sealing ring which slidably bear against the plunger or rod. Packing cups are aligned with each other in series. The packing case comprises lube oil ducts for supplying lube oil from an end of the packing case to the sealing ring seat. Each packing cup comprises sectors, each sector comprising at least lube oil duct portions. The packing cups are positionable to bring, one sector at a time in an activation position where some of the lube oil duct portions of the sector are connected with the lube oil duct portions of an adjacent packing cup to form lube oil ducts. The packing cups are lockable.

BACKGROUND

Embodiments of the subject matter disclosed herein correspond to reciprocating machine, such as compressors and more particularly, but not exclusively, hypercompressors and packing cups and packing cases for those machines.

It is known that hypercompressors are reciprocating machines where a fluid is converted to an extremely high pressure (for example up to 3500 bar) because of a plunger compressing the fluid into a chamber; generally they can be single- or multi-staged.

It is known in the state of the art to arrange a sealing and jacket around the plunger or more generally around a piston rod of a reciprocating machine, like compressor or similar.

Such jacket usually comprises a packing case that in turn comprises a plurality of packing cups.

Packing cups usually have a disc-like shape and they are provided with a hole in the centre through which the plunger or rod passes when it reciprocates; the packing cups are assembled aligned and side by side with each other.

Each packing cup comprises plunger sealing rings intended to provide a seal on the plunger or rod; such plunger sealing rings have to be lubricated in order to avoid frictions and wear against the plunger or rod; to this end the packing case is provided with ducts intended for the passage of the lubricant; lube ducts are therefore housed in the packing cups.

For example, with reference to a packing case comprising five packing cups, it is assembled with a first packing cup adjacent to a distribution cup (usually remotely from the compressor chamber) followed by a second, third, fourth and fifth successive packing cups. Usually a ring carrier and a pressure breaker cup, adjacent to the compressor chamber are provided adjacent to the fifth packing cup.

Lubrication, for example, provides to bring the lubricant to the second and fourth plunger sealing rings (placed between the first and the second packing cups and between the third and the fourth packing cups respectively) and to further lubricate the region between the fifth packing cup and the ring carrier.

To this end lube oil ducts passing through one or more of the packing cups are provided.

In details, with reference to the known art just described, the duct intended to bring the lubricant to the second plunger sealing ring comprises an initial portion that passes through the distribution cup, an intermediate portion that parallel—with respect to the plunger axis—passes through the first packing cup and an end portion radial—with respect to the plunger axis—ending in the region to be lubricated.

Similarly, the duct intended to bring the lubricant to the fourth plunger sealing ring comprises an initial portion that passes through the distribution cup, an intermediate portion that parallel—with respect to the plunger axis—passes through the first, the second and the third packing cups and an end portion—radial with respect to the plunger axis—ending in the region to be lubricated.

Still similarly, the duct intended to bring the lubricant between the fifth packing cup and the ring carrier comprises an initial portion that passes through the distribution cup, an intermediate portion that parallel—with respect to the plunger axis—passes through the first, the second, the third, the fourth and the fifth packing cups and an end portion—radial with respect to the plunger axis—ending in the region to be lubricated.

From this situation it results that each packing cup, depending on its position in the packing case, houses (or not) one or more parts of the intermediate portion of the different ducts: the fact of placing the several packing cups side by side in the assembled condition causes the parts of the duct intermediate portions to be joined till forming the complete ducts.

The duct intermediate portions are made as through holes passing from one face to the other one of the packing cup, while the duct end portions are made as radial grooves (with respect to the plunger axis) connected to the relevant duct intermediate portions and ending at the region to be lubricated.

For instance, in the example just described, the first packing cup is provided with three holes: each one is a part of the intermediate portion of the first, second, and third ducts respectively intended to bring the lubricant to the second and fourth plunger sealing ring and in the region between the fifth packing cup and the ring carrier respectively.

The second packing cup is on the contrary provided with two holes: each one is a part of the intermediate portion of the second and third ducts respectively intended to bring the lubricant to the fourth plunger sealing ring and in the region between the fifth packing cup and the ring carrier respectively; the second packing cup is further provided with a radial groove, which is the end portion of the first duct.

The third packing cup is provided with two holes: each one is a part of the intermediate portion of the second and third ducts respectively intended to bring the lubricant to the fourth plunger sealing ring and in the region between the fifth packing cup and the ring carrier respectively.

The fourth packing cup is on the contrary provided with one hole as a part of the intermediate portion of the third duct intended to bring the lubricant in the region between the fifth packing cup and the ring carrier; the fourth packing cup is further provided with a radial groove, which is the end portion of the second duct.

Finally the fifth packing cup is provided with one hole as a part of the intermediate portion of the third duct intended to bring the lubricant in the region between the fifth packing cup and the ring carrier which, on its turn, comprises a radial groove.

From such exemplary situation it is easy to understand how each packing cup is unique, meaning that, once its position inside the packing case is established, it has to comprise certain ducts and no other ones.

Therefore, from the above, a first drawback of the known solutions is clear, which leads to produce each packing cup in a different manner depending on its position in the packing case; from this derives the need of having a plurality of single (first, second, third etc) packing cups in stock if it is necessary to replace one of them for maintenance reasons.

BRIEF DESCRIPTION

Therefore there is a general need for an improved packing case for reciprocating machines.

An important idea is to make the packing cups all equal to each other, and potentially to reduce manufacturing and warehousing costs.

Another important idea is a method of creating a plurality of service or auxiliary fluid ducts of different length and/or configuration in a machine, more particularly, a reciprocating machine, comprising the steps of: A) providing a plurality of modules incorporating one or more portions of duct, B) integrating the plurality of modules in a corresponding plurality of components, and C) positioning the components of said plurality adjacent to each other; wherein each of the components integrates a set of modules of different types; wherein at least one or only one of the modules of each component is used for creating service or auxiliary fluid ducts.

Embodiments of the subject matter disclosed herein correspond to a packing case for a reciprocating machine; such packing case is able to provide a seal along and around at least a part of a movable plunger or piston rod of the reciprocating machine; the packing case comprises a plurality of packing cups, each packing cup comprising on its turn a body with a hole for the passage of the plunger or rod and a sealing ring seat for housing a sealing ring which slidably bear against the plunger or rod to provide sealing; said packing cups are aligned with each other in series relative to the respective holes for the passage of the plunger or rod; the packing case comprises a plurality of lube oil ducts for supplying lube oil from an end of the packing case in an area of sealing ring seat.

According to the idea above, it is provided that all the packing cups are identical each other; each packing cup comprises sectors angularly offset with each other, each sector being provided at least by lube oil duct portions, the packing cups being selectively positionable with each other to bring, for each packing cup, one sector at a time in an activation position; in such activation position at least some of the lube oil duct portions of said sector is operatively connected with the lube oil duct portions of a sector in the activation position of an adjacent packing cup so as to form said lube oil ducts; once positioned, the packing cups can be locked each by each in a position corresponding to the activation position of a chosen circular sector.

In this way it is possible to have a packing case composed of all identical packing cups, which, during an assembly operation of the packing case, are placed, each by each, in different positions with respect to each other: in said positions one sector for each packing cup is activated (and—in use—supplied by lube oil) so that to form the whole lube oil ducts of the packing case itself.

It is therefore possible to overcome the above cited problems of the prior art, since it is possible to have only one kind of packing cup used for the entire packing case.

Manufacturing problems, availability and cost problems related to the known art have therefore brilliantly overcome by the above mentioned idea: only some lube oil duct portions for each sector of each packing cup will be active (that is, in fluid communication between one packing cup and another one and—in use—supplied by lubricant) and it will be possible to generate different paths of each lube oil duct by using always the same type of packing cup, suitably positioned before locking it in position, such to activate only one of the available sectors for each packing cup, depending to the position of the same packing cup in the packing case.

The remaining lube oil duct portions for each sector of each packing cup that are not in the activation position are not supplied by lubricant.

Embodiments of the subject matter disclosed herein correspond to a packing cup for a packing case of reciprocating machines, comprising a body with a hole for the passage of a plunger or rod of the reciprocating machine, said hole having a first longitudinal axis, a sealing ring seat for housing a sealing ring which slidably bear against the plunger or rod to provide sealing, wherein the packing cup comprises sectors angularly offset with each other, each sector being provided at least by lube oil duct portions, in each sector of the packing cup a plurality of available positions being grouped, every available position of such plurality being lined on the same circumference having its center on said first axis, each available position of such plurality being used for one between: an axial lube oil duct portion extending between opposed faces of said packing cup, a radial lube oil duct portion, more particularly a radial groove, extending radially to the sealing ring seat of the packing cup, a stopping wall, in which, for each packing cup, the number of sectors is at least equal or major than the number of available positions of each sector, in which different sectors of the same packing cup have said available positions used for a number of axial lube oil duct portions decreasing from a maximum number equal to the number of sectors, at least one of the remaining available positions of each sector being used for a a radial lube oil duct portion, more particularly a radial groove.

Embodiments of the subject matter disclosed herein correspond to a reciprocating machine, in particular a compressor, an hypercompressor or the like, provided by such a packing case.

DETAILED DESCRIPTION

The following description of exemplary embodiments refers to the accompanying drawings.

The following description does not limit the invention. Instead, the scope of the invention is defined by the appended claims.

According to the idea herein described, the method of creating a plurality of service or auxiliary fluid ducts of different length and/or configuration in a machine, more particularly a reciprocating machine, comprising the steps of: A) providing a plurality of modules incorporating one or more portions of duct, B) integrating the plurality of modules in a corresponding plurality of components, and C) positioning the components of said plurality adjacent to each other; each of the components integrates a set of modules of different types and at least one or only one of the modules of each component is used for creating service or auxiliary fluid ducts.

In general such service or auxiliary fluid ducts can be oil or lubricant or also different fluid that reach different areas of the machine by following a plurality of fluid ducts.

In an embodiment, each of the components integrates a set of modules of different types at a corresponding set of angular positions; and, at step C above, each of the components is rotated before being positioned so as to align at least one or only one of its modules with at least one or only one of the modules of adjacent components.

In an embodiment, all of the components of said plurality are identical and each of the components of said plurality integrates the same set of modules of different types.

In the following said a method will be described with reference to the attached figures; in the exemplary embodiment herein below described, the above mentioned “components” are embodied by packing cups, “modules” are embodied by sectors, and the service or auxiliary fluid is oil or lubricant.

With reference toFIG. 1enclosed, a sectional view of part of a reciprocating machine provided with a packing case according to a first embodiment is shown.

The packing case1serves for providing a seal along and around at least a part of a movable plunger2(or piston rod) of the reciprocating machine (not shown in its entirety).

The packing case1comprises at least a plurality of packing cups, in this non limiting example there are five packing cups11A-11E, although a different number of them is provided in different embodiments (not shown) of the subject matter herein disclosed.

The packing case1further comprises a distribution cup5, adjacent to a first packing cup11A, and a ring carrier6, adjacent to the last packing cup11E.

The distribution cup5is provided by one fixed lubricant supply duct51, on its turn coupled with a lubricant source (not shown) such a lubricant tank, a lubricant pump, a lubricant piping or similar.

With reference also toFIGS. 2 and 3, each packing cup11A-11E comprises a body12with a hole13for the passage of the plunger or rod2.

The shape of the body is circular, as shown, with the hole13having the same center of the body; more in general, other different shapes than the ones shown here could be also used.

Each packing cup11A-11E further comprises a sealing ring seat14for housing a sealing ring15(seeFIG. 1). The latter surrounds the hole13for the plunger2and, in an assembled condition, slidably bear against the plunger2itself to provide sealing.

As can be best seen inFIG. 1or in the exploded view ofFIG. 4, in the packing case1the packing cups11A-11E are aligned with each other in series relative to the respective holes13for the passage of the plunger or rod2.

The packing case1further comprises a plurality of lube oil ducts A, B, C for supplying lube oil (or—more generally—lubricant) from an end of the packing case in an area of the sealing ring seat14, in order to lubricate the latter and/or the sealing ring15.

In the non limiting example, there are three lube oil ducts A, B, C (see alsoFIG. 5): a first lube oil duct A for supplying lubricant into an area of the (second) sealing ring seat14of the second packing cup11B, a second lube oil duct B for supplying lubricant into an area of the (fourth) sealing ring seat14of the fourth packing cup11D a third lube oil duct C for supplying lubricant into an area between the fifth packing cup11E and the ring carrier5.

According to the idea herein described, and as can be seen inFIG. 4, all the packing cups11A-11E of the packing case1are identical each other, so as obtain the above mentioned advantages.

To this extent and for allowing to create the different lube oil ducts A,B,C, each packing cup11A-11E comprises sectors31,32,33angularly offset with each other, each sector31,32,33comprising at least lube oil duct portions41,42.

InFIGS. 2 and 3only the packing cup11A is shown, the remaining being identical to this one.

Particularly, inFIG. 3, such sectors31,32,33are highlighted by means of dashed lines indicating their position on the packing cup11A; inFIG. 2the sectors31,32,33, though not highlighted, are nevertheless present, since those “sectors” are merely areas of the packing cup11A itself.

The packing cups11A-11E are selectively positionable with each other to bring, for each packing cup11A-11E, one sector31,32,33at a time in an “activation position”.

Particularly, when each sector is a circular sector31,32,33, the packing cups11are selectively positionable with each other by means of a rotation around a first axis coincident to a central longitudinal axis X of the hole13for the plunger or rod2.

In the activation position at least some of the lube oil duct portions41,42of said sector31,32,33are operatively connected with the lube oil duct portions41,42of a sector31,32,33in the activation condition of an adjacent packing cup11A-11E so as to form said lube oil ducts A, B, C.

During operation, the lube oil duct portions41,42that are in the activation position are supplied by lubricant by means of the fixed lubricant supply duct51of the distribution cup5; remaining oil duct portions of sectors in a non-activation position (every position different than the activation position) are not supplied by lubricant or oil.

The packing cups11A-11E are then lockable each by each at one position corresponding to the activation position of a circular sector31,32,33of the packing cup, in a way that will be described later on.

More particularly, for each sector31,32,33of each packing cup11A-11E a plurality of available positions are grouped, every available position of such plurality being lined on the same circumference having its center on said first axis X.

Looking atFIG. 3, for clarification extent, there are highlighted, for two sector, namely31,33, the available positions, shown as dashed circles; available positions are therefore areas of one sector that are lined on the same circumference having its center on said first axis X.

All the available positions of all the sectors are on the same circumference, while all such circumferences of different packing cups have all the center on the first axis X and the same radius.

Each available position of such plurality is used for one between: an axial lube oil duct portion41, extending between opposed faces of the packing cup11A-11E, a radial lube oil duct portion, extending radially to the sealing ring seat14of the same packing cup11A-11E, a stopping wall43.

The radial lube oil duct portion is a radial groove42.

For example, looking atFIG. 3, sector31has all the available positions (three in this example) used for axial lube oil duct portions41, while sector33has one available position used for an axial lube oil duct portion41, one used for a radial groove42and one used for a stopping wall43. The remaining sector32(in which the available positions are not highlighted) has two available positions used for a axial lube oil duct portions41and one used for a radial groove42.

During an assembly operation of the packing case1, the packing cups11A-11E are placed, each by each, in different (in this example, angular) positions with respect to each other: in said positions one sector for each packing cup is activated (and—in use—supplied by lube oil), and, in major detail, at least some of the duct portions41,42of said sector are supplied by oil or lubricant: in this way, activating only one of the available sectors for each packing cup (depending to the position of the same packing cup in the packing case), it is possible to realize the whole lube oil ducts A, B, C of the packing case1itself.

More particularly, for each packing cup11A-11E, the number of sectors31-33is at least equal, or major, than the number of available positions of each sector; to this extent inFIG. 4there is shown in dashed lines an additional, optional, spare sector, which, in this example is not in use.

It has to be noted that different sectors31,32,33of the same packing cup11have said available positions used for a number of axial lube oil duct portions41decreasing from a maximum number equal to the number of lube oil ducts A, B, C of the packing case1.

So, for example, if the number of lube oil ducts A, B, C is three, then there will be a sector having three axial lube oil duct portions41, another sector having two axial

lube oil duct portions41, and another sector having one axial lube oil duct portions41.

In this case, at least one of the remaining available positions of each sector31,32,33is used for a a radial lube oil duct portion, such as a radial groove42.

When assembling the packing case1, the packing cups11A-11E as described are assembled, starting from a first packing cup11A until a last packing cup11E, and the first packing cup11A has in the activation position a sector,31, having a maximum number of axial lube oil duct portion41, while the last packing cup11E has in the activation position a minimum number of axial lube oil duct portion41.

Remaining intermediate packing cups11B,11C,11D between the first11A and the last11E packing cup, have in said activation position, sectors31,32,33provided by a number of axial lube oil duct portion41equal or less that the ones41of the immediately preceding packing cup in a progression starting from the first11A to the last11E packing cup.

In this way it is possible to align axial lube oil duct portion41of adjacent packing cups11A-11E for realizing a number of lube oil ducts A, B, C that decreases from the first11A to the last11E packing cup of said packing case1.

In this way, as can best be seen inFIG. 5, each lube oil duct A, B, C is formed by lube oil duct portions41,42of different packing cups sectors in the activation position: particularly each oil duct A, B, C comprises one or more axial lube oil duct portions41and one radial groove42.

It can be noted in the non limiting example, that lube oil duct A is formed by one axial lube oil duct portions41(of packing cup11A) and one radial groove42(of packing cup11B); lube oil duct B is formed by three axial lube oil duct portions41(of packing cup11A,11B,11C) and one radial groove42(of packing cup11D); lube oil duct C is formed by five axial lube oil duct portions41(of packing cup11A-11E) and one radial groove42(provided on the ring carrier6).

Looking at the figures, in the non limiting example of the present embodiment, the whole number of lube oil ducts decreases from three to one starting from the first packing cup11A to the last11E.

In operation, the lube oil duct portions41,42in the activation position of the first packing cup11A are aligned with the fixed lubricant supply duct51of the distribution cup5, so that they can be supplied by the latter; the fixed lubricant supply duct51can be either in form of one single duct, or in form of a multiple channel duct.

As a matter of fact, in this preferred embodiment, the packing comprises five packing cup and three lube oil ducts A,B,C, and, in turn, each packing cup11comprises a first31, a second32and a third33angularly offset circular sectors.

In this embodiment, the first circular sector31comprises three axial portions of lube oil ducts41, the second circular sector32comprises two lube oil duct portions41and a radial lube oil duct portion, more particularly a radial groove42, and the third circular sector33comprises one lube oil duct portion41, one radial lube oil duct portion, more particularly a radial groove42and one stopping wall43.

In an embodiment, when no spare sectors are provided and in the case of three sectors as already described, the third33circular sector is arranged between the second32and the first circular sector31, rotated by 90° with respect to both of them.

It has to be noted that, in the preferred solution, the axial portion of the lube oil duct41comprises a through hole passing between two opposite faces of the body12of the packing cup11A-11E arranged parallel to the first axis of the hole13for the plunger or rod2and the radial lube oil duct portion42comprises a groove made on a face of the body12of the packing cup11A-11E and arranged radially with respect to the first axis of the hole13for the plunger or rod.

In an embodiment, the body12of each packing cup11A-11E comprises a packing cup internal part12A and a packing cup external part12B surrounding the packing cup internal part.

Said two part12A and12B can be separated and coupled together to the extent of forming the body12.

In this embodiment, sectors31,32,33are provided at said packing cup internal part12A, as shown in the figures.

In order to lock in position the packing cups11A-11E, blocking elements are provided; said blocking elements are suitable for coupling each packing cup11A-11E with at least one between the distribution cup5or the ring carrier6.

More particularly, looking atFIG. 4, as in the example shown, such blocking elements are suitable for coupling each packing cup11A-11E with the distribution cup5.

More particularly, the blocking elements comprises at least one, in an embodiment two, tie rod71and respective tie rod seats72of each packing cup11A-11E, in which the tie rod71is housed.

Still more particularly, the blocking elements comprises also at least one, in an embodiment two, locating pin73, which helps in the assembly operation.

Each packing cup11A-11E comprises at least one, more particularly more than one, still more particularly four, tie rod seats72so to allow for locking the packing cups11A-11E in a preferred angle position.

In this non limiting example each packing cup11A-11E can be locked in position at interval of 45° of rotation, so as to have one chosen sector at a time in the activation position.

The packing case1, in operation, will be cooled.

Reference is made now toFIGS. 6 and 7.

In an embodiment, in the assembled condition, at least between the packing cup external parts12B of a pair of adjacent packing cups11A-11E a passageway91is provided for a fluid coolant, that, in this way, became in contact with a large surface area of the packing cup external parts12B, for a better cooling effect.

This can be obtained, for example, by having a different thickness between the body external part12B and the internal part12A, as shown in the detail ofFIG. 7.

In an embodiment, body internal parts12A of each packing cup11A-11E are in contact each other when the packing case1is assembled; the thinner external parts12B of each packing cup11A-11E in this condition rests at a certain distance, so creating the passageway91, in which fluid coolant can pass.

The packing case1further comprises an external sheath8, that in the example ofFIG. 6, houses the packing cups11A-11E as well as the ring carrier6and part of the distribution cup5, which closes one end of the external sheath8.

The external sheath8is provided at least by a coolant inlet81, in operation connected to a coolant source, and by a coolant outlet, in operation connected to a coolant discharge.

For allowing fluid coolant passing into contact with the major area of the packing cups, so as to maximize the cooling effect, a labyrinth like flow path of the coolant is provided (shown by arrows ofFIG. 6).

To this extent each packing cup11A-11E is provided by coolant holes92, shown also inFIG. 2; coolant holes92are through holes passing between two opposite faces of the body external part12B of each packing cup11A-11E, still more particularly arranged parallel to the first axis of the hole13for the plunger or rod2.

When the packing cup is assembled, coolant holes92are in fluid communication with the passageway91formed between two adjacent packing cups11A-11E.

In order to realize the labyrinth like flow path, plugs93are provided, that closes only some coolant holes92of a packing cup11A-11E: for example closing by plugs93alternatively positioned holes92of two adjacent packing cups, the coolant flows in the passageway91in contact with substantially the entire surface of the two adjacent packing cups, for an optimal cooling.

Using plugs93allows to close only chosen holes92in function of the angular position of each packing cup and its position in the packing case1.