DE102012022576B4 - Safety valve group - Google Patents

Abstract

A safety valve assembly (10) comprising: a body defining a flow path between an inlet (11) and an outlet (12) for a liquid aligned along a longitudinal axis; a first shut-off valve (13, 13 *) for the Liquid level with the side of the entrance (11); and a second shut-off valve (15) on the side of the outlet (12); a check valve (14) between the first and second shut-off valves (13, 13 *, 15); anda safety valve (17) against excess pressure at the level of the outlet (12) of the safety valve group (10); wherein the safety valve group (10) is provided with at least one viewing opening for the check valve (14) which is closed by a removable plug (20) , wherein the first and second shut-off valve (13, 13 *, 15) and the check valve (14) are aligned along the longitudinal axis of the safety valve group (10); wherein the second shut-off valve (15) is a three-way ball valve that has an auxiliary outlet (16 ) for the safety valve (17); and wherein the second shut-off valve (15) has a ball lock (15 ') which is formed with a main passage (24) and two branched passages (25, 26), the ball lock (15') ) of the second shut-off valve (15) can optionally be brought into two operative positions and in an optional third position, wherein: in a first operative position it connects the output (12) to the input (11) of the safety device eitsventilgruppe (10) connects via the main passage (24) and connects the main passage (24) to the auxiliary outlet (16) for the safety valve (17) via a first branched passage (25); in a second operative position it connects the outlet (12) the safety valve group (10) with the auxiliary outlet (16) for the safety valve (17) via the two branched passages (25, 26) and closes to the check valve (14); while in the optional third position to the outlet (12) of the The safety valve group (10) closes and a connection between the safety valve (17) and the check valve (14) is maintained via the branched passages (25, 26).

Description

BACKGROUND OF THE INVENTION

The present invention relates to a safety valve group which is suitable for connecting a storage tank for pressurized water to a source of domestic water, and is designed to protect the water tank from overpressure and to carry out control and maintenance measures under perfectly safe conditions for to be able to carry out by the operator.

STATE OF THE ART

As is known, modern heating systems in the private and / or industrial sector include an auxiliary circuit for heating and for distributing hot water to several consumers. In general, the heating and water distribution circuit comprises a pressurized storage tank, for example a boiler, connected to a water supply network or to a source of cold domestic water for normal replenishment during the consumption of hot water.

Some applicable regulations, in particular EN 1488, require that the water storage tank be connected to the water supply network via a safety valve group that includes a non-return valve that is suitable for preventing the water from flowing back from the storage tank to the water supply network so that possible causes of pollution are avoided .

The relevant regulations also stipulate that the check valve must be isolated by suitable shut-off valves in order to check the tightness and function of the check valve via appropriate inspection openings; a safety valve is also required on the downstream side of the valve group in order to protect the storage tank from excess pressure.

Safety valve groups, for example, are noisy EP 1 229 291 A2 and EP 1 681 520 A2 known; In both cases, the valve group comprises a shut-off valve on the inlet side, a shut-off valve on the outlet side and a check valve in between, which are arranged along a "U" -shaped path that runs vertically downwards, a small distance between the inlet port and the Keep output connection; The check valve with the associated inspection opening is aligned vertically in a position below the shut-off valve on the inlet side. In addition, the valve group in both documents is equipped with a safety valve against excess pressure, which is arranged after the shut-off valve on the outlet side of the valve group which is directly connected to the water storage tank.

A similar U-shaped configuration and the arrangement of the valves in both documents make it possible, on the one hand, to reduce the distance between the inlet connection and the outlet connection of the valve group, but lead to a complicated structure and a greater height expansion with the resultant greater space requirement for the entire valve group. In addition, the arrangement of the safety valve after the check valve on the outlet side in direct connection with the storage tank for the pressurized water does not allow a control and / or replacement of the safety valve to be carried out, since this intervention would entail considerable dangers for an operator.

From the DE 25 19 211 A1 a shut-off valve with a backflow preventer is known. In order to reduce the space requirement for the shut-off valve and to achieve a favorable hydraulic resistance value, it is disclosed herein that the closure member of the shut-off valve is hollow.

The FR 2 676 530 A3 discloses a valve unit for the distribution of hot water in a circulation circuit and a hot water supply circuit. For this purpose, the valve unit comprises two ball valve valves which can be moved between a fully open and a fully closed position. The ball valve valves are arranged with a fixed intermediate axis and are provided with a bypass line so that both circuits can be connected to the same water distribution network.

OBJECTIVES OF THE INVENTION

The aim of the present invention is to provide an improved safety valve group by means of which the disadvantages of the known valve groups can be eliminated.

In particular, the aim of the invention is to provide a safety valve group with an extremely compact structure, in which the distance between the inlet and outlet connections is significantly reduced and which enables the valve to be protected against overpressure under completely safe conditions, without any danger to one Control and / or replace operators.

Another object of the invention is to provide a safety valve group in which the control and / or replacement of the valve against excess pressures by closing in the direction of the Storage container can only be carried out by an authorized operator.

Yet another aim is to offer a valve group as described above in which the pressure losses are comparatively lower, in which the checking and / or replacement of the check valve is extremely easy for an operator and in which the safety valve against excess pressures is always operational is connected to the storage tank, both during normal operation of the group and when checking and / or replacing the non-return valve, whereby water can also be taken from the storage tank for a possible control and / or replacement.

BRIEF DESCRIPTION OF THE INVENTION

The objectives described above can be achieved by a safety valve group having the features according to claim 1. Preferred embodiments are specified in the dependent claims.

In particular, in accordance with the present invention, there has been provided a safety valve assembly for protecting a storage container which can be connected to a source of pressurized liquid.

According to a first preferred embodiment, a reduction in the length of the safety valve group is made possible by creating the flow path with a curved section between the check valve and the second shut-off valve, a viewing opening being provided in front of the check valve at the level of the curved section.

According to a further preferred embodiment, both the first shut-off valve and the second shut-off valve are both three-way ball valves, which are designed identically with an additional connection and both are equipped with a ball lock that has a main passage and two branched passages that are arranged at right angles to one another and can be angularly aligned in two operative and in an optional third position, as previously described, in which the flow path comprises a lateral viewing port which is axially aligned and in communication with the first shut-off valve.

Figure list

• ein Kreislaufschema ist, das die Verbindung eines Speicherbehälters für Heißwasser mit dem Wasserversorgungsnetz durch die erfindungsgemäße Sicherheitsventilgruppe darstellt;
• eine perspektivische Ansicht der Sicherheitsventilgruppe gemäß einer ersten Ausführungsform ist;
• ein Längsquerschnitt mit beiden Absperrventilen in geöffnetem Zustand ist, um die Verbindung des Speicherbehälters mit dem Wasserversorgungsnetz zu ermöglichen;
• ein ähnlicher Querschnitt wie in mit dem vorgeschalteten ersten Absperrventil in geschlossenem Zustand und dem nachgeschalteten zweiten Absperrventil in offenem Zustand ist, um die Dichtigkeit des Rückschlagventils zu überprüfen;
• ein ähnlicher Querschnitt wie in mit beiden, in Richtung Rückschlagventil geschlossenen Absperrventilen ist, um dessen Austausch zu ermöglichen;
• ein ähnlicher Querschnitt wie in mit dem vorgeschalteten ersten Absperrventil ist, das in Richtung Rückschlagventil geschlossen ist, und mit dem nachgeschalteten zweiten Absperrventil, das in Richtung Ausgang der Sicherheitsventilgruppe geschlossen ist, um eine Kontrolle und/oder einen Austausch des Sicherheitsventils gegen Überdrücke zu ermöglichen;
• , und perspektivische Ansichten des Kugelverschlusses des nachgeschalteten zweiten Absperrventils in den beiden operativen Positionen von , und und in der optionalen Position von sind;
• ein ähnlicher Querschnitt wie in für die zweite Ausführungsform der erfindungsgemäßen Sicherheitsventilgruppe ist.

Both preferred embodiments of the safety valve group according to the invention are described more clearly below with reference to the examples in the accompanying drawings, wherein:

• Figure 13 is a circuit diagram showing the connection of a hot water storage tank to the water supply network through the safety valve assembly of the invention;
• Figure 3 is a perspective view of the safety valve assembly according to a first embodiment;
• is a longitudinal cross-section with both shut-off valves in the open state to enable the connection of the storage tank to the water supply network;
• a similar cross-section as in with the upstream first shut-off valve in the closed state and the downstream second shut-off valve in the open state in order to check the tightness of the non-return valve;
• a similar cross-section as in with both shut-off valves closed in the direction of the non-return valve to enable its replacement;
• a similar cross-section as in with the upstream first shut-off valve, which is closed in the direction of the non-return valve, and with the downstream second shut-off valve, which is closed in the direction of the outlet of the safety valve group, in order to enable a control and / or replacement of the safety valve against excess pressure;
• , and perspective views of the ball lock of the downstream second shut-off valve in the two operative positions of FIG , and and in the optional position of are;
• a similar cross-section as in for the second embodiment of the safety valve group according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

As schematically in As shown, the safety valve assembly indicated generally at 10 includes a housing defining a flow path extending along a longitudinal axis between an inlet 11 on the upstream side and an exit 12 extends on the downstream side. The entrance 11 can be connected to a water supply network I or another source of cold water for domestic water, while the output 12 with a storage tank SA for storing pressurized water, for example hot service water, can be connected, which comprises a heat exchanger which is connected to a hot water source ST and a hydraulic circuit for supplying the various consumers U.

The safety valve group 10 comprises a first shut-off valve designed as a ball valve 13 to shut off the water flow on the side of the entrance 11 , a check valve 14th in an intermediate position and a second shut-off valve designed as a ball valve 15th to shut off on the side of the exit 12 , in which the second shut-off valve 15th a branched auxiliary output 16 for a safety valve 17th which is normally provided to have an output 18th to drain part of the hot water contained in the storage tank SA in the event of excess pressure; the safety valve 17th can be of any desired type.

The two shut-off valves 13 and 15th are opened and closed by appropriate control handles 13E and 15E to operate on the bottom of the safety valve group 10 are positioned.

As in and in cross section of shown, the safety valve group 10 has a linear geometric configuration in which the two shut-off valves 13 and 15th and the check valve 14th aligned along a longitudinal axis extending from the port of the entrance 11 and the connection of the output 12 is defined; in addition, it can also be seen in the above figures that between the first shut-off valve 13 and the check valve 14th the flow path has a curved section 19th which allows the linear arrangement of the three valves 13 , 14th , 15th definitely maintain while keeping the distance between the entrance 11 and the exit 12 the safety valve group 10 to reduce.

The special linear design of the safety valve group 10 with the curved section 19th , combined with a special shape of the flow passages in the ball locks 13 ' , 15 ' of the two shut-off valves 13 and 15th , as will be described later, was designed to achieve high flow rates and a high flow coefficient Kv in an extremely small space, as well as the check valve 14th to be positioned between viewing openings by means of removable plugs 20th and 21st are closed, which are easily accessible to an operator; in particular is the top plug 20th to open the upper inspection opening at the level of the curved section 19th the housing of the safety valve group 10 positioned while the lower plug 21st in an aligned position under the check valve 14th is located.

As in shown is the ball lock 13 ' of the first shut-off valve 13 on the side of the connection of the entrance 11 or before the safety valve group 10 formed with an L-shaped inner passage, which is connected accordingly and located between the two openings arranged at an angle of 90 ° to one another 13A and 13B extends; the first side opening 13A lies in one to the axis of rotation 22A of the ball lock 13 ' parallel plane that is at right angles to the longitudinal axis of the housing of the safety valve group 10 is to go with the entrance 11 to be associated while the second upper opening 13B in one to the axis of rotation 22A perpendicular plane and with the left side of the curved section 19th is connected.

Also in note that the check valve 14th at the level of the right side of the curved section 19th in an intermediate position between the two shut-off valves 13 and 15th is. Also has the check valve 14th its axis at right angles to the longitudinal axis of the safety valve group 10 arranged to be inserted and removed through a specially provided lower opening. The check valve 14th is located in a seat provided for this purpose, through a main plug 23 is closed, which is formed with a lower inspection opening through a plug 21st is locked.

With reference to to it should be noted that the ball lock 15 ' of the second shut-off valve 15th on the side of the exit 12 with multiple flow passages designed to occupy three different angled positions, in particular two operative positions shown in , and and an optional third item shown in is shown. In the first operational position in and is the second shut-off valve 15th both to the check valve 14th as well as to the exit 12 the safety valve group 10 via a main passage 24 between the two openings 15A and 15B and also to the safety valve 17th through a first branched passage 25th and the opening 15C open; in the third or optional position, on the other hand, that in is the second shut-off valve 15th to the check valve 14th closed while the connection of the storage tank SA with the safety valve 17th via the two branched paths of the culverts 25th , 26th and the openings 15C and 15D remains upright, as explained in more detail below.

The features of the ball lock 15 ' of the second shut-off valve 15th are in the perspective views of , and shown in more detail which the ball lock 15 ' in show three angular positions previously indicated.

Out shows that the ball lock 15 ' of the second shut-off valve 15th with a first, with the arrows 24 specified main passage is formed, which is located diametrically between two opposite openings 15A , 15B in one to the axis of rotation 22B ( ) perpendicular direction extends to the opening of the safety valve group 10 and circulating the water flow from the port of the inlet 11 to connect the output 12 and to enable storage tank SA for storing hot water according to the example used.

The ball lock 15 ' also includes a side opening 15C that in one to the axis of rotation 22B right-angled plane and a first, with the arrow 25th specified branched passage to the auxiliary outlet 16 for the safety valve 17th forms; the main passage 24 also has a side opening 15D in connection, the one second, with the arrow 26th specified branched passage, which in one to the main passage 24 parallel plane and to the check valve 14th is orientable.

The , in which the same reference numbers as in used to designate similar or equivalent parts, shows the ball lock 15 ' in a second angled position compared to that by 90 ° in a first, from the arrow W1 direction indicated is rotated in which it is to the check valve 14th towards closes and on the other hand the connection between the output 12 and the safety valve 17th via the two branched passages 26th and 25th maintains.

The , which also has the same reference numbers as in and were used to designate similar or equivalent parts, finally shows the ball lock 15 ' in a third angled or optional position that is 90 ° in the opposite direction to that of is rotated and with the arrow W2 is indicated in which he is heading towards the exit 12 and closes in the direction of the storage tank SA, the connection between the check valve 14th and the safety valve 17th via the two branched passages 25th and 26th is retained.

Previously it was said that the ball lock 15 ' of the second shut-off valve 15th on the downstream side or side of the exit 12 the safety valve group 10 can take a third angled position or optional position in which to face the exit 12 the safety valve group 10 and consequently closes towards the storage container SA.

This second closed state of the second shut-off valve 15th serves together with the closing of the upstream first shut-off valve 13 in addition to the connection of the safety valve group 10 to shut off the storage tank SA when an authorized operator has to intervene to open the safety valve 17th to review and / or replace.

To prevent the ball lock 15 ' of the downstream second shut-off valve 15th is accidentally or intentionally turned to the optional third position by an unauthorized operator, the second shut-off valve has been activated 15th provided with locking means that can be released with a special tool to allow rotation of the control handle 15E into the optional position of the ball lock 15 ' and to only allow them in the two operational positions indicated above.

The locking means of the control handle 15E can prevent the ball lock from rotating 15 ' be somehow shaped into the optional third position; in the example used, they consist of the control handle 15E with two teeth at an angle 27 and 28 is provided that have a locking tooth 29 can interact with the housing of the safety valve group 10 is firmly connected. The two teeth 27 , 28 and the locking tooth 29 are designed and positioned to fit the control handle 15E and consequently the ball lock 15 ' allow you to move 90 ° between the in shown open state of the valve 15th and the in shown, to the check valve 14th to turn closed state.

The control handle 15E is also on the axis of rotation 22B of the ball lock 15 ' with a special screw 30th attached whose head 31 is shaped to enable it to be screwed on and unscrewed by a special, similarly shaped tool which is only made available to an authorized operator.

The functioning of the safety valve group 10 in accordance with the present invention will now be described with reference to the various figures of FIGS. 2-9.

As mentioned earlier, the invention is directed to a safety valve assembly 10 , which is suitable, for example, both to connect a pressurized storage tank SA for storing hot water to a water supply network I or another service water source, as well as to protect the same storage tank SA against overpressures and also to prevent the hot water from flowing back Storage tank SA to the water supply network I through the same safety valve group 10 and always a connection with the safety valve 17th to maintain.

If, as in shown, both shut-off valves 13 and 15th are open, the water entering from the water supply network I will flow to the storage tank SA through the check valve 14th allows to supplement the consumption of hot water delivered to the user U; at the same time, any overpressures that may occur in the storage tank SA are released via the safety valve 17th derived, causing a dangerous backflow of hot water from the storage tank SA to the water supply network I through the check valve 14th is prevented.

When you look at the tightness of the check valve 14th need to check as in shown is the first shut-off valve 13 on the side of the entrance 11 by operating the control handle 13E closed while the second shut-off valve 15th on the side of the exit 12 both to the SA storage tank and to the safety valve 17th is kept open; in this way it is for example by removing the stopper 20th , which closes the inspection opening, it is possible to check the tightness of the check valve 14th perform; Another check could be by removing the plug 21st respectively.

When doing maintenance work and / or replacing the check valve 14th must perform, the ball locks 13 ' and 15 ' both shut-off valves 13 and 15th in the in shown closed position rotated in which the ball lock 15 ' 90 ° with respect to the open position of in the direction of the arrow W1 is rotated as referring to FIG and specified; in this state, any flow of water becomes the check valve 14th from the side of the entrance 11 and from the side of the exit 12 prevented, but a connection between the connection of the output 12 and the branched auxiliary output 16 of the safety valve 17th persists.

In this state in which both shut-off valves 13 and 15th closed, it is also possible to remove the main plug 23 unscrew the check valve 14th to review or exchange.

finally shows a third state of the safety valve group 10 , in which the ball lock 15 ' of the downstream second shut-off valve 15th by 90 ° in a direction opposite to the previous one in the direction of the arrow W2 from is rotated to check and / or replace the safety valve 17th to enable; in this case is the safety valve group 10 closed both to the water supply network I and to the storage tank SA.

This can be achieved by removing the screw 30th with a special tool is unscrewed to the control handle 15E easy to pull out until the teeth 27 , 28 and 29 are resolved; then the control handle 15E be rotated, with the position of the two teeth 27 and 28 with regard to the locking tooth 29 is reversed, causing the ball lock 15 ' can turn to the optional third position.

The safety valve group is in this state 10 both to the exit 12 as well as to the storage tank SA shut off to the safety valve 17th to be checked or to be replaced with another suitable valve. Once the review or replacement of the safety valve 17th is complete, the control handle can 15E returned to its old position and again on the axis of rotation 22B of the second shut-off valve 15th be fastened, taking the screw 30th operated with the special tool.

Figures 2 to 6 show a preferred first solution of the safety valve group according to the invention 10 whose main feature is the use of a special three-way valve on the downstream side, which can be operated in either two working positions, always with a connection to the safety valve 17th to the exit 12 the safety valve group 10 or to the check valve 14th via the branched passages 25th , 26th of the ball lock 15 ' preserved.

Another feature of the solution by to consists in the aligned arrangement of the two shut-off valves 13 , 15th and the check valve 14th and in the presence of the curved section 19th of the flow path in which one through the plug 20th closed inspection opening is provided to ensure the tightness of the check valve 14th to check; this particular geometric configuration of the safety valve group 10 in combination with the arrangement of the valves in a line and with an arrangement of the safety valve 17th coaxial with the second shut-off valve 15th on the downstream side has the creation of a very compact safety valve group 10 allows, which has a comparatively small footprint and is less expensive compared to the previously known safety valve groups, the main property, a check and / or control of the safety valve 17th against overpressure without danger for an operator authorized to do this work is maintained.

A second preferred solution is in using the same reference numbers from the previous figures to denote similar or equivalent parts and the safety valve assembly 10 with both shut-off valves 13 , 15th is mounted in the open state.

The solution from differs from the previous one in removing the bent section 19th and by a different orientation of the check valve 14th and by replacing the first shut-off valve designed as a two-way ball valve 13 by a shut-off valve 13 * designed as a three-way ball valve on the side of the inlet 11 the safety valve group 10 axially to one through a removable plug 33 closed access opening 32 is aligned to the tightness of the check valve 14th check, for example in the previous figures.

While in the case of to the check valve 14th even though it was with the two shut-off valves 13 and 15th of the group is aligned along the longitudinal flow path, on one side of the curved section 19th with its axis at right angles to the longitudinal axis of the safety valve group 10 was positioned, the check valve has 14th in case of more precisely its axis coaxial with the safety valve group 10 positioned immediately after the first shut-off valve 13 *; also in this case the check valve 14th can be removed and replaced through a side opening, which is through the main plug 23 and a blocking system to prevent the ball lock of the check valve from slipping out 14th is closed, which in turn with a by a plug 21st closed opening is provided.

As mentioned above, the two shut-off valves 13 * and 15 designed as three-way valves are from FIG completely identical and therefore the same reference numbers have been used to refer to similar or equivalent parts; the difference between the two shut-off valves 13 * and 15 in consists in the fact that the ball lock 15 ' of the second shut-off valve 13 * has only two operative positions, one fully open to both the entrance 11 as well as the check valve 14th that in is shown, the other with the ball lock rotated by 90 ° 15 ' when closed to the side of the entrance 11 the safety valve group 10 down, the two branched passages 25th , 26th and the corresponding openings 15C and 15D to the access opening 32 or to the check valve 14th stay directed. Otherwise, the functionality of the safety valve group 10 in completely identical to that of the safety valve group 10 from as described earlier.

From the foregoing description and from the representations in the accompanying drawings, it is therefore clear that the invention relates to a safety valve assembly which is suitable for achieving the aforementioned objects and advantages, in which ball shut-off valves are fitted to the inlet and outlet side and a check valve in between, in which the shut-off valve on the outlet side or after the safety valve group consists of a special three-way ball valve which is provided with a closure, which is formed with a main passage and two branched passages, which are suitable to maintain a connection with a safety valve against overpressure on the outlet side in each of the three angular positions of the same closure.

Further features of the safety valve group in combination with the preceding ones consist in the presence of a curved section with a corresponding access opening between the shut-off valve on the inlet side or upstream side and the check valve and in the orientation of the check valve at right angles to the longitudinal axis of the safety valve group according to a first solution; they also consist of the use of a three-way ball valve on the upstream or input side, similar to the three-way valve on the output or downstream side; and finally in the aligned arrangement of the inspection opening with the three-way valve on the inlet side and in the arrangement of the check valve with the axis aligned with the longitudinal axis of the group according to a second solution.

In all cases, a safety valve group with better functionality is produced, the structure and dimensions of which are extremely compact compared to the known valve groups.

It is understood, however, that what has been described and shown in the accompanying drawings is intended to illustrate the innovative features of the safety valve assembly 10 and some preferred embodiments; therefore, further changes can be made to the entire safety valve group 10 or parts thereof can be attached without thereby exceeding the claims.

Claims (9)

A safety valve assembly (10) comprising: a body defining a flow path between an inlet (11) and an outlet (12) for a liquid aligned along a longitudinal axis; a first shut-off valve (13, 13 *) for the liquid at the level of the side of the inlet (11); and a second shut-off valve (15) on the side of the outlet (12); a check valve (14) between the first and second shut-off valves (13, 13 *, 15); and a safety valve (17) against excess pressure at the level of the outlet (12) of the safety valve group (10); the safety valve group (10) being provided with at least one inspection opening for the check valve (14) which is closed by a removable plug (20), the first and second shut-off valves (13, 13 *, 15) and the check valve (14) are aligned along the longitudinal axis of the safety valve group (10); wherein the second shut-off valve (15) is a three-way ball valve which comprises an auxiliary outlet (16) for the safety valve (17); and wherein the second shut-off valve (15) has a ball lock (15 ') which is formed with a main passage (24) and two branched passages (25, 26), the ball lock (15') of the second shut-off valve (15) optionally in two operative positions and can be brought into an optional third position, whereby: it connects the outlet (12) with the inlet (11) of the safety valve group (10) via the main passage (24) and the main passage (24) in a first operative position connects to the auxiliary outlet (16) for the safety valve (17) via a first branched passage (25); in a second operative position it connects the outlet (12) of the safety valve group (10) to the auxiliary outlet (16) for the safety valve (17) via the two branched passages (25, 26) and closes it towards the check valve (14); while in the optional third position it closes towards the outlet (12) of the safety valve group (10) and maintains a connection between the safety valve (17) and the check valve (14) via the branched passages (25, 26). Safety valve group (10) loud Claim 1 characterized in that it comprises a first inspection opening closed by a removable plug (20) at the level of a curved section (19) of the safety valve group (10) between the first shut-off valve (13) and the check valve (14). Safety valve group (10) loud Claim 1 or 2 , characterized in that it comprises a second viewing port, closed by a removable plug (21), axially aligned and under the check valve (14). Safety valve group (10) loud Claim 3 characterized in that the second viewing port is provided in a removable main plug (23) adapted to permit removal of the check valve (14). Safety valve assembly (10) according to any one of the preceding claims, characterized in that the ball closures (13 ', 15') of the first and second shut-off valves (13, 15) are connected to respective control handles (13E, 15E) which are located on the the safety valve group (10) opposite to that of the bent portion (19) and the safety valve (17). Safety valve group (10) loud Claim 1 , characterized in that the axis of the safety valve (17) is aligned at right angles to the longitudinal axis of the safety valve group (10) and is positioned on the axis of rotation (22B) of the ball lock (15 ') of the second shut-off valve (15). Safety valve group (10) loud Claim 1 , characterized in that the first shut-off valve (13 *) on the side of the inlet (11) is a three-way valve, which is designed like the second shut-off valve (15) on the side of the outlet (12) of the safety valve group (10). Safety valve group (10) loud Claim 7 , characterized in that it comprises an access opening (32) for the check valve (14) which is axially aligned with an outlet of the first shut-off valve (13 *) on the side of the inlet (11) of the safety valve group (10). Safety valve group (10) loud Claim 8 , characterized in that the axis of the check valve (14) is aligned parallel to the longitudinal axis of the safety valve group (10).

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