FR2537885A1 - DEVICE FOR THE MECHANICAL PURIFICATION OF A COOLING WATER FLOW OF CONDENSERS OF POWER PLANTS - Google Patents

Abstract

DEVICE FOR THE MECHANICAL PURIFICATION OF A CURRENT OF COOLING WATER FROM POWER PLANT CONDENSERS, INCLUDING A CYLINDRICAL SIEVE HOLDER, A SCREENING DEVICE FOR SIEVING IMPURITIES IN THE SIEVE HOLDER AND A WASHING DEVICE -CURRENT. THE SCREENING DEVICE CONTAINS A PLURALITY OF SCREENING SURFACES ARRANGED OBLIQUE WITH RESPECT TO THE DIRECTION OF CURRENT. BACK-CURRENT WASHING IS DONE BY A PARTIAL CURRENT OF COOLING WATER. SEEN IN THE DIRECTION OF THE COOLING WATER CURRENT, THE SIEVE HOLDER HOUSING IS DIVIDED INTO AT LEAST TWO SECTORAL CHAMBERS TO WHICH ARE CONNECTED, IN THE DIRECTION OF THE CURRENT, UPSTREAM OF THE SCREENING SYSTEM, TUBING 6 FOR THE DRAINING OF WATER USEES EQUIPPED WITH A WASTE WATER VALVE 5. FOR BACK-CURRENT WASHING OF A SCREENING SURFACE 4 ASSOCIATED WITH A SECTORAL CHAMBER SK OR SCREENING SURFACES ASSOCIATED WITH A SECTORAL CHAMBER, THE DIFFERENT SECTOR CHAMBERS CAN BE CLOSED TO THE FLOW OF COOLING WATER BELOW THE DRAIN TUBING USING A SHUT-OFF VALVE 7, WHEREAS, IN SUCH A BACKWASH, THE CORRESPONDING WASTE WATER VALVE 5 DISCHARGE TUBING 6 IS OPEN.

Description

i The invention relates to a device for purification.

  mechanics of a condensing cooling water stream

  power plant screen holders, comprising a housing /, a screening device for removing impurities in the screen housing and a backwashing device, the screening device comprising a plurality of screening surfaces arranged obliquely to the direction of the current which can be washed against the current by a backwashing device,

  namely using a partial stream of cooling water

  while also maintaining the purifying function.

  cooling water ration; the counter-current washing device having, in addition, a device for the evacuation of waste water allowing the evacuation of the back-washing water charged with the removed impurities. The formulation according to which the sieving device comprises a plurality of sieving surface

  does not exclude the fact that these sieving surfaces constitute

  as for construction, they kill a whole and they

  are separated or separable only on the functional level-

  nel. In the well-known system of this kind (Hawker Siddeley Brackett Ltd prospectus, Ref No 2010, page 3), the sieve basket is, as a first approximation, a cylindrical or frustoconical basket whose wall is somewhat wavy in accordion. troughs of the waves extend almost parallel to the axis of the sieve basket The sides of the crests -or the troughs

  waves form the different sieving surfaces.

  The backwashing device consists of a backwashing tank to which the waste water outlet tubing is connected. The backwashing tank can be swiveled with the water backwater tubing worn around the axis of the sieving device thus formed in such a way that, during this pivoting, the sieving surfaces of this device can be successively cleaned by suction This measurement requires a significant expense for the drive

  and the command and its effect is often not satisfactory.

  Furthermore, it requires a screen housing which is arranged orthogonally to the axis of the supply and discharge pipe for the cooling water stream. The screen basket whose wall is open on the inlet side is arranged so analogous The screen housing has a diameter which is appreciably larger than that of the pipe for the supply and the evacuation of the cooling water current.

  The present invention aims to improve

  ner a system of the aforementioned kind in such a way that backwashing can be carried out in a simple manner, without aspiration by a movable waste water discharge pipe which in a way explores the device for

  sieving, and that the control can be carried out via the

  simple valves and valves insensitive to fouling. According to the invention, this object is achieved by the fact that the sump carrier is divided, in the direction of flow of the cooling water, into at least two sectoral chambers to which is connected, seen in the direction of flow upstream of the screening device, a

  waste water evacuation pipe fitted with a

  pope, that, for backwashing the sieving surface or the sieving surfaces associated with a sectoral chamber, the various sectoral chambers can be closed with the flow of cooling water below the discharge pipe waste water by means of a shut-off valve that, in addition, the corresponding valve of the waste water discharge pipe is opened during such a backwashing Depending on the pressure conditions, the waste water can be aspirated or simply evacuated through the evacuation pipe In the simplest case, the screen holder housing is divided into two chambers

  with a semi-circular horizontal plane.

  A preferred embodiment of the invention which is

  toke by the fact that, during backwashing, the system pressure drop varies only a little overall, is characterized in that the screen housing has four sectoral chambers with a horizontal plane of one quarter-circle with which two quarter-circle check valves are associated in pairs and said stop valves can be pivoted about a common axis It is then perfectly possible to successively control the backwash in the different dry rooms

  quarter-circle torelles since the rear valves

  quarter-circle rêt are attached to a common shaft with a respective offset of 90 But it is also possible to provide two autonomous shafts provided they are arranged coaxially and engaged on different sides in the

screen holder housing.

  The simplicity of construction and maintenance

  characterizes an embodiment in which each cham-

  sectoral bre has a separate tubing for the evacuation

  tion of wastewater with valve which is engaged in the wall of the screen holder casing and oriented essentially radially Another embodiment of the invention

  which is distinguished by a compact construction is characterized

  laughed at the fact that the sectoral chambers are equipped

  a single waste water discharge pipe which

  mouth in the center of the screen holder casing and which is brought out via an elbow, and that the various sectoral chambers can be connected alternately, by their outlet valve, to the tubing

waste water disposal.

  the In / system according to the invention; the shut-off valve or the shut-off valves on the one hand and the wastewater valves on the other hand can be controlled independently of each other This is possible without difficulty

  using auxiliary means of the training technique

  modern and control A simplification can be obtained from the fact that the movement of the shut-off valve associated with a sectoral chamber and the actuation of the valve

  of wastewater associated with a sectoral chamber are covered

  plés This coupling can be a coupling at the level of the control technique and therefore an electrotechnical coupling

  or hydraulic through the different drives-

  However, it is also possible to carry out a mechanical coupling and to arrange the system in such a way that, from the construction point of view, the shut-off valve and the waste water valve of each sectoral chamber are combined in a homogeneous group and that the pipes for the 1. evacuation of waste water in the different sectoral chambers or the common evacuation pipe of -all the sectoral chambers are arranged in such a way that, when one of the sectoral chambers is blocked , the corresponding evacuation pipe is open and vice versa. In principle, in the system according to the invention, the shape of the screening surfaces can be chosen in any way. However, it is recommended to arrange the screening surfaces so that the current

  which is established or which can be carried out by vacuum

  tion in a system according to the invention allows to easily and easily remove the impurities retained on the sieving surface For this purpose, the invention provides, in combination with the measures described above, that the sieving surfaces are assembled into a pleated with ridges and at least one hollow and that, in the direction of the current, the hollow (s) are disposed immediately above the transverse section plane occupied by the associated shut-off valve in the closed position At in particular, it is possible to assemble the sieving surfaces from a plurality of cone trunks which, with the cone angle oriented in opposite directions, are nested concentrically one inside the other and joined by their edges For this embodiment, the invention also provides for choosing an extremely small cone angle and therefore for inserting frustoconical surfaces which

  practically have a cylindrical shape It is also

  In the context of the invention, it is possible to choose as a sieve surface a single cone trunk whose angle

  at the top can be large or small According to another characteristic

  In accordance with the invention, the sieving surfaces with ridges and hollows which extend radially, in a manner in the form of spokes, are arranged around the axis of the sieve holder housing. However, the sieving surface can also be arranged in the various sectoral chambers with ridges and hollows which extend tangentially to concentric circles in the screen holder casing In any case, it is recommended to choose a

  arrangement such that, in the direction of the axis of the car-

  ter screen holder, the screening surfaces have an extension which corresponds roughly to the radius of the screen holder housing A system according to the invention can be designed without difficulty in such a way that the diameter of the screen holder housing is not no bigger than driving

  for supplying or discharging the cooling water stream

  In this case, backwashing acts uni-

  formally over the entire sieving surface.

  The following description, next to the drawings

  appended by way of nonlimiting examples, will make it possible to understand clearly how the invention can be put into practice. Figure 1 shows a longitudinal section of the

  simplest embodiment of the invention.

  Figure 2 shows a section along the line

A-A of the object of figure 1.

  Figures 3 a to 3 d show, in section according to Figure 2, another embodiment of the system according

  the invention and illustrate various operating positions.

  Figure 4 shows, in perspective, the valve

  stopping the object of Figures 3 a to 3 d.

  Figure 5 shows a longitudinal section

  of a sieving device of a system according to the invention.

  Figure 6 shows another embodiment

of the object of figure 5.

  Figure 7 shows an axial section of another

  embodiment of the system according to the invention.

  Figure 8 shows a section along the line

B-B of the object of figure 7.

  FIG. 9 shows, in perspective and with partial cutaway, another embodiment of a

device according to the invention.

  The device shown is intended for the mechanical purification of a stream of cooling water from

  power plant condensers It includes basic

  a cylindrical screen holder housing 1, a device

  2 and a backwashing device 3.

  The screening device 2 has a plurality of screening surfaces 4 arranged obliquely to the flow direction and which can also be

  interconnected The backwashing device

  stream 3 allows the screening surfaces 4 to be washed by means of a partial stream of cooling water, and

  this while also maintaining the purification function.

  The backwash then always acts on 4 different sieving surfaces. The 3 l backwash device has a waste water evacuation system by which / backwash loaded.

  impurities can be removed.

  Figures 1 and 2 illustrate the basic principle

  tal of a device according to the invention It is noted that the housing p Qrtetamis 1, seen in the direction of flow of the cooling water, is divided into two sectoral chambers SK In the direction of flow, the sectoral chambers SK are connected, upstream of the screening device 2, to a waste water evacuation pipe 6 provided with a waste water valve 5 For backwashing of a screening surface 4 or screening surfaces 4 associated with a sectoral chamber SK, the various sectoral chambers SK can be closed with a stream of cooling water, below the discharge pipe 6, by means of a shut-off valve 7 The figure

  1 indicates such a closed position, the rear valve

  rêt 7 having been brought, on the right, in the high position.

  The pivot axis 8 of the stop valve 7 defines in

  sort of the separation of sectoral chambers SK.

  It goes without saying that it is also possible to mount a corresponding separation plate and to have the stop valve 7 in a lower position in the embodiment according to FIG. 1, during such a backwashing. current, the corresponding wastewater valve 5 of the discharge pipe 6 is open. In a way, hydrodynamic conditions are obtained automatically, the effect of which is the evacuation of impurities which, during

  normal purification, are somehow accumulated

  below the sieving surface 4.

  It is clear from the suggested embodiment-

  re in Figures 3 a to 3 d and 4 that the screen holder housing i

  presents, on the horizontal plane, four sectoral chambers-

  the quarter-circle SKs with which two quarter-circle check valves are associated in pairs 7 The quarter-circle check valves 7 can rotate around a common pivot axis 8 In the embodiment according to

  Figures 3 a to 3 d and 4, the two quarter-of-stop valves

  circle 7 have a common shaft 8 which defines the pivot axis But it is also possible to divide the shaft 8 in order to be able to move the two quarter-circle check valves 7 not only together but also one relative to the other The embodiment shown in which the quarter-circle check valves 7 are mounted with an offset of 900 on a common shaft 8 is

however simpler.

  In the exemplary embodiment according to FIGS. 1 to 6, the arrangement chosen is such that each room

  sectoral SK has a drainage pipe '6 separate

  line engaged in the wall of the screen holder casing i 1 from which it extends essentially radially The same is true for the embodiment according to FIG. 9 The conformation is different for the embodiment according to FIGS. 7 and 8 o the sectoral chambers SK comprise a single common tubing 6 for the evacuation of waste water which opens out at the center of the screen holder casing 1 and which is brought towards the outside via an elbow 9, The different sectoral chambers SK can be connected alternately to the discharge pipe 6 via their waste water valve 5,

  , It goes without saying that in the devices according to the

  vention, the movement of the shut-off valve 7 associated with one of the sectoral chambers SK will be coupled to the actuation of the wastewater valve 5 associated with one of the sectoral chambers SK In particular, it is possible to bring together the shut-off valve 7 as well as the waste water valve 5 of each sectoral chamber SK in a homogeneous whole. This is apparent from FIGS. 7 and 8 where the waste water valves 5 have become, so to speak, valves which open or close. the corresponding inlet ports for the tubu-

  waste water evacuation lure 6 The evacuation pipes

  tion 6 in the different sectoral chambers SK or the evacuation pipe 6 common to all the sectoral chambers SK are arranged in such a way that during the

  closing of a sectoral chamber SK the evacuation pipe

  corresponding 6 is open, and vice versa.

  In the devices according to the invention shown in the drawings, the sieving surfaces 4 are assembled - in a pleat with ridges 10 and with at least one recess 11 The assembly is carried out in such a way that the recess (s) are located immediately above the transverse section plane occupied by the associated shut-off valve 7 in the closed position It is clearly seen from FIGS. 5 and 6 that the screen surfaces 4 can be simply assembled from a plurality of trunks of cones which are concentrically fitted into each other, the cone angle being respectively oriented in an opposite direction, and which are joined by

  the edges of the trunks of cone 12 But the sieve surfaces

  sage 4 could also have ridges 10 and recesses il radially oriented and be suitably arranged around the axis of the screen holder casing 1, which has not, however, been shown in the drawings FIG. 9 shows that the sieving surfaces 4 can be arranged in such a way that the ridges 10 and the hollows 11 tangent circles inside the screen holder casing 1 Their extension in the axial direction roughly corresponds

  within the radius of said screen holder housing 1.

Claims (10)

  1 Device for the mechanical purification of a cooling water stream from condensers of electric power stations, comprising a cylindrical screen holder housing, a screening device for removing impurities in the screen holder housing and a backwashing, the sieving device comprising a plurality of sieving surfaces arranged obliquely by   flow direction which can be washed against   current by a backwashing device,   know using a partial stream of cooling water   while maintaining the purifying function of the cooling water; the backwashing device having, in addition, a device for the evacuation of waste water allowing the evacuation of the backwashing water loaded with the removed impurities, characterized in that the casing carries sieve (1) is divided, in the direction of flow of the cooling water, into at least two sectoral chambers   (SK) to which is connected, seen in the flow direction-   upstream of the sieving device, a pipe (6) for the evacuation of waste water provided with a water valve   worn (5), that for backwashing the over-   sieving face (4) or sieving surfaces (4) associated with one of the sectoral chambers (SK), the various sectoral chambers can be closed with the flow of cooling water below the water evacuation pipe waste (6) by means of a shut-off valve (7) and that, in addition, the corresponding valve (5) of the waste water outlet pipe (6) is opened when of such a backwash.   2 Device according to claim 1, characterized in that the screen holder casing has four sectoral chambers with a horizontal plane of a quarter circle with which are associated in pairs two quarter circle check valves (7) and that said check valves   (7) can be pivoted about a common axis (8).   3 Device according to claim 2, characterized in that the quarter-circle check valves (7) are attached to a common shaft (8) with a respective offset of 90.   4 Device according to one of claims 1 to   3, characterized in that each sectoral chamber (SK) comprises a waste water discharge pipe (6) separated by a valve (5) which is mounted in the wall of the   screen holder housing (1) and oriented essentially radial- is lying.   Device according to one of claims 1 to   3, characterized in that the sectoral chambers (SK) are provided with a single waste water discharge pipe (6) which opens out at the center of the screen holder casing (1) and which is brought outwards by through an elbow (9), and that the various sectoral chambers (SK) can be connected alternately, by their outlet valve (5), to the water evacuation pipe worn (6).   6 Device according to one of claims 1 to   , characterized in that the movement of the rear valve   rêt (7) associated with a sectoral chamber (SK) and the action-   sewage valve (5) associated with a   sectoral chamber (SK) are coupled.   7 Device according to claim 6, character-   se by the fact that the shut-off valve (7) as well as the waste water valve (5) of each sectoral chamber (SK) are united in a homogeneous group and that the pipes   waste water outlet (6) in the various rooms   sectoral bres (SK) or the evacuation pipe (6)   of all the sectoral chambers (SK) are available   so that when one of the rooms is blocked   sectoral (SK), the evacuation pipe (6) corresponds dante is open and vice versa.   8 Device according to one of claims 1 to   7, characterized in that, in combination with the measures described above, the sieving surfaces (4) are assembled in a pleat with ridges (10) and at least one hollow (11) and that, in the direction current, the recess (s) (11) are arranged immediately above the transverse section plane occupied by the shut-off valve (7) ll   associated in the closed position.   9 Device according to claim 8, character-   se by the fact that the screening surfaces (4) are assembled from a plurality of truncated cones which, with the cone angle oriented in opposite directions, are nested concentrically in each other and joined by their edges (12).   Device according to claim 8, character-   laughed at by the fact that the screening surfaces (4) are arranged around the axis of the screen housing (1), the   ridges (10) and the recesses (11) extending radially.   11 Device according to claim 8, character-   laughed at by the fact that the screening surfaces (4) are arranged in the sectoral chambers (SK) with   ridges (10) and valleys (11) which extend tangentially-   in concentric circles in the screen housing (1).   12 Device according to one of claims 8 to   11, characterized in that, in the direction of the axis of the screen holder housing (1), the screening surfaces (4) have an extension which roughly corresponds to the   radius of said screen holder housing (1).