FR2628459A1 - VACUUM WASTEWATER EXHAUST SYSTEM - Google Patents

Abstract

A collector 42 receives wastewater from water closet 43 equipped with flushes and vacuum valves. These water and air are sucked into it by a liquid ring pump P which delivers them to the sewer 44. The liquid ring is maintained by clear water arriving via a supply pipe 45. The invention applies to on-board or on-land sanitation networks.

Description

System vauaio or vd- 1 wastewater Vacuum evacuation system

  Sewage systems are known Sewage evacuation systems have been known for a long time. Such waters often contain

  not very resistant. They come in particular from water closet bowls.

  They circulate in vacuum evacuation conduits in the form of packets that occupy the entire section of the duct and which are why called plugs. These plugs are followed by

  air masses that ensure their propulsion.

  Compared to a gravity evacuation, the evacuation under vacuum has three essential advantages: - the diameters of the ducts required for evacuation under vacuum are much smaller than the diameters necessary for gravity evacuation, - unlike gravity evacuation, Vacuum evacuation works regardless of the slope of the ducts. In particular, it allows the flow to be traced up to a maximum height corresponding to the value of the depression expressed in meters of water column, - the evacuation of the water-closet requires only a small flush volume: less 1.5 liters of water, compared to 6 to 9 liters

  for gravity evacuation systems.

  These advantages are particularly interesting for evacuation

  water closets in surface or underwater vessels

  sailors. Various techniques are known for generating the vacuum: A first known technique consists in collecting the wastewater in a tank which is evacuated by means of a vacuum pump. This pump only has the function of creating and maintaining the vacuum in the installation. It sucks only air. For

  able to empty the tank without interrupting the function

  In addition to the installation, it is necessary to have another pump that can suck the materials under vacuum, or to provide sophisticated airlock systems. Moreover, the wastewater being stored under vacuum,

  aerobic degradation of materials does not occur.

  - To overcome these disadvantages, a second technique is known from French Patent No. 82 04710. It consists in completing the installation with vacuum pump by a barometric column which allows

Z2628459

  Transfer of the wastewater continuously from the vacuum network to a collector at atmospheric pressure. The storage tank is no longer essential. The major disadvantage of this technique is to require a large height (5 to 10 m) between the collector and the low point of the vacuum network. - A third known technique is. described in French Patent No. 2,308,742 and its US correspondent No. 4,034,421. According to this technique, a storage tank is used at atmospheric pressure. A circulation pump draws the sewage stored in this tank, and presses it under pressure into an ejector whose diverging returns them to the tank. The neck of the ejector is connected to the evacuation network in which it maintains the vacuum. Wastewater, air and materials are transferred

  from the vacuum network to the tank via the ejector.

  This technique has the advantage of leaving the storage tank

  at atmospheric pressure without major complication of the

  tion. However, it has the disadvantage of the ejectors which is a poor performance, which results in an over-power of the circulation pump, or by the multiplication of groups

eductor / pump.

  Finally, a fourth known technique consists in using an Archimedean screw vacuum pump to create and maintain the vacuum

  in a tank connected to the wastewater collection network.

  A special screw pump capable of aspirating liquids and gases has been developed for this application. This pump is not

  however not able to transit the solids.

  The tank must therefore be equipped to sort the materials and

  grind. The installation becomes much more complex.

  The present invention particularly aims the simple realization of a vacuum evacuation system of wastewater. It also aims that this system is robust, energy efficient and directly connectable, with or without storage tank, to a collector at atmospheric pressure, without

  barometric column height constraint.

  In general, a system according to the invention comprises the following elements which are common, at least as regards certain of their purposes for this system and to a known system produced according to the third known technique previously mentioned: a tubular collector for receiving said wastewater in the form of successive plugs, as well as subsequent air masses.

  to these plugs and coming from the atmosphere, -

  and circulation, suction and discharge means connected to this manifold for sucking up these plugs and these consecutive air masses by lowering the air pressure in said manifold to a suction pressure lower than the atmospheric pressure, and to push back said wastewater under a discharge pressure greater than said suction pressure and sufficient to allow their evacuation. In this known system, said circulation, suction and discharge means comprise in particular said circulation pump and said ejector, the latter to constitute suction means

and repression.

  With respect to this known system, the system according to the invention is characterized in that said suction and discharge circulation means comprise - a liquid ring pump provided with a suction passage connected to said manifold, a passage discharge pipe for discharging said waste water, and a water supply passage for receiving a minority flow of a feed water clean to form and / or maintain a liquid ring in this pump,

  and water supply means for supplying said feed water

  tation. According to the invention, it is also possible to adopt, if the circumstances lend themselves to it, the following preferred arrangements: As in said known system, said circulation, suction and discharge means furthermore comprise a tank receiving and temporarily containing said wastewater. under a storage pressure greater than said suction pressure. In the system according to the invention, said tank is connected to said passage

  delivery of said liquid ring pump.

  - A supply pipe connects a lower portion of said tank - 4 - said suction passage of said liquid ring pump so as to suck a minority flow of waste water from the reservoir to maintain said liquid ring, said means providing clear water and being controllable so that they can stop supplying this clear water when this

  Ring can be serviced by this waste water.

  - The system further comprises valves and pipe to allow, after a period of storage of said wastewater in said tank, which then constitutes a storage tank, to drain the tank under the action of suction and discharge

of said liquid ring pump.

  Said valves and ducting for enabling said storage tank to be emptied comprise an air introduction valve which, when it is open, makes said suction passage of said liquid ring pump communicate with the atmosphere; a valve which, when closed, eliminates the connection of this suction passage to said manifold, - and a drain line connecting a lower portion of said storage tank to an evacuation zone so that, in a period of storage during which the air introduction valve is closed and this separation valve open, this pump sucks said plugs and said consecutive air masses and discharges said waste water into said tank to store the waste water, and so . that, in a period of emptying during which this air introduction valve is open and this separation valve closed, this same pump sucks a flow of air from the atmosphere and forces this flow of air into said storage tank under a discharge pressure which constitutes said discharge pressure and which is greater than the atmospheric pressure and said storage pressure, whereby this discharge air flow itself flows through said drain pipe , wastewater that has been stored in this tank

  during a said previous storage period.

  Said storage tank is provided with a ventilation valve which is located at the top and which is closed during said emptying period, and with a drain valve which is situated on said drain pipe and which is open during this emptying period. Said collector is connected to said suction passage of said liquid ring pump via a heavy particle trap. The invention applies in particular to the case where the wastewater contains organic materials whose pollutant power can be reduced.

  by continued aeration for a suitable aeration time.

  In this case, said tank is a storage tank for storing said waste water during said aeration time, and said discharge passage communicates with this tank via a discharge pipe opening at the bottom of this tank, in such a way that the air discharged by this pump rises in the form of bubbles through the thickness of the sewage stored in this reservoir. As known pumps, said liquid ring pump comprises a pump body having a generally cylindrical peripheral wall around a shaft axis, - a rotor provided with blades, having a rotor axis and rotating in this body about this axis, the latter being offset with respect to said body axis, - a motor for driving this rotor, - a distributor constituting a wall in contact with the internal space at said pump body, - a suction port and a discharge port pierced in this distributor, - and a pass feeding age for introducing water into said body so that the water thus introduced constitutes a liquid ring rotated by said rotor blades and pressed by the centrifugal force against said peripheral wall and that chambers of These rotating blades are formed by these blades and ring and suck a fluid to be pumped through said suction lumen and discharge it through said discharge lumen. According to the invention, said suction lumen is sufficiently wide to contain a circle with a diameter of about 40 mm, so as to facilitate the suction of weak materials that may be part of said plugs. As known pumps, said liquid ring pump is further provided with tubular suction and discharge passages.

  connected respectively to said suction and discharge ports

  each with an axis. According to the invention said axis of said suction passage and preferably that of said discharge passage are substantially parallel to said body and rotor axes and their extensions pass substantially through

  said suction and discharge ports, respectively.

  With the aid of the schematic figures, attached, will be described more particularly below, by way of non-limiting example, how the present invention can be implemented within the framework of the presentation that has been given above. When the same element is represented in several figures, it is designated by the same reference sign. It should be understood that the elements mentioned can be replaced by other elements ensuring

the same technical functions.

  FIG. 1 represents an exploded perspective view of a

known liquid ring pump.

  FIG. 2 represents a sectional view of the body of this

pump in operation.

  FIG. 3 represents a view of the dispenser of a modified liquid ring pump according to the invention, the drawing of suction and delivery ports of the dispenser of said pump.

  known being shown in dotted line.

  FIG. 4 represents an end view of said modified pump, the suction and discharge passages of said

  known pump being shown in dotted line.

  Figures 5, 6 and 7 show overviews of a

  first, second and third systems according to the invention.

  The principle of the liquid ring pump has been known for a long time for pumping gas, especially for evacuating an enclosure. It is for example described a liquid ring pump known for this purpose and shown in Fig.1 comprises a rotor 11 provided with blades 11A and driven by an electric motor 10. This rotor rotates in a pump body 12 around a 11B axis parallel to the axis 12A of this body. The gas to be pumped enters through a suction flange 13 of a flange 14. It then passes into the pump body through a suction port 15 of a distributor 16 (see FIG.

  fig.3). The compressed gas is finally discharged by a refueling light.

  17 of the distributor and discharged by a discharge flange of the flange. A liquid ring 92 (see FIG. 2) is constituted by water which has been introduced in a suitable volume into the body 12 and driven in rotation by the rotor 11. It is pressed by the centrifugal force against the cylindrical wall of this body and leash

  a free axial volume for suction and compression of the gas.

  It constitutes for the gas a seal between the rotor blades and the wall of the pump body. Two successive blades and the liquid ring define a rotating chamber whose volume is large when it passes next to the suction light 15

  and small compared to the light of repression 17.

  The calories produced by gas compression and friction are absorbed by the water of the liquid ring, which must be renewed to avoid excessive heating. This is why a supply of water to the liquid ring is carried out permanently by means of an orifice 19 of the flange, the water then entering the pump body through a supply port 100 of the distributor. This excess of water thickens the ring radially

  liquid which continuously pours the surplus through the refueling light.

  The known advantages of this type of pump are that it is robust and not very sensitive to the presence of liquids or dusts.

driven by the pumped gas.

  According to the invention a similar pump is used to suck and discharge a water-based mass. It appeared that this pump -8- was suitable for the transit of soft materials which, penetrating into the pump body by the suction port 15, are minced by the blades of the rotor 11. The grinding is made possible by the robustness rotor that equips this type of pumps. In order to facilitate the transit of the materials and to prevent clogging of the pump, this is adapted as follows: 1) The suction and discharge ports 17 of the known distributor 16 are replaced by enlarged lights 21 and 22 as

  shown in Figure 3. The object of this enlargement is mainly

  avoid an object that could have entered the network

  under vacuum can become blocked at the inlet of the suction lumen.

  That is why this light is enlarged until it can contain at least one circle whose diameter is the inside diameter

  -the connecting pipe of the water-closets, about 40 mm.

  2) To prevent clogging of the ducts defined by the flange 14 and the distributor 16, the suction flanges 13 and discharge 18 are replaced by suction flanges 33 and discharge 34 having larger diameter orifices drilled on

  the flat face of the flange 14, so that their axes are parallel

  11B of the rotor and 12A of the pump body, and that they intersect the suction and discharge ports 21 and

  22 where they were enlarged.

  Figure 5 shows a first system in which the liquid ring pump is connected to a wastewater collection system. This network is shown schematically by a manifold 42 which is connected to a water closet bowl provided with a flush and a vacuum-evacuation valve. This hunt

  and this valve are of known types and are not shown.

  The suction flange 33 is connected to the collection network.

  The discharge flange 34 is connected via the pipe 41 directly to the vent pipe or sewer 44 which is at atmospheric pressure. The operation of the liquid ring pump requires a low flow water supply, intended for

  to maintain the volume of the liquid ring and to ensure the cooling

  ment. This feed arrives at the supply port - 9 - 19 of the pump by means of the conduit 45, the flow being regulated by

the valve 46.

  In the system which has just been described, the liquid ring pump transfers gases, water and solids from the vacuum network to the sewer 44 at atmospheric pressure, as well as the grinding of these solids. The advantages of the invention appear clearly since on the one hand a single rotating machine is sufficient to ensure the triple function of vacuum pump, water pump, and grinder, on the other hand the storage tank is not essential and that finally the electric power installed and consumed is much lower than the power

  required for an installation with ejectors with the same suction capacity

  tion. According to a preferred arrangement also shown in Figure 5, a trap is placed upstream of the liquid ring pump to retain very heavy particles, such as metal objects, which could have been introduced, by accident or malice, in the wastewater collection facility and that could damage the liquid ring pump. This trap can be constituted by a simple box 51 through which wastewater passes, the inlet / outlet ports 52 and 53 being placed at the upper part of the box so that the heavy objects fall to the bottom of the box and do not reach the pump. The fund can be emptied periodically by means of

a trap door 54.

  According to another preferred arrangement also shown in Figure 5, it is useful to set up between the vacuum network and the liquid ring pump a non-return valve 55, and upstream of the valve a vacuum switch 56 capable, by through a relay 57, start the pump on a high pressure threshold and stop it at a low pressure threshold. Thus, when the sanitary installation is only little or not used, the liquid ring pump stops when the low pressure threshold is reached, and the valve closes thus isolating the installation

  under vacuum. Depending on the frequency of use of the

- 10 -

  the void breaks up little by little. The pump then re-engages on the high pressure threshold and discharges the water and the materials

accumulated in the pipes.

  A disadvantage of the first system which has just been described according to the invention is the need to supply the liquid ring with clear water, which penalizes the water consumption of the entire installation. To overcome this drawback, it is preferable to introduce, between the pump and the exhaust manifold of a second system according to the invention, a storage tank 61 as indicated in FIG. an air vent 62 and a drain pipe 63 closed by a valve 64. The tank is emptied either periodically or continuously, by any means not described here, without the level descending below a minimum level located above the supply tap of a pipe 65 connecting the base of the

  reservoir to the suction duct 66 of the liquid ring pump.

  Thus, the liquid ring can be supplied by recirculation of a portion of the wastewater, the flow in the conduit 65 being effected without auxiliary pump, under the effect of the depression created by the liquid ring pump. A clear water supply 45 is however necessary in the starting phase of the pump. This

  power supply is then cut off by the valve 46.

  In such a system comprising a storage tank another preferred arrangement also shown in Figure 6 is to extend the discharge line 71 of the liquid ring pump to the bottom of the tank. Thus, the air discharged by the pump escapes from the discharge pipe in the form of bubbles. This bubbling is conducive to the aerobic degradation of

  materials contained in the tank.

  In a third system according to the invention shown in Figure 7, the liquid ring pump is also used for emptying the storage tank. More particularly, there is used temporarily a possibility of liquid ring pumps which is known in itself and according to which such a pump can operate in air compressor. To empty, a separation valve 81 is closed through which the storage tank is connected to the vacuum network and an air introduction valve 82 is opened which enables communication

  with the atmosphere. The pump then draws air at atmospheric pressure.

  that it compresses by pushing it back into the tank. We also have

  closed a valve 83 located on the vent of the tank.

  If then opens a valve 84 for emptying the tank, it results in a pressure drain thereof. It is thus possible to discharge the wastewater in a drain line 86 to

  a collector duct 88 located higher than the tank.

- 12 -

Claims (9)

  1 / Vacuum evacuation system of wastewater in which the   Wastewater is sucked up and discharged by a liquid ring pump.   2 / wastewater evacuation system comprising - a tubular collector (42) for receiving said wastewater in the form of successive plugs, and air masses resulting from these plugs and from the atmosphere , and connected circulation, suction and discharge means   to this manifold to suck up these plugs and these masses of air consecutive   reducing the air pressure in said manifold to a suction pressure lower than atmospheric pressure, and for discharging said wastewater under a discharge pressure greater than said suction pressure and sufficient to allow their evacuation,   this system being characterized by the fact that said means of circula-   suction and discharge include -   - a liquid ring pump (P) provided with a suction passage (33)   connected to said manifold, a discharge passage for the evaluation   cuation said waste water, and a water supply passage to receive a minority flow of a clean feed water to form and / or maintain a liquid ring in this pump, and water supply means (45, 46) to provide said feed water.   3 / A system according to claim 2, wherein said circulation, suction and discharge means further comprise a reservoir (61) receiving and temporarily containing said wastewater under a storage pressure greater than said suction pressure, this reservoir (61 ) being connected to the said passage of   delivery (34) of said liquid ring pump (P).   4 / System according to claim 3, characterized in that   supply pipe (65) connects a lower part of said reservoir   see (61) said suction passage (33) of said liquid ring pump (P) so as to suck up a minority flow of wastewater from said reservoir to maintain said liquid ring, said supply means (46) ). in water supplying water 2628459- - 13 -   clear and being controllable so that it can stop providing that clear water when that ring can be serviced by that used water.   / System according to claim 3, characterized in that it further comprises valves (81, 82) and pipe (86) to allow, after a period of storage of said waste water in said reservoir which then constitutes a storage tank (61), to drain this tank under the action of suction and discharge of said liquid ring pump.   6 / A system according to claim 5, in that said valves and pipe to allow said tank to drain comprise - an air introduction valve (82) which when open communicates said suction passage (33). ) of said liquid ring pump (P) with the atmosphere, - a separation valve (81) which, when closed, eliminates the connection of this suction passage (33) to said manifold (42), - and a drain line (86) connecting a bottom portion of said storage tank (61) to a drain area (88) such that in a storage period during which said air inlet valve is closed and this open separation valve, this pump sucks said plugs and said consecutive air masses and discharges said waste water into said storage tank to store the waste water, and so that in a period of emptying during which this valve introductory of air is opened and this closed separation valve, this same pump sucks a flow of air from the atmosphere and forces this flow of air into said storage tank under a drain pressure which constitutes said pressure of evacuation and which is greater than the atmospheric pressure and said storage pressure, whereby this flow of discharged air itself represses, through said drain pipe, the wastewater that has been stored in this reservoir during a so-called previous storage period.  7 / System according to claim 6, characterized in that said storage tank is provided with a ventilation valve which is located at the top and which is closed during said period -14- 685   of emptying, and a drain valve (84) which is located on said drain line (86) and which is open during this period emptying.   8 / A system according to claim 2, characterized in that said collector (42) is connected to said suction passage (33) of said liquid ring pump via a trap with heavy particles (51).   9 / System according to claim 3, for the discharge of wastewater containing organic materials whose polluting power can be reduced by aeration continued during a suitable aeration time, this system being characterized in that said reservoir is a storage tank (61) for storing said waste water during said aeration time, and said discharge passage (34) communicates with this reservoir via a discharge line (71) opening at the bottom of this outlet; tank, so that the air discharged by this pump rises in the form of bubbles through the thickness of stored wastewater in this tank.   The system of claim 1 wherein said liquid ring pump (P) comprises a pump body (12) having a generally cylindrical peripheral wall (12B) about a body axis (12A), a rotor (11) ) provided with blades (11A), having a rotor axis (11B) and rotating in this body about this axis, the latter being offset with respect to said body axis, - a motor (10) for driving this rotor, - a distributor (16) constituting a wall in contact with the internal space at said pump body, - a suction port (21) and a delivery port (22) drilled in this distributor, - and a supply passage (19 ) for introducing water into said body so that the water thus introduced constitutes a liquid ring rotated by said rotor blades and pressed by the centrifugal force against said peripheral wall - 15 -   (12B) and that separate rotating pumping chambers are constituted by these blades and this ring and that they suck a fluid to be pumped through said suction lumen and push it back through said discharge lumen, - this system being characterized in that said suction lumen (21) is sufficiently wide to contain a circle of approximately mm diameter, so as to facilitate the suction of materials   not strong which can be part of said plugs.   The system of claim 10, wherein said liquid ring pump (P) is further provided with tubular suction (33) and discharge (34) passages connected respectively   said suction (21) and discharge (22) ports and   each being an axis (33A, 34A), this system being characterized by the fact that said axis (33A) of said suction passage (33) and preferably that (34A) of said discharge passage (34) are substantially parallel to said axes of body (12A) and rotor (11B) and that their extensions pass substantially through said suction ports (21) and backflow (22), respectively.