WO1992020624A1

WO1992020624A1 - Methods and apparatus for producing potable water

Info

Publication number: WO1992020624A1
Application number: PCT/US1992/003981
Authority: WO
Inventors: Donald M. Stearns
Original assignee: Pec Research, Inc.
Priority date: 1991-05-15
Filing date: 1992-05-14
Publication date: 1992-11-26
Also published as: AU1996592A

Abstract

This invention is a method and apparatus for removal of organic matter from a conventional surface or subsurface source of water, or from an effluent from advanced wastewater treatment processes, to produce potable water. The process is accomplished by dissolved and entrained air stripping in a stripping column (13), followed by contact with activated carbon in an activated carbon/water absorption reactor (23), and separation of the activated carbon from the water in contact columns (27). The spent activated carbon is regenerated by the use of low pressure steam and vacuum, with the continuous recirculation of the regenerated activated carbon back to the first stage reactor (23) of the treatment process. The process utilizes a constant rate of raw water feed (11) to provide efficient control of the addition of activated carbon in the amounts required. A unique diffuser body (15) having at least one baffle provided therein for dissolving the flotation gas in the liquid to be treated is also disclosed.

Description

Method and Apparatus for Producing Potable Water

Related Applications

This patent application is a continuation-in-part of US Patent Application serial number 07/587,048, filed September 24, 1990 which is a division of application serial number 07/301,463 filed January 26, 1998, now U.S. Patent Number 4,976,863.

Technical Field

This application relates to a method and apparatus for producing potable water.

Background Art

Supplies of raw water, for conversion into potable water, have been greatly reduced in the entire world by organic contamination from several sources. The primary sources are disposal of incompletely treated wastewater, disposal of toxic organic materials in land fills, surface dumping of toxic organic waste products and the accidental discharge of toxic organic matter into waterways. Even in the most advanced wastewater treatment plants, disposal of the treated effluent, by any current means, does not prevent the destruction of the source of potable water in the area of its disposal. No means of removal of the toxic organic matter from the wastewater has been provided in any currently applied treatment system.

Years of disposal of toxic organic materials in unprotected landfill sites has also caused vast contamination of subsurface water supplies in the many industrial areas of the world, further reducing the sources of supply of raw potable water. Surface dumping of toxic organic materials have, over the years, caused contamination of a high percentage of subsurface water with the resulting loss of sources of raw water suitable for conversion into potable water.

Disclosure of Invention

The Method and Apparatus for Producing Potable water is intended to provide a means of utilization of sources of raw Water for conversion into potable water, not disclosed in prior art. This means can be used for the removal of organic contamination from subsurface and surface water sources, by closed loop recirculation of the contaminated subsurface and surface water for the purpose of removal of toxic organic material and the return of the purified water into its original source in a condition suitable for environmental use. The Method and Apparatus For Producing Potable Water is designed for the specific application of receiving the treated effluent from the water recovery energy producing sludge elimination wastewater treatment process as disclosed in U.S. Patent # 4,976,863, the contents of which are hereby incorporated by reference. Other contaminated raw water sources, that do not need chemical treatment for the removal of inorganic dissolved solids or the removal of solids, are subjects for treatment by the means. The process is based on the application of a small amount of granular activated carbon contact to remove all of the organic matter from the raw water source by surface absorption and physical attachment of the organic to the surface of the carbon. A high efficiency air stripping device for removal of organic matter lowers the amount of organic material that the carbon must remove. The raw water received from the water recovery energy producing sludge elimination wastewater treatment plant or other sources, is introduced into the apparatus for production of potable water by way of (15) the multi-injection diffuser where compressed air is contacted with the water to produce both dissolved and entrained air in the water. As the use of both dissolved air, which provides the smallest size bubbles (micro-bubbles) of air, and the entrained air which provides both the medium and large size air bubbles, are required due to the random size of the organic droplets in the water that must be removed.

The water with dissolved air and entrained Air is introduced into the bottom area of the (13) organic reduction air stripper column under pressure which provides a range of bubble sizes, from that of the micro-bubble of the dissolved air, to the larger size of the entrained air, thus matching the bubble size range of the organic droplets. The compressed air is introduced into the water in the (15) multi-injection diffuser, which combines, turbulence, vortex action and the change in flow direction in a single element. The turbulence is caused by the impact of the high velocity water with the blades of the diffuser element in several stages. The direction of flow of the high velocity water is changed in each stage by the angle of the blades thus requiring the water to make rapid changes in direction which in turn causes eddy currents in the area of the deflection, resulting in further turbulence. The difference in gravity between the air and the water, causes the rapid separation of the air from the water with the air collecting at the highest point in the diffuser body. To re-inject this air, a vortex turbulence is caused by the injection of higher pressure water into the top of the diffuser body just in front of each diffuser element thus causing a vortex flow just prior to fluid contact with the blades of the diffuser element, which in turn provides a third type of turbulence within the diffuser.

The increase in pressure causes the amount of dissolved oxygen in the water above normal saturation levels of air in water at normal atmospheric pressure. As the water that is supersaturated with air is introduced into the bottom area of the (13) organic reduction air stripper column, the pressure is reduced from the level of pressure maintained within the (15) multi-injection diffuser. As the solubility of air in water is a function of pressure, on entering the (15) organic reduction air stripper column, at a lower pressure, dissolved air is released from solution in the form of micro-bubbles. The release of the air from the water in the form of micro-bubbles, which due to their small size, provides a major means of removal of the organic material from the raw water. In order to maximize the contact time between the organic droplets and the air bubble, a baffle system is used to change the direction of flow from vertical to horizontal and then back to vertical in a number of stages. As the supersaturated water continues to rise in the (13) organic reduction air stripper column, air micro-bubbles are continuously released due to the reduction in pressure as the water rises through the height of the column. As the released air bubbles have a very low density, their vertical rise rate is much greater than that of the water and thus produce the means of removal of the low density organic matter that is entrained.

In the baffled section of the (13) organic reduction air stripper column, the objective is to provide adequate contact time between the air bubble and the organic droplet for the attachment of the air bubble to the organic droplet. In the unbaffled section of the (13) organic reduction air stripper column, free raise of the organic droplet and the attached air bubble is provided. For the organic droplets with attached air bubbles, that do not have sufficient difference in gravity for a free raise rate in the water, a high air velocity section is provided in the (13) organic air stripper column in which large size air bubbles are impacted into the slow raising air and organic droplet in order to increase their ability to be separated from the water by impact stripping. This is the third and final method used in the (13) organic reduction stripper column of organic removal. After traveling the height of the (13) organic reduction air stripper column, the water flows by gravity into the (23) activated carbon/water absorption reactor. As the raw water is introduced at a constant rate, the slurry of activated carbon in water are added to the (23) activated carbon/water absorption reactor by the (45) activated carbon slurry feed pump at a constant rate. The (23) activated carbon/water absorption reactor is designed large enough to provide sufficient time for surface absorption of the organic matter, from the Water discharged from the (13) organic reduction air stripper column which was not removed by air stripping alone.

The (23) activated carbon/water absorption reactor is equipped with the (21) vertical turbine mixer that provides full suspension of the activated carbon in the water that will allow adequate contact between the surfaces of the activated carbon and the organic for the absorption of the organic matter in the water by the surface of the activated carbon.

The water and activated carbon mixture is removed from the (23) activated carbon/water absorption reactor by means of the (25) centrifugal pump, at a constant rate, and delivered to the (27) contact columns. The (27) contact columns have a dual function in handling the water/activated carbon mixture, that of, (1) the final step of organic matter removal and (2) the separation of the granular activated carbon from the water. After passing through one of the (27) contact columns, the water flows through the (31) condenser, which could be a shell and tube type, with water passed through the tubes so that the shell can act as a condenser during the reactivation cycle.

As the (31) condenser is only used during the generation step of the activated carbon, it is possible to bypass the water flow around the (31) condenser during the times that none of the (27) contact columns require the regeneration of the spent granular activated carbon. After passing through the (31) condenser, or the bypass, the water enters one of the (51) trap filters for the purpose of removal of activated carbon particles that are produced as a result of mixing and pumping applications in the process system. It would be expected that only a small amount of the activated carbon would not be retained by the bed of activated carbon in the (27) contact columns.

The (51) trap filter would be of the pressurized type and could be of the removable media, precoat or backwashable type. To minimize the production of wastes, that would require disposal, the best selection would be a removable media type of either the disposal or cleanable media type. After passing through one of the (51) trap filters, the potable water would be treated with a normal amount of Chlorine or other means that would provide protection for the water while in storage or in the distribution system. As chlorination is still the recommended means of providing this protection, the (57) chlorinator and the (55) chlorine storage cylinders are included in the treatment process.

After chlorination, the potable water is introduced into the (57) potable water storage tank. Storage of the potable water is required as the potable water recovery plant operates at a constant rate of flow and the demands for potable water in any supply system vary greatly, depending upon the time of day. The (59) high service centrifugal pumps and the (61) potable water supply pipeline would be the same as those presently in operation at all potable water Treatment Plants. One of the unique features of the Method and

Apparatus disclosed in this application is the inplace regeneration of the spent activated carbon in the (27) contact columns. When the amount of activated carbon . collecting within one of the (27) contact columns reaches a level at which the pressure drop exceeds the normal range of operation, the pressurized flow into the (27) contact column is shut-off and the first step in the regeneration sequence is started. Compressed air is introduced into the top of the (27) contact column and the Water in the (27) contact column is discharged into the (37) activated carbon holding tank. After all of the water in the (27) contact column has been transferred, the compressed air from the (17) compressed air storage tank is terminated.

The (27) contact column is then vented in order to allow air to escape from the tank. Low pressure steam provided by pipeline (29) low pressure steam pipeline is introduced into the bottom of the (27) contact column and in turn passes through the bed of spent activated carbon and is discharged through the vent. The source of the steam could be from the boiler of the Water recovery Energy Producing Sludge Elimination Wastewater Treatment Plant if it was in a nearby location, or a steam generator.

In the first step of the activated carbon regeneration process, sufficient steam would be required to rise the temperature of the activated carbon bed to a minimum of 225 degrees F. After reaching temperature, the feed of steam would continue at a higher rate for a minimum of one hour with the tank vented to provide a high steam velocity through the activated carbon bed. The final step in the process to regenerate the spent activated carbon is the reduction of the steam rate of feed to that minimum required to maintain the 225 degree F temperature of the bed with the vent closed and the steam discharged into the (31) condenser. The condensing of the steam in the (31) condenser forms a vacuum in the (27) contact column which in turn, completes the removal of organic matter from the surface of the spent activated carbon and returned it to an active condition. The complete plant flow of potable water is used to provide the cooling and condensing of the steam in the (31) condenser. The vacuum condition should be maintained for a minimum of one hour for final removal of all organic material from the surface of the activated carbon. After completion of the vacuum cycle, the (27) contact column is vented and a valve opened at the bottom of the column to allow water/activated carbon mixture from the (25) centrifugal pump to enter the (27) contact column from the bottom in place of the normal feed into the column from the top. At the same time, compressed air from the (17) air compressor storage tank is injected into the same pipeline carrying the water/active carbon mixture into the bottom of the (27) contact column, thus changing the compacted bed of activated carbon into a fluid media which can be discharged through a valve and pipeline located just above the retainer screen into the 37) activated carbon holding tank.

The (37) activated carbon holding tank is equipped with the (39) vertical turbine mixer in order to provide a uniform suspension of the activated carbon in the water. The activated carbon water suspension is transferred from the (37) activated carbon holding tank by the (41) centrifugal slurry pump into the (43) activated carbon slurry feed tank.

The (43) activated carbon slurry feed tank is equipped with the (47) vertical turbine mixer in order to provide for the mixing of the new activated carbon needed to make up for the losses of activated carbon and to maintain a full uniform suspension of the activated carbon water mixture, so that it was ready for transfer. The new activated carbon would be added by use of an enclosed water flushed dump hopper, or some similar device, by way of the (49) gravity pipeline.

The activated carbon water slurry would be returned to the (23) activated carbon/water absorption reactor by the (45) activated carbon slurry metering pump. This completes the closed loop process for the production of potable water.

For the purification of contaminated subsurface or surface water, most of the equipment defined for the production of potable water would be used and mounted on a group of low bed trailers so it could be moved from site to site. The equipment not required for the purification operation would be the (51) trap filters, (53) chlorinator, (57) the potable water storage tank, the (55) chlorine storage cylinders and the (59) the high service centrifugal pumps. Additional equipment required to make the system self-contained would be a fuel storage tank for LPG or diesel fuel, an engine driven generator, a steam generator and a control panel for the generator.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1. is a flow diagram for a permanent plant installation for the production of Potable Water. Fig. 2. is a sectional assembly drawing of the

(15) multi-injection diffuser.

Fig. 3. is a top plan view of the (205) gas inlet ring.

Fig. 4. is a top plan view of the (207) injection spacer inlet sleeve.

Fig. 5. is a top plan view of the (215) discharge directional ring.

Fig. 6. is a top plan view of the (209) diffuser reversible baffle. Fig. 7. is a sectional drawing of the (13) spiral flow organic reduction air stripper column.

Fig. 8 is a top plan view of the( 713) water distributor for introduction of the water into the high velocity stripping section of the (27) air stripper column.

Fig. 9 is a top plan view of the (716) air distributor for introduction of air into the high velocity stripping section of the (27) air stripper column. Fig. 10 is a sectional drawing of the (27) contact column.

Fig. 11 is a top plan view of the (1003) retention screen.

Fig. 12 is a top plan view of the (1006) support grid for the (1003) retention screen.

Fig. 10 is an arrangement drawing for a mobile trailer mounted Apparatus For Producing Potable Water as used for purification of contaminated surface or subsurface water or the temporary production of potable water from sources with organic contamination.

Best Mode For Carrying Out The Invention

With reference to Fig. 1 the system flow diagram, most of the equipment applied to the apparatus for producing potable water is commercially available and includes tanks, mixers, pumps, heat exchangers and filters. The three items of equipment that are of a unique design are the (15) multi-injection diffuser, the (13) spiral flow organic reduction air stripper column and the (27) contact columns. Systems such as the (17) and (19) compressed air, (53) and (55) chlorinator and the (33) condensate return are all available from standard suppliers.

Fig. 2. provides a sectional assembly drawing of the (15) multi-injection diffuser which is intended to operate at a minimum pressure of 15 PSIG, but more normally at a pressure of 30 PSIG. The (15) multi-injection diffuser provides a range of finely entrained air bubbles but more importantly, increases the amount of dissolved air which will be released as the pressure is reduced in the (13) spiral flow organic reduction air stripper column. The components of the (15) multi-injection diffuser includes the (201) inlet spool body, the (203) diffuser body, the (205) gas inlet ring, the (207) injection spacer inlet sleeve, the (209) diffuser reversible baffle, the (211) "0" ring, the (213) discharge spool piece, the (215) discharge directional ring, the (217) flow control valves and the (219) anti-rotation locking bar.

Fig. 3. is a top plan view of the (205) gas inlet ring that shows the method of introduction of the air into the high velocity water flow which provides opposed injection of the air into the water at a 90 degree angle. The opposed flow of the air and the 90 degree angle of injections provides the initial dispersion of that air in the water. The (205) gas inlet ring has a slot for positioning and anti-rotation using the (219) anti-rotation locking bar.

Fig. 4. is a plan top view of the (207) injection spacer inlet sleeve with injection port and anti-rotation slot.

Fig.5. is a plan top view of the (215) discharge directional ring which rotates the water and dissolved and entrained air to cause a circular motion in addition to the normal linear movement.

Fig. 6. is a plan top view of the (209) diffuser reversible baffle showing the deflected flow and knife edge which cause turbulence for entrainment of the air in the water flowing at high velocity.

Fig. 7 shows the spiral flow organic air stripper column divided into two different sections, each with a different function. In the bottom section, the water with dissolved air and entrained air is introduced into the column in a manner that produces a spiral flow. A helix spiral baffle provides a means of reducing the vertical travel rate of the entrained air and the dissolved air that comes out of the water as the pressure is reduced. This provides the contact time with the organic contaminants in the water to allow attachment of the air to the entrained organic matter and thus a high degree of removal of the organic matter in the low velocity section of the organic reduction air stripper column. After the water rises to the top of the low velocity section of the column, it flows over a "V" notch weir and on to the (713) water distributor. Air is introduced under the (716) air distributor and, to maintain a uniform backpressure, a height of water is provided over the (716) air distributor by the proper placement of the outlet nozzle. This uniform backpressure, and the design of the air distributor provides uniform flow of the air flow around the diameter of the column. The high velocity air bubbles impact the droplets of water and remove any remaining micro-bubbles of air attached to the organic matter in the water.

Other items shown in Fig. 7 are the (734) inlet, the (731) helix baffle, the (728) baffle support, the (706) air inlet, the (709) water outlet, the (722) "V" notch weir and the (710) air vent. Fig. 8 is a top plan view of the water distributor of the high velocity section of the organic reduction air stripper column and the opening are designed to provide minimum size droplets of water under the conditions of allowing normal release of the high velocity air, reasonable height of retained water over the distributor, flow rate of the column and the diameter of the column.

Fig. 10 is a sectional drawing of the (27) contact column showing the internal arrangement and the external valving arrangement that allows the (27) contact column to operate in the following manner. For filling the (27) contact column valve (1018) is opened to allow the slurry of activated carbon and water to enter the (27) contact column. At the same time valve (1022) is opened to allow venting of the air from the (27) contact column. After filling is complete, valve (1022) is closed and valve (1008) opened to direct the discharge of the purified water to the (31) heat exchanger tubes or to a bypass around the tubes of the (31) heat exchanger. As cooling water is only needed during the reactivation cycle of the activated carbon, pump energy can be reduced by the use of a bypass valve on the tube side of the (31) heat exchanger.

During the production cycle of the (27) contact column valve (1018) is opened to allow entrance of the water/activated carbon slurry into the top of the (27) contact column and valve (1008) is opened to direct the purified water to the (31) heat exchanger tubes (or bypass) . The final purification of the water is obtained by filtering the water through the bed of activated carbon that is retained on the (1003) retainer media with the water flowing through the

(1006) support grid. This process is continued until a pre-determined pressure loss is reached across the bed of the activated carbon collected on top of the (1003) retainer media. After completion of the production cycle of the

(27) contact column, the (1018) valve is closed and the flow of water and activated carbon slurry is directed to another (27) contact column. The (1010) valve that directs the flow of purified water to the (31) heat exchanger is closed and the (27) contact column is now ready to start the regeneration cycle of the spent activated carbon. Valve (1020) is opened to allow compressed air from the (17) compressed air storage tank to enter the (27) contact column and valve (1010) is opened to drain the contents of the (27) contact column to the (37) activated carbon holding tank. The (1010) valve remains open to allow an additional air drying time for the bed of spent activated carbon retained on the (1003) retention media. After completion of the air drying cycle, valves (1010) and (1020) are closed and valves (1022) to the (35) vent and valve (1012) to the (29) low pressure steam pipeline are opened. A low volume of steam is introduced into the bottom of the (27) contact column until the bed of activated carbon reaches a minimum temperature of 225° F. In the event, the amount or the toxic level of the organic matter is too great for open air discharge, the (1022) valve to the (35) vent would be closed and the (1024) valve to the shell side of the (31) heat exchanger would be opened and the steam and organic matter would be condensed. For this mode of operation, the (33) condensate return pump would not be directed to the (37) activated carbon holding tank, but to a tank wagon for off site separation of the water and toxic organic material. When the spent activated carbon bed reaches the minimum stripping temperature the steam rate would be increased for 30 to 60 minutes at higher velocity for higher temperature/higher velocity stripping of the organic matter from the surface of the activated carbon. After completion of this part of the regeneration cycle, the steam rate would be reduced to a minimum point that would maintain the temperature of the carbon bed at 225° F, the (1022) valve would be closed and the (1024) valve to the shell side of the (31) heat exchanger would be opened. By condensing the steam, a vacuum is produced in the (27) contact column which is required to remove the final amount of organic matter from the surface of the spent activated carbon. The vacuum should be maintained for 30 to 60 minutes dependent upon the organic material being removed and the relationship between the maintenance of the minimum temperature of the carbon bed and the vacuum produced. After completion of the regeneration of the spent activated carbon, valve (1012) is closed to stop the feed of steam. Valve (1024) is closed to stop the condensation in the shell of the (31) heat exchanger and valve (1022) is opened to relieve the vacuum in the (27) contact column. Valve (1022) is closed after venting of the (27) contact column and valve (1005) is opened to allow the discharge of the activated carbon into the (37) activated carbon holding tank. Valve (1016) , the feed line for the water and carbon slurry is opened and the (1014) valve is opened to provide a mixture of water and compressed air from (17) the compressed air storage tank to enter the bottom of the (27) contact column. The mixture of water and air provide turbulence and fluidization of the activated carbon bed which than can be transferred to the (37) activated carbon holding tank by using the pressure available from the compressed air. After the activated carbon is transferred to the (37) activated carbon holding tank, valves (1016), (1012) and (1005) are closed for the final step in the regeneration cycle. In order to remove the water and activated carbon slurry from the bottom section of the (27) contact column, valve (1020) is opened to allow the entrance of compressed air from (17) compressed air storage tank and the drain valve (1010) is opened to blow the bottom contents of the (27) contact column back to the (37) activated carbon holding tank. The (27) contact column is now ready to be returned to the production cycle.

The completion of the closed loop separation and reactivation of the carbon uses the (41) centrifugal slurry pump to transfer the water activated carbon slurry from the (37) activated carbon holding tank to the (43) activated carbon slurry feed tank. Any additional activated carbon need to replace losses due to breakdown of particle size is added by (49) the activated carbon loss replacement pipeline. Additions of the water activated carbon slurry to the (23) activated carbon/water absorption reactor are provided by the (45) activated carbon slurry matering pump.

Fig. 13 provides the preferred arrangement of a portable system mounted on four lowboy type trailers complete with a steam generator (73) , an engine driven electric generator (75) , fuel storage tank (71) and an electrical control panel (77) . The preferred fuel for the steam generator and engine would be LPG. The inter-connections between the trailer would be flexible metal or flexible plastic hoses. The following is a listing of the equipment shown on the preferred arrangement drawing Fig. 13: (13) organic reduction air stripping column. (15) multi-injection diffuser. (17) Air compressor storage tank. (19) Air compressor.

(21) Vertical turbine mixer.

(23) Activated carbon/water absorption reactor.

(25) Centrifugal pump. (27) Contact columns.

(31) Condenser.

(33) Condensate return pump.

(37) Activated carbon holding tank.

(39) Vertical turbine mixer. (41) Centrifugal slurry pump.

(43) Activated carbon slurry feed tank.

(45) Activated carbon slurry metering pump.

(47) Vertical turbine mixer.

(51) Trap filters. (53) Chlorinator.

(55) Chlorine storage cylinders.

(57) Potable water storage tank.

(59) High service pump.

(63) Lowboy trailers. (71) LPG storage tank.

(73) Steam generator.

(75) Engine driven generator.

(77) Electrical control panel.

Claims

CLAIMS :

1. A method for removal of organic contaminants from raw water to produce potable water comprising: dissolving and entraining a gas into said raw water at a first pressure; introducing said raw water having said gas dissolved and entrained therein into a first column; reducing the pressure to a second pressure lower than said first pressure, thereby allowing said gas to be released from said raw water in the form of micro-bubbles to which Low density organic material in said water attaches; introducing water from said first column into a reactor; introducing activated carbon into said reactor; maintaining said activated carbon and said water in said reactor for a period of time sufficient to allow organic matter in said water to be absorbed on surface of said activated carbon; and removing said activated carbon and adsorbed organic matter from said water, thereby producing potable water.

2. A method according to Claim 1, wherein and activated carbon and surface absorbed organic matter is removed from said water in a contact column, said method further comprising regenerating said activated carbon in said column by removing said adsorbed organic matter therefrom.

3. An apparatus for removal of organic contaminants from raw water to produce potable water, comprising; means for dissolving and entraining a gas into said raw water at a first pressure; a column through which said raw water having said gas dissolved and entrained thereon can pass and in which the pressure on said raw water can be reduced; means for introducing said raw water having said gas dissolved and entrained therein into said column; a reactor; means for introducing raw water from said column to said reactor; a source of activated carbon; means for introducing said activated carbon into said reactor; means for removing activated carbon from said raw water.

4. An apparatus according to claim 3, further comprising means for regenerating said activated carbon removed from said raw water and means for recirculating the regenerated activated carbon to said source of activated carbon.

5. An apparatus for dissolving gas in a liquid, comprising: a diffuser body through which said liquid flows, said diffuser body having an inlet and an outlet; means for introducing said gas into said diffuser body near said inlet thereof; at least one baffle provided in said diffuser body between said inlet and said outlet for causing turbulence in the flow of liquid through said diffuser body and causing a decrease in pressure from said inlet to said outlet; means for delivering said liquid under pressure to said inlet of said diffuser body.