CN117228925B - A fixed excrement solid-liquid separation device and separation method thereof - Google Patents

Abstract

The present invention discloses a fixed solid-liquid separation device for manure and sewage and a separation method thereof, which relates to the technical field of solid-liquid separation of manure and sewage, and comprises a cylinder, a screen cylinder is arranged in the middle of the cylinder, a fixed shaft is arranged in the screen cylinder, and the two ends of the fixed shaft rotate and penetrate the two side walls of the cylinder; a plurality of first spiral blades are fixedly arranged on the right side of the fixed shaft, a plurality of second spiral blades are fixedly arranged on the middle section of the fixed shaft, and a plurality of third spiral blades are fixedly arranged on the left side of the fixed shaft; a pair of fixed ear seats are fixedly arranged on the top surface of the cylinder, a fixed shaft is rotatably arranged between the tops of the pair of fixed ear seats, a linkage shaft is rotatably arranged between the bottoms of the pair of fixed ear seats, and the linkage shaft is connected to the screen cylinder through a meshing assembly. The present invention greatly improves the efficiency of solid-liquid separation and efficiently utilizes resources, can more conveniently carry out composting or other treatments, and reduces pollution to the environment.

Description

A fixed excrement solid-liquid separation device and separation method thereof

Technical Field

The present invention relates to the technical field of solid-liquid separation of feces and sewage, and in particular to a fixed solid-liquid separation device for feces and sewage and a separation method thereof.

Background Art

Fixed manure solid-liquid separation equipment mainly separates solids and liquids in manure by physical and mechanical methods. The main components of fixed manure solid-liquid separation equipment include mechanical screens, screw conveyors and liquid collectors. After the manure is separated into solid and liquid parts by mechanical screens, the solid particles are sent to the solid collector by screw conveyors, while the liquid part is collected in the liquid collector.

As disclosed in a Chinese invention patent, a fixed solid-liquid separation and treatment device for manure (publication number CN108339321A) is composed of a double-box vacuum liquid extraction system, a liquid distribution system, a multi-stage secondary filtration system, a multi-function box, a belt extrusion filtration system, a wiring control box, a solid discharge hopper, a frame, and a belt primary filtration system.

Compared with traditional treatment methods, the current solid-liquid separation equipment for manure has relatively high investment and maintenance costs for fixed separation equipment, poor solid-liquid separation effect, inconvenient cleaning, low work efficiency, and high treatment equipment costs, which leads to a large amount of manure flowing into rivers.

Summary of the invention

The purpose of the present invention is to solve the shortcomings of the existing manure solid-liquid separation equipment in the prior art, such as poor solid-liquid separation effect and inconvenient cleaning, and to propose a fixed manure solid-liquid separation equipment and a separation method thereof.

In order to solve the problems existing in the prior art, the present invention adopts the following technical solutions:

A fixed solid-liquid separation device for manure, comprising a cylinder, the cylinder being a hollow cylinder with a thick middle portion and thin ends, a slag discharge port being provided on the left side of the bottom surface of the cylinder, a liquid discharge port being provided in the middle of the bottom surface of the cylinder, and a feed port being provided on the right side of the top surface of the cylinder;

A screen cylinder with two ends rotatably connected is provided in the middle of the cylinder, and a concentrically distributed fixed shaft is provided in the screen cylinder, and the two ends of the fixed shaft rotate and penetrate the two side walls of the cylinder;

The right side of the fixed shaft is fixedly provided with a plurality of first spiral blades distributed at equal distances, the middle section of the fixed shaft is fixedly provided with a plurality of second spiral blades distributed at equal distances, and the left side of the fixed shaft is fixedly provided with a plurality of third spiral blades distributed at equal distances;

A plurality of the first spiral blades are continuously spirally fixed, a plurality of the second spiral blades are spaced apart from each other, and a plurality of the third spiral blades are continuously spirally fixed;

A pair of fixed ear seats are fixedly arranged on the top surface of the cylinder body, a fixed shaft which is rotatably arranged to penetrate horizontally is arranged between the tops of the pair of fixed ear seats, a linkage shaft which is rotatably arranged to penetrate horizontally is arranged between the bottoms of the pair of fixed ear seats, and the linkage shaft is connected to the screen cylinder through a meshing assembly.

Preferably, a pair of concentrically fixed rings are sleeved on both sides of the cylinder, and vertically distributed fixing rods are fixed on the front and rear sides of the outer ring surface of each fixing ring.

Preferably, a pair of symmetrically distributed channel steel rings are fixedly provided at both ends of the screen cylinder, a pair of channel steel clamping rings are fixedly provided in the middle of the cylinder body, and each of the channel steel rings is rotatably clamped on the corresponding channel steel clamping ring.

Preferably, a rotatably connected baffle is sleeved on the left side of the fixed shaft, a tension spring is fixedly provided on the left side surface of the baffle, the tension spring is sleeved on the fixed shaft, and the left end of the tension spring is fixedly connected to the left inner wall of the cylinder.

Preferably, a pair of concentrically fixed retaining rings are sleeved on both sides of the screen cylinder, the pair of retaining rings are located between a pair of gear rings, and the outer ring surface of each retaining ring is rotatably connected to the inner wall of the cylinder.

Preferably, the meshing assembly includes a gear ring and a linkage gear, a pair of concentrically fixed gear rings are sleeved on both sides of the outer ring surface of the screen cylinder, a pair of elliptical through holes are opened on the top surface of the cylinder body, and a pair of concentrically fixed linkage gears are sleeved on both sides of the linkage shaft, and each of the linkage gears passes through the corresponding elliptical through hole and is meshed with the gear ring.

Preferably, a pair of concentrically fixed driving gears are sleeved on the fixed shaft, each of the driving gears is meshedly connected with the linkage gear on the corresponding side, and the leftmost end of the fixed shaft is coaxially fixed with the motor shaft end of the servo motor.

Preferably, the right end of the fixed shaft rotates through the feed inlet and extends to the outside, and a plurality of flapping blades are fixedly arranged on the right side of the fixed shaft, and the plurality of flapping blades are located in the feed inlet;

The right end of the fixed shaft is sleeved with a concentrically fixed driving pulley, and the right end of the fixed shaft is sleeved with a concentrically fixed driven pulley. The driving pulley is transmission-connected with the driven pulley via a linkage belt.

Preferably, a backwash pump is fixedly provided on the left side of the top surface of the cylinder, and a pair of backwash pipes are provided at the flushing end of the backwash pump. The pair of backwash pipes are distributed on the front and rear sides of the linkage shaft, and each of the backwash pipes is provided with a plurality of backwash nozzles, and each of the backwash nozzles passes through the cylinder and faces the screen cylinder.

The present invention also proposes a separation method of a fixed feces solid-liquid separation device, comprising the following steps:

Step 1, start the servo motor, the motor shaft of the servo motor drives the horizontal shaft, a pair of driving gears, a plurality of flap blades and the driving pulley to rotate synchronously, and the driving pulley drives the driven pulley, the fixed shaft, the first spiral blade, the second spiral blade and the third spiral blade to rotate synchronously through the linkage belt;

Step 2: When the driving gear rotates, the driving gear meshes to drive the linkage gear and the linkage shaft to rotate in the opposite direction, and the linkage gear meshes to drive the gear ring and the screen drum to rotate slowly in the forward direction, so that a certain speed difference is maintained between the fixed shaft and the screen drum;

Step 3: Under the rotation of the flipping blades, the manure liquid enters the right side of the cylinder through the feed port, and under the spiral action of the first spiral blade, the manure liquid is driven into the screen cylinder. Since there is a gap between the second spiral blades, the manure liquid is fully squeezed in the screen cylinder and solid-liquid separation is performed;

The separated liquid is discharged through the liquid discharge port, and the separated residue is continuously transported under the spiral action of the third spiral blade, and is discharged through the residue discharge port under the squeezing action of the tension spring and the baffle plate;

Step 4: After the solid-liquid separation of the manure and sewage is completed, the servo motor keeps rotating normally and starts the backwash pump. Under the action of the backwash pump, clean water enters the backwash pipe after being pressurized, and the screen drum is backwashed and cleaned through several backwash nozzles.

Compared with the prior art, the present invention has the following beneficial effects:

1. In the present invention, under the cooperation of the meshing assembly, the fixed shaft and the screen drum rotate in the same direction while maintaining a speed difference, and under the action of each spiral blade, the feces and sewage raw liquid are fully separated into solid and liquid; the solid particles and liquid in the feces can be effectively separated, and the utilization rate of the liquid fertilizer part of the feces can be improved;

2. In the present invention, under the action of the backwash pump, clean water enters the backwash pipe after being pressurized, and the screen cylinder is backwashed and cleaned through a number of backwash nozzles; by separating the solid and the liquid, the liquid part can be better applied to farmland, thereby improving the yield and quality of crops and thus improving the breeding efficiency;

In summary, the present invention solves the problems of poor solid-liquid separation effect and inconvenient cleaning of manure solid-liquid separation equipment, and the overall structural design is compact, which greatly improves the efficiency of solid-liquid separation and efficiently utilizes resources, making composting or other treatments more convenient and reducing pollution to the environment.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

Fig. 1 is a schematic diagram of the overall structure of the present invention;

FIG2 is a schematic cross-sectional view of the overall structure of the present invention;

FIG3 is an exploded schematic diagram of FIG2 of the present invention;

FIG4 is a schematic cross-sectional view of the screen drum structure of the present invention;

Serial numbers in the figure: 1. Cylinder; 11. Slag discharge port; 12. Liquid discharge port; 13. Feed port; 14. Fixed ring; 15. Fixed rod; 16. Backwash pump; 17. Backwash pipe; 2. Screen cylinder; 21. Channel steel ring; 22. Gear ring; 23. Baffle ring; 24. Fixed shaft; 25. First spiral blade; 26. Second spiral blade; 27. Third spiral blade; 28. Baffle plate; 29. Tension spring; 3. Fixed ear seat; 31. Horizontal shaft; 32. Servo motor; 33. Driving gear; 34. Flipping blade; 35. Linkage belt; 36. Linkage shaft; 37. Linkage gear.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

Embodiment 1: This embodiment provides a fixed solid-liquid separation device for manure, referring to FIGS. 1-4 , specifically, comprising a cylinder 1, which is a hollow cylinder with a thick middle portion and thin ends, a slag discharge port 11 is provided on the left side of the bottom surface of the cylinder 1, a liquid discharge port 12 is provided in the middle of the bottom surface of the cylinder 1, and a feed port 13 is provided on the right side of the top surface of the cylinder 1;

A screen drum 2 with two ends rotatably connected is provided in the middle of the cylinder 1, and a concentrically distributed fixed shaft 24 is provided in the screen drum 2, and the two ends of the fixed shaft 24 rotatably penetrate the two side walls of the cylinder 1;

A plurality of equally spaced first spiral blades 25 are fixedly disposed on the right side of the fixed shaft 24, a plurality of equally spaced second spiral blades 26 are fixedly disposed on the middle section of the fixed shaft 24, and a plurality of equally spaced third spiral blades 27 are fixedly disposed on the left side of the fixed shaft 24;

The first spiral blades 25 are continuously spirally fixed. Under the spiral action of the first spiral blades 25, the manure liquid is driven into the screen cylinder 2. There are intervals between the second spiral blades 26. The third spiral blades 27 are continuously spirally fixed. Since there are intervals between the second spiral blades 26, the manure liquid is fully squeezed in the screen cylinder 2 and solid-liquid separation is performed.

A pair of fixed ear seats 3 are fixedly provided on the top surface of the cylinder body 1, a fixed shaft 24 is rotatably provided between the tops of the pair of fixed ear seats 3 and is transversely penetrated, a linkage shaft 36 is rotatably provided between the bottoms of the pair of fixed ear seats 3 and is transversely penetrated, and the linkage shaft 36 is connected to the screen cylinder 2 through a meshing assembly.

In the specific implementation process, as shown in FIG3 and FIG4, a rotatably connected baffle plate 28 is sleeved on the left side of the fixed shaft 24, and a tension spring 29 is fixed on the left side of the baffle plate 28. The tension spring 29 is sleeved on the fixed shaft 24, and the left end of the tension spring 29 is fixedly connected to the left side wall of the cylinder 1; under the extrusion of the tension spring 29 and the baffle plate 28, the residue is discharged along the slag discharge port 11;

The meshing assembly includes a gear ring 22 and a linkage gear 37. A pair of concentrically fixed gear rings 22 are sleeved on both sides of the outer ring surface of the screen drum 2. A pair of elliptical through holes are opened on the top surface of the cylinder body 1. A pair of concentrically fixed linkage gears 37 are sleeved on both sides of the linkage shaft 36. Each linkage gear 37 penetrates the corresponding elliptical through hole and is meshed with the gear ring 22. The meshing of the linkage gears 37 drives the gear ring 22 and the screen drum 2 to rotate slowly in the forward direction.

A pair of concentrically fixed driving gears 33 are sleeved on the fixed shaft 24, and each driving gear 33 is meshed and connected with the linkage gear 37 on the corresponding side. The meshing of the driving gear 33 drives the linkage gear 37 and the linkage shaft 36 to rotate in the opposite direction; and the leftmost end of the fixed shaft 24 is coaxially fixed with the motor shaft end of the servo motor 32; the motor shaft of the servo motor 32 drives the horizontal shaft 31, the pair of driving gears 33, a plurality of flap blades 34 and the driving pulley to rotate synchronously;

The right end of the fixed shaft 24 rotates to penetrate the feed port 13 and extends to the outside. A plurality of flapping blades 34 are fixedly arranged on the right side of the fixed shaft 24. The plurality of flapping blades 34 are located in the feed port 13. Under the rotation of the flapping blades 34, the manure and sewage raw liquid enters the right side of the cylinder 1 through the feed port 13.

The right end of the fixed shaft 24 is sleeved with a concentrically fixed driving pulley, and the right end of the fixed shaft 24 is sleeved with a concentrically fixed driven pulley, and the driving pulley is transmission-connected with the driven pulley through a linkage belt 35; the driving pulley drives the driven pulley, the fixed shaft 24, the first spiral blade 25, the second spiral blade 26, and the third spiral blade 27 to rotate synchronously through the linkage belt 35.

It should be noted that: in this embodiment, a pair of concentrically fixed fixing rings 14 are sleeved on both sides of the cylinder 1, and vertically distributed fixing rods 15 are fixed on both sides of the outer ring surface of each fixing ring 14; the fixing rings 14 and the fixing rods 15 play a role in supporting and fixing the cylinder 1;

A pair of symmetrically distributed channel steel rings 21 are fixed at both ends of the screen drum 2, and a pair of channel steel clamping rings are fixed in the middle of the cylinder body 1. Each channel steel ring 21 is rotatably engaged with the corresponding channel steel clamping ring; when the screen drum 2 rotates, the channel steel ring 21 is driven to rotate along the channel steel clamping ring, thereby increasing the rotation stability of the screen drum 2;

A pair of concentrically fixed retaining rings 23 are sleeved on both sides of the screen cylinder 2. The retaining rings 23 are located between the pair of gear rings 22, and the outer ring surface of each retaining ring 23 is rotatably connected to the inner wall of the cylinder body 1; the retaining rings 23 play a role in blocking the contact between the liquid and the gear ring 22.

Embodiment 2: Based on Embodiment 1, this embodiment further includes:

In the specific implementation process, as shown in Figures 2 and 3, a backwash pump 16 is fixedly provided on the left side of the top surface of the cylinder 1, and a pair of backwash pipes 17 are provided at the flushing end of the backwash pump 16. The pair of backwash pipes 17 are distributed on the front and rear sides of the linkage shaft 36. Each backwash pipe 17 is provided with a plurality of backwash nozzles, and each backwash nozzle penetrates the cylinder 1 and faces the screen cylinder 2; under the action of the backwash pump 16, clean water enters the backwash pipe 17 after being pressurized, and the screen cylinder 2 is backwashed and cleaned through the plurality of backwash nozzles.

Specifically, the working principle and operation method of the present invention are as follows:

Step 1, start the servo motor 32, the motor shaft of the servo motor 32 drives the horizontal shaft 31, a pair of driving gears 33, a plurality of flap blades 34 and the driving pulley to rotate synchronously, and the driving pulley drives the driven pulley, the fixed shaft 24, the first spiral blade 25, the second spiral blade 26, and the third spiral blade 27 to rotate synchronously through the linkage belt 35;

Step 2: When the driving gear 33 rotates, the driving gear 33 meshes to drive the linkage gear 37 and the linkage shaft 36 to rotate in the opposite direction, and the linkage gear 37 meshes to drive the gear ring 22 and the screen drum 2 to rotate slowly in the forward direction, so that a certain speed difference is maintained between the fixed shaft 24 and the screen drum 2;

Step 3: Under the rotation of the flip blade 34, the manure liquid enters the right side of the cylinder 1 through the feed port 13, and under the spiral action of the first spiral blade 25, the manure liquid is driven into the screen cylinder 2. Since there is a gap between the second spiral blades 26, the manure liquid is fully squeezed in the screen cylinder 2 and solid-liquid separation is performed;

The separated liquid is discharged through the liquid discharge port 12, and the separated residue is continuously transported under the spiral action of the third spiral blade 27, and is discharged through the residue discharge port 11 under the squeezing action of the tension spring 29 and the baffle plate 28;

Step 4, when the solid-liquid separation of the manure and sewage is completed, the servo motor 32 keeps rotating normally and starts the backwash pump 16. Under the action of the backwash pump 16, the clean water enters the backwash pipe 17 after being pressurized, and the screen drum 2 is backwashed and cleaned through a plurality of backwash nozzles.

The present invention solves the problems of poor solid-liquid separation effect and inconvenient cleaning of manure solid-liquid separation equipment, and the overall structural design is compact, which greatly improves the efficiency of solid-liquid separation and efficiently utilizes resources, making composting or other treatments more convenient and reducing pollution to the environment.

The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims (3)

1. The utility model provides a dirty solid-liquid separation equipment of fixed excrement, includes barrel (1), barrel (1) is the thick hollow tube-shape in middle part both ends, slag notch (11) have been seted up in the bottom surface left side of barrel (1), leakage fluid dram (12) have been seted up in the bottom surface middle part of barrel (1), the top surface right side of barrel (1) is equipped with feed inlet (13), its characterized in that:

the middle part in the cylinder body (1) is provided with a screen cylinder (2) with two end parts connected in a rotating way, the screen cylinder (2) is internally provided with fixed shafts (24) which are concentrically distributed, and the two end parts of the fixed shafts (24) penetrate through the two side walls of the cylinder body (1) in a rotating way;

The right part of the fixed shaft (24) is fixedly provided with a plurality of first spiral blades (25) which are distributed at equal intervals, the middle part of the fixed shaft (24) is fixedly provided with a plurality of second spiral blades (26) which are distributed at equal intervals, and the left part of the fixed shaft (24) is fixedly provided with a plurality of third spiral blades (27) which are distributed at equal intervals;

the first spiral blades (25) are continuously and spirally fixedly connected, the second spiral blades (26) are respectively provided with a space, and the third spiral blades (27) are continuously and spirally fixedly connected;

The top surface of the cylinder body (1) is fixedly provided with a pair of fixed lug seats (3), a pair of fixed shafts (24) which transversely penetrate through the fixed lug seats are rotatably arranged between the tops of the fixed lug seats (3), a pair of linkage shafts (36) which transversely penetrate through the fixed lug seats are rotatably arranged between the bottoms of the fixed lug seats (3), and the linkage shafts (36) are connected with the screen cylinder (2) through meshing components;

A pair of concentric fixed rings (14) are sleeved on two sides of the cylinder body (1), and fixing rods (15) which are vertically distributed are fixedly arranged on the front side and the rear side of the outer ring surface of each fixed ring (14);

two end parts of the screen cylinder (2) are fixedly provided with symmetrically distributed channel steel rings (21), a pair of channel steel snap rings are fixedly arranged in the middle part of the cylinder body (1), and each channel steel ring (21) is rotationally clamped on the corresponding channel steel snap ring;

a baffle disc (28) which is rotationally connected is sleeved on the left side of the fixed shaft (24), a tension spring (29) is fixedly arranged on the left side surface of the baffle disc (28), the tension spring (29) is sleeved on the fixed shaft (24), and the left end part of the tension spring (29) is fixedly connected with the left side wall in the cylinder body (1);

a pair of baffle rings (23) which are concentrically and fixedly connected are sleeved on two sides of the screen cylinder (2), the pair of baffle rings (23) are positioned between the pair of gear rings (22), and the outer ring surface of each baffle ring (23) is rotationally connected with the inner wall of the cylinder body (1);

The meshing assembly comprises gear rings (22) and linkage gears (37), a pair of concentric fixedly connected gear rings (22) are sleeved on two sides of the outer ring surface of the screen drum (2), a pair of elliptical through holes are formed in the top surface of the drum body (1), a pair of concentric fixedly connected linkage gears (37) are sleeved on two sides of the linkage shaft (36), and each linkage gear (37) penetrates through the corresponding elliptical through hole and is in meshing connection with the gear ring (22);

A pair of driving gears (33) which are concentrically fixedly connected are sleeved on the fixed shaft (24), each driving gear (33) is meshed and connected with a corresponding one-side linkage gear (37), and the leftmost end part of the fixed shaft (24) is coaxially fixedly connected with the end part of a motor shaft of the servo motor (32);

The right end part of the fixed shaft (24) rotates to penetrate through the feed inlet (13) and extends to the outer side, a plurality of turning blades (34) are fixedly arranged on the right side of the fixed shaft (24), and the turning blades (34) are positioned in the feed inlet (13);

the right end part of the fixed shaft (24) is sleeved with a driving belt pulley which is concentrically fixedly connected, the right end part of the fixed shaft (24) is sleeved with a driven belt pulley which is concentrically fixedly connected, and the driving belt pulley is in transmission connection with the driven belt pulley through a linkage belt (35).

2. The stationary fecal sewage solid-liquid separation device according to claim 1, characterized in that: the back flush pump (16) is fixedly arranged on the left side of the top surface of the cylinder body (1), a pair of back flush pipes (17) are respectively arranged at the flushing end of the back flush pump (16), the back flush pipes (17) are distributed on the front side and the back side of the universal driving shaft (36), a plurality of back flush spray heads are arranged on each back flush pipe (17), and each back flush spray head penetrates through the cylinder body (1) and faces the screen cylinder (2).

3. The separation method of a stationary fecal sewage solid-liquid separation device according to claim 2, characterized by comprising the steps of:

Step one, starting a servo motor (32), wherein a motor shaft of the servo motor (32) drives a cross shaft (31), a pair of driving gears (33), a plurality of turning blades (34) and a driving belt pulley to synchronously rotate, and the driving belt pulley drives a driven belt pulley, a fixed shaft (24), a first helical blade (25), a second helical blade (26) and a third helical blade (27) to synchronously rotate through a linkage belt (35);

Step two, when the driving gear (33) rotates, the driving gear (33) is meshed to drive the linkage gear (37) and the linkage shaft (36) to rotate reversely, and the linkage gear (37) is meshed to drive the gear ring (22) and the screen drum (2) to rotate slowly and positively, so that a certain rotation speed difference is kept between the fixed shaft (24) and the screen drum (2);

under the rotation action of the turning blades (34), the fecal sewage stock solution enters the right side in the cylinder (1) through the feed inlet (13), and under the spiral action of the first spiral blades (25), the fecal sewage stock solution is driven to enter the screen cylinder (2), and as a plurality of second spiral blades (26) are provided with intervals, the fecal sewage stock solution is fully extruded in the screen cylinder (2) and subjected to solid-liquid separation;

The separated liquid is discharged along the liquid discharge port (12), the separated residues are continuously conveyed under the spiral action of the third spiral blade (27), and the residues are discharged along the slag discharge port (11) under the extrusion action of the tension spring (29) and the baffle disc (28);

And fourthly, after solid-liquid separation of the fecal sewage raw liquid is completed, the servo motor (32) keeps normal rotation, the back flush pump (16) is started, clear water enters the back flush pipe (17) after being pressurized under the action of the back flush pump (16), and back flush cleaning is carried out on the screen cylinder (2) through a plurality of back flush spray heads.