JP7372869B2 - suction car - Google Patents

Description

The present invention relates to a suction wheel equipped with a water ring pump that generates a flow of air by pressurizing and depressurizing the internal air of a receiver tank that collects objects to be collected.

Conventionally, construction sites, sewage treatment plants, etc. have been equipped with a suction device that collects objects to be recovered, such as sludge, earth and sand, and waste liquid, into a receiver tank, and the collected objects are transported to a predetermined location such as a treatment plant. Suction cars are known. For example, a suction device equipped with a water ring pump is known as disclosed in Patent Document 1.

Japanese Patent Application Publication No. 2003-237906

For example, as shown in FIG. 6, in a general water ring pump 125, when water is poured into a cylindrical casing 101 and the impeller 102 is rotated eccentrically, the seal water is pumped inside the casing 101 by centrifugal force. The water flows as if pressed against the cylindrical wall, forming a water return 103, and a space with a crescent-shaped cross section is created at the inner circumference of the water reflux 103. In this space, an independent air chamber formed by two adjacent blades and the inner surface of the water return 103 repeats expansion and contraction as the impeller 102 rotates, so the appropriate position on the side of this air chamber is By opening the intake port 104 and the exhaust port 105, it becomes possible to continuously rotate the reciprocating suction machine using the water return 103 as a piston. In other words, the water ring pump 125 is a pump that generates negative pressure by rotating water in an annular manner. Since water forms part of the pump, it has many advantages, such as being clean, quiet, having no metal contact, and requiring no oil. It also has the following characteristics: ``There is a large gap between the impeller 102 and the casing 101, so it is resistant to foreign objects'' and ``It does not operate as a pump when the water runs out, so it is less likely to seize.''

However, in this type of water ring pump 125, the space inside the pump is filled with vapor (steam that has become a gas) in which the seal water has evaporated, so the characteristics in a high vacuum region depend on the suction gas temperature and the seal. Affected by vapor pressure, which changes with water temperature. Therefore, there is a problem in that the negative pressure decreases as the temperature of the sealed water increases.

The present invention has been made in view of this point, and its purpose is to prevent negative pressure from decreasing as the seal water becomes hotter in a water ring pump.

In order to achieve the above object, the present invention is equipped with an ejector device that can utilize air from an on-vehicle air tank.

Specifically, in the first invention, a receiver tank that collects objects to be collected;
The present invention is directed to a suction wheel equipped with a water ring pump that pressurizes and depressurizes the internal air of the receiver tank to generate an air flow.

And in the above suction wheel,
A pipe connecting the receiver tank and the water ring pump is provided with an ejector that introduces air at a higher pressure than the upstream side of the pipe as driving air.

Here, "to be interposed" means to be provided between members. "Air" is a concept that includes air.

According to the above configuration, by providing the ejector, air at a higher pressure than the upstream side of the piping, such as atmospheric air, is introduced into the piping, which is under negative pressure due to the water ring pump, and the air is jetted out at high speed. The surrounding area is further depressurized. Furthermore, since air is introduced into the pump body at a higher pressure than the upstream side of the piping, cavitation is less likely to occur. Furthermore, by introducing air with a higher pressure than the upstream side of the piping, such as the atmosphere, it is possible to expect the effect of reducing the sealing water temperature, and it is possible to suppress a decrease in suction performance during continuous operation.

In the second invention, in the first invention,
The driving air is configured to be supplied from an on-vehicle air tank through driving air piping.

Here, "driving air can be supplied from the on-vehicle air tank through the driving air piping" does not mean that it is always supplied from the air tank through the driving air piping, but means that it can be supplied when necessary.

According to the above configuration, when the differential pressure between the atmosphere and the receiver tank is small, such as when the water ring pump is operated, the water ring pump does not generate much heat, so even if atmospheric pressure is used, the cooling capacity is not sufficient. I can demonstrate it. On the other hand, as negative pressure increases, the load on the water ring pump increases, heat generation increases, and the water temperature tends to rise. Therefore, when the pressurized air from the air tank is sent into the water seal pump, the temperature of the air decreases when the pressurized air expands and the pressure decreases, making it possible to suppress the rise in the seal water temperature.

In the third invention, in the second invention,
The air tank stores pressurized air used when braking the vehicle.

According to the above configuration, pressurized air from the vehicle braking air tank installed as standard equipment can be used as driving air, and there is no need to provide a separate air tank for the water ring pump. Normally, the vehicle does not run during suction work, so there is no problem with running even if the air tank is also used for vehicle braking.

In the fourth invention, in the third invention,
A stop valve is provided in the driving air piping connecting the ejector and the air tank to stop the supply of driving air to the ejector when the vehicle is running.

According to the above configuration, pressurized air is not supplied from the air tank to the ejector by the stop valve, so that the vehicle braking operation by the air tank is not inhibited when the vehicle is running.

In a fifth invention, in any one of the second to fourth inventions,
A drive air switching valve is interposed in the drive air piping, and an external air introduction pipe that communicates with the outside of the vehicle is connected to the drive air switching valve.By switching the drive air switching valve, the drive air It is configured such that the air can be switched to either pressurized air from the air tank or external air from the external air introduction pipe.

According to the above configuration, by normally introducing external air from the external air introduction pipe and using pressurized air from the air tank only when necessary, it is possible to avoid running out of pressurized air in the air tank.

In the sixth invention, in the fifth invention,
The driving air switching valve is configured to automatically switch between the pressurized air and the external air at a predetermined set pressure.

According to the above configuration, when the differential pressure between the inside of the receiver tank and the atmosphere is small, the drive air switching valve is switched to take in external air. On the other hand, when the negative pressure inside the receiver tank increases, the air inside the receiver tank becomes diluted and the water ring pump cannot take in enough air. Then, when the negative pressure becomes higher than the predetermined pressure, the drive air switching valve is automatically switched to the pressurized air side. By doing so, when the air in the receiver tank becomes thin, the pressurized air from the air tank is sent into the water ring pump, increasing the negative pressure effect due to the ejector effect, while ensuring that sufficient air is supplied to the water ring pump. , enabling stable operation. At the same time, the rise in water temperature can be suppressed.

As explained above, according to the present invention, air having a higher pressure than the upstream side of the piping connecting the receiver tank and the water ring pump is introduced into the water ring pump as driving air using an ejector. , it is possible to prevent negative pressure from decreasing while preventing the sealed water from becoming high temperature.

It is a figure explaining the flow of air including a water ring type pump at the time of suction. It is a figure explaining the flow of air including a water ring type pump at the time of pressurization. FIG. 1 is a side view showing a suction wheel having a water ring pump according to an embodiment of the present invention. FIG. 1 is a plan view showing a suction wheel having a water ring pump according to an embodiment of the present invention. It is a pneumatic circuit diagram showing the flow of air from an air tank to an ejector. It is a side view which expands and shows an operation panel. It is a sectional view for explaining operation of a water ring type pump.

Embodiments of the present invention will be described below based on the drawings.

2 and 3 show a suction wheel 2 according to an embodiment of the present invention, and a suction device 1 is provided on a subframe 4 on a chassis 3 of this suction wheel 2.

Specifically, a receiver tank 5 is mounted at the rear of the subframe 4 to collect objects to be collected, such as sludge, earth and sand, waste liquid, and the like. The receiver tank 5 includes, for example, a tank body 5a having a circular cross-sectional container shape and a rear end opening, and a tail gate 5c that opens and closes the rear end opening. The tailgate 5c is rotatably supported, for example, at the upper rear end of the tank body 5a via a hinge pin 5b. An opening/closing cylinder 5d is provided between the tank body 5a and the tailgate 5c, and by expanding and contracting the opening/closing cylinder 5d, the tailgate 5c can open and close the rear end opening of the tank body 5a. There is.

At the bottom of the tailgate 5c, there are provided a suction port 8 with an on-off valve that serves as a suction port for objects to be collected, and a discharge port 9 with an on-off valve that serves as an outlet for discharging objects to be collected.

The receiver tank 5 is pivotally supported so as to be tiltable relative to the subframe 4 via a tilting shaft 10 provided at the rear of the subframe 4. That is, a tilting cylinder 11 is provided between the subframe 4 and the receiver tank 5. By expanding and contracting the tilting cylinder 11, the receiver tank 5 is rotated to stand up or to fall down around the tilting shaft 10.

As will be described in detail later, when the suction device 1 sucks and collects the object into the receiver tank 5, due to the reduced pressure inside the receiver tank 5 and the flow of air, the object is removed from the outside through a suction hose (not shown) connected to the suction port 8. The object to be collected is sucked into the receiver tank 5. On the other hand, when the suction device 1 discharges the material to be recovered in the receiver tank 5 to a sludge treatment plant, for example, the air in the receiver tank 5 is pressurized and the air inside the receiver tank 5 is pumped through a discharge hose (not shown) connected to the discharge port 9. The collected materials are discharged outside. Furthermore, by opening the tailgate 5c and rotating the receiver tank 5 in an upright position, it is also possible to discharge the objects to be collected in the receiver tank 5.

Furthermore, a water ring pump 25 is provided on the subframe 4 between the driver's cab 13 and the receiver tank 5 to increase and decrease the pressure of the air in the receiver tank 5 to generate an air flow. Although not shown in detail, the water ring pump 25 is rotatably driven by the driving force of an engine (not shown) connected to the PTO drive shaft of the suction wheel 2. Arranged around the water ring pump 25 are piping connected to the water ring pump 25, various valves, an operation panel 15, and the like.

As shown in FIGS. 1A and 1B, the suction device 1 includes a receiver tank 5 as a primary catcher, a secondary catcher 20 and a tertiary catcher 21 consisting of a cyclone, and a quaternary catcher 22 consisting of a steam/water separator and water tank. etc. are connected via piping made of metal round steel pipes, etc. In this embodiment, a tertiary catcher 21, a quaternary catcher 22, and an integrated silencer 23 are provided integrally. These devices are connected by a receiver tank pressurization/depressurization pipe 7.

The receiver tank 5 is connected to the secondary catcher 20 by a first pipe 7a. Further, the secondary catcher 20 is connected to the tertiary catcher 21 by a second pipe 7b.

The water ring pump 25, the tertiary catcher 21, the quaternary catcher 22, and the integrated silencer 23 are connected to an air switching type four-way valve 24 via piping. Specifically, the tertiary catcher 21 and the air switching type four-way valve 24 are connected by the third pipe 7c. Further, the water ring pump 25 and the air switching type four-way valve 24 are connected by a fourth pipe 7d. Further, the quaternary catcher 22 and the air switching type four-way valve 24 are connected by a fifth pipe 7e. Further, the integrated silencer 23 and the air switching type four-way valve 24 are connected by a sixth pipe 7f. During suction, the tertiary catcher 21 and water ring pump 25 are connected via the air switching type four-way valve 24, while the quaternary catcher 22, integrated silencer 23, and air switching type are connected via the four-way valve 24. It is now possible to do so. Furthermore, by switching the air switching type four-way valve 24, during pressurization, the integrated silencer 23 and the water ring pump 25 are connected via the air switching type four-way valve 24, while the quaternary catcher 22 and the tertiary The catcher 21 is connected via an air switching type four-way valve 24.

The water ring pump 25 has a suction port 25a and a discharge port 25b. The discharge port 25b is connected to the quaternary catcher 22 by a seventh pipe 7g.

As a feature of the present invention, an ejector 30 is provided in the pipe connecting the receiver tank 5 and the water ring pump 25 to introduce air at a higher pressure than the upstream side of the pipe as driving air. Specifically, the ejector 30 is interposed in the fourth pipe 7d between the air switching type four-way valve 24 and the water ring type pump 25. Note that the fourth pipe 7d may be provided with a bypass passage (not shown) that passes from the air switching type four-way valve 24 to the suction port 25a without passing through the ejector 30.

An upstream large diameter cylindrical part 30a, a gradually reduced diameter cylindrical part 30b connected to the upstream large diameter cylindrical part 30a, a small diameter cylindrical part 30c connected to the gradually reduced diameter cylindrical part 30b, and a small diameter cylindrical part 30c. a downstream large-diameter cylinder part 30e connected to the gradual diameter-expanding cylinder part 30d, and an upstream cylinder part 30b so as to eject driving air toward The nozzle portion 30f is provided at the center of the inside of the side large diameter cylindrical portion 30a. The upstream large diameter cylindrical part 30a, the gradually decreasing diameter cylindrical part 30b, the small diameter cylindrical part 30c, the gradually increasing diameter cylindrical part 30d, the downstream large diameter cylindrical part 30e, and the nozzle part 30f each pass through the same linear center line CL. It is formed like this. The upstream large diameter cylindrical portion 30a and the downstream large diameter cylindrical portion 30e have the same diameter. Further, the downstream large diameter cylindrical portion 30e is connected to a suction port 25a provided on the upper surface side of the water ring pump 25. As a result, the ejector 30 is erected on the upper surface side of the water ring pump 25.

As shown in FIG. 4, the driving air of the ejector 30 is configured to be able to be supplied to the nozzle portion 30f of the ejector 30 from an on-vehicle air tank 41 through a driving air piping 60. In this embodiment, the air tank 41 is provided on the vehicle chassis 3 side and stores pressurized air used when braking the vehicle.

Specifically, this driving air piping 60 will be explained using FIG. 4. The driving air piping 60 includes a first driving air piping 60a for supplying driving air from the air tank 41 to the nozzle portion 30f, and a first driving air piping 60a that branches off toward the air switching type four-way valve 24. It has a second driving air pipe 60b for supplying driving air. A protection valve 42, a ball valve 43, a stop valve 44, and a drive air switching valve 49 are interposed in the first drive air piping 60a in order from the one closest to the upstream air tank 41.

For example, pressurized air of 0.7 MPa is supplied from the air tank 41. The protection valve 42 prevents any further air leakage when air leakage occurs in the drive air piping 60.

For example, the ball valve 43 can be manually switched so as not to supply air from the air tank 41 to the bodywork side (suction device 1 side).

The stop valve 44 is provided to stop the supply of drive air to the ejector 30 when the vehicle is running. This stop valve 44 is composed of a solenoid valve, and is configured to operate in conjunction with a PTO switch (not shown) under the control of a bodywork control section (not shown). The PTO switch is a switch that extracts the driving force from the vehicle's driving engine (not shown) to enable the water ring pump 25 to be driven. When this PTO switch is on, it communicates with the air tank 41 side, and when the PTO switch is off, it is switched to the silencer 53 side.

In this embodiment, since the PTO switch is off when the vehicle is running, pressurized air is not supplied from the air tank 41 to the ejector 30 by the stop valve 44, so that the vehicle braking operation by the air tank 41 is not inhibited. .

The drive air switching valve 49 allows the drive air to be switched to either pressurized air from the air tank 41 or external air from the external air introduction pipe 50. This drive air switching valve 49 is connected to an external air introduction pipe 50 that communicates with the outside of the vehicle. For example, the driving air switching valve 49 is configured to automatically switch between pressurized air and external air at a predetermined set pressure.

The drive air switching valve 49 is operated in three modes by a changeover switch 15d (see FIG. 5) provided on the operation panel 15. These three modes are a mode in which pressurized air from the air tank 41 is manually supplied to the ejector 30, a mode in which external air is manually supplied to the ejector 30, and a mode in which external air is supplied to the ejector 30 when suction is started. The mode is such that when the negative pressure increases, pressurized air from the air tank 41 is automatically supplied to the ejector 30 after reaching a predetermined set value.

Further, between the stop valve 44 and the drive air switching valve 49, a second drive air pipe 60b is branched from the first drive air pipe 60a.

A four-way switching valve unit 51 is provided in the second driving air piping 60b via a check valve 45 that prevents backflow of air to the air tank 41 side. The air switching type four-way valve 24 is connected to the downstream side of the four-way valve switching valve unit 51. The four-way valve switching valve unit 51 is switched and controlled by the bodywork control section based on pressing any one of the suction button 15a, the neutralization button 15b, and the pressure button 15c provided on the operation panel 15 shown in FIG. be done.

- Operation of suction device -
Next, the operation of the suction device will be explained using the drawings.

First, with the suction wheel 2 stopped running, a PTO switch provided in the driver's cab 13 or the like is turned on. Then, the driving force of the engine for driving the vehicle is supplied to the water ring pump 25. Furthermore, under the control of the bodywork control section, the stop valve 44 is switched to the side communicating with the air tank 41.

Next, the operator presses the suction button 15a on the operation panel 15 to start suction. Then, the spool of the air switching type four-way valve 24 moves to the suction side due to the pressure of the pressurized air in the air tank 41.

Next, the air switching type four-way valve 24 is switched to the state shown in FIG. 1A, and the water ring type pump 25 is driven, air is sucked in from the suction port 8, and the object to be collected is collected into the receiver tank 5. Air passes through the receiver tank 5, the secondary catcher 20, and the tertiary catcher 21, passes through the air switching type four-way valve 24, and is sucked in from the suction port 25a of the water ring pump 25. At this time, air from the air switching type four-way valve 24 passes through the ejector 30.

At the start of suction, the negative pressure inside the receiver tank 5 has not increased above the predetermined value (the pressure is above the predetermined value), so the drive air switching valve 49 is on the external air side, and the external air introduction pipe 50 External air (atmosphere) is sucked in through the silencer 53. As a result, the atmosphere is introduced into the ejector 30. In this way, when the differential pressure between the atmosphere and the inside of the receiver tank 5 is small, such as when the water ring pump 25 is driven, the water ring pump 25 does not easily generate heat, so even if atmospheric pressure is used, the cooling capacity is not sufficient. can be demonstrated. Since external air having a lower temperature than the seal water is sent to the water ring pump 25, the temperature rise of the water ring pump 25 and the seal water is suppressed.

On the other hand, when the negative pressure inside the receiver tank 5 increases, the load on the water ring pump 25 increases, heat generation increases, and the water temperature tends to rise. As the negative pressure increases, the sealed water becomes more likely to evaporate, making cavitation more likely to occur. Therefore, when the negative pressure in the receiver tank 5 rises above a predetermined value, a signal is sent to the drive air switching valve 49 to switch from the external air side to the pressurized air side.

Then, the pressurized air in the air tank 41 is sent to the ejector 30. By sending this pressurized air into the water ring pump 25, the negative pressure within the receiver tank 5 is further increased due to the ejector effect. Further, a large amount of air is supplied to the water ring pump 25 from the nozzle portion 30f. The temperature of the pressurized air ejected from the nozzle portion 30f decreases when it expands and its pressure decreases, so a large amount of cold air is supplied to the water ring pump 25. This makes it possible to suppress an increase in the temperature of the seal water in the water ring pump 25, and eliminates concerns about cavitation.

The air sucked into the water ring pump 25 is discharged from the discharge port 25b, passes through the quaternary catcher 22, returns to the air switching type four-way valve 24, passes through the integrated silencer 23, and is exhausted to the outside.

On the other hand, when switching from suction to centering, the operator presses the centering button 15b on the operation panel 15. Then, the spool of the air switching type four-way valve 24 returns to the center side due to the pressure of the pressurized air in the air tank 41.

When switching from medium pressure to pressure, the operator presses the pressure button 15c on the operation panel 15. Then, the spool of the air switching type four-way valve 24 moves from the center side to the pressurizing side due to the pressure of the pressurized air in the air tank 41.

Next, the air switching type four-way valve 24 is switched to the state shown in FIG. It passes through the four-way valve 24, passes through the tertiary catcher 21 and the secondary catcher 20, reaches the receiver tank 5, and is discharged from the discharge port 9 together with the recovered object.

As explained above, by providing the ejector 30, air at a higher pressure than the upstream side of the piping, such as the atmosphere, is introduced into the piping, which is under negative pressure due to the water ring pump 25, and the air is ejected at high speed. This further reduces the pressure in the surrounding area. Furthermore, since air is introduced into the pump body at a higher pressure than the upstream side of the piping, cavitation is less likely to occur. Furthermore, by introducing air at a lower temperature and higher pressure than the air on the upstream side of the piping, an effect of lowering the sealing water temperature can be expected, and a decrease in suction performance during continuous operation can be suppressed.

In this embodiment, the conventionally installed air tank 41 may be used, and there is no need to provide a separate air tank 41 for the water ring pump 25. Normally, the vehicle does not run during suction work, so there is no problem in running even if the air tank 41 for braking the vehicle is also used.

In this embodiment, by using the pressurized air from the air tank 41 only when necessary, it is possible to avoid running out of pressurized air in the air tank 41.

Therefore, according to the suction wheel 2 according to the present embodiment, the ejector 30 uses external air or pressurized air with a higher pressure than the upstream side of the pipe connecting the receiver tank 5 and the water ring pump 25 as driving air to seal the water seal. By introducing it into the type pump 25, it is possible to prevent the negative pressure from decreasing as the temperature of the sealed water increases.

Note that the above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its applications, or uses.

For example, in the above embodiment, the pressurized air supplied to the ejector 30 is supplied using the air tank 41 for vehicle braking, but the present invention is not limited to this. Pressurized air may be supplied to the ejector from a pressure tank.

1 Suction device
2 Suction wheel
3 Chassis
4 Subframe
5 Receiver tank
5a Tank body
5b Hinge pin
5c tailgate
5d Open/close cylinder
7 Receiver tank pressure reduction piping
8 Suction port
9 Outlet
10 Tilt axis
11 Tilt cylinder
13 Driver's Cab
15 Operation panel
15a Suction button
15b Center button
15c Pressure button
15d Changeover switch
20 Secondary catcher
21 Tertiary catcher
22 4th catcher
23 Integrated silencer
24 Air switching type four-way valve
25 Water ring pump
25a Suction port
25b Discharge port
30 Ejector
30a Upstream large diameter cylindrical part
30b Gradually reduced diameter cylinder part
30c Small diameter cylindrical part
30d Gradually expanding diameter tube part
30e Downstream large diameter cylindrical part
30f nozzle part
41 Air tank
42 Protection valve
43 Ball valve
44 Stop valve
45 Check valve
49 Drive air switching valve
50 External air introduction pipe
51 Four-way valve switching valve unit
53 Silencer
60 Piping for driving air
60a First drive air piping
60b Second driving air piping 101 Casing 102 Impeller 103 Water recirculation 104 Intake port 105 Exhaust port CL Center line

Claims (5)

a receiver tank for collecting objects to be collected;
A suction vehicle equipped with a water ring pump that pressurizes and depressurizes the internal air of the receiver tank to generate an air flow,
A pipe connecting the receiver tank and the water ring pump is provided with an ejector that introduces air at a higher pressure than the upstream side of the pipe as driving air,
The above driving air is configured so that it can be supplied from the on-board air tank through the driving air piping.
A suction vehicle characterized by: The suction wheel according to claim 1 ,
The suction vehicle is characterized in that the air tank stores pressurized air used during vehicle braking. The suction wheel according to claim 2 ,
The suction vehicle is characterized in that the drive air piping connecting the ejector and the air tank is provided with a stop valve for stopping the supply of drive air to the ejector when the vehicle is running. The suction wheel according to any one of claims 1 to 3 ,
A drive air switching valve is installed in the drive air piping.
An external air introduction pipe communicating with the outside of the vehicle is connected to the drive air switching valve,
The suction vehicle is characterized in that the drive air can be switched to either pressurized air from the air tank or external air from the external air introduction pipe by switching the drive air switching valve. . The suction wheel according to claim 4 ,
The suction wheel is characterized in that the driving air switching valve is configured to automatically switch between the pressurized air and the external air at a predetermined set pressure.

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