EP2299002A1

EP2299002A1 - Method for warming a nozzle of a spraying system

Info

Publication number: EP2299002A1
Application number: EP09170845A
Authority: EP
Inventors: Esa Tuominen; Ilmari Sikander
Original assignee: Destia Oy
Current assignee: Destia Oy
Priority date: 2009-09-21
Filing date: 2009-09-21
Publication date: 2011-03-23

Abstract

A method for warming nozzles (13,20-25,31) that sprinkle anti-freeze agent to be sprayed on a road surface, by installing warming elements (30) in the immediate proximity of each nozzle (13,20-25,31) and by controlling the warming elements intelligently and anticipatorily. A number of weather parameters may be measured, and history data of the measured weather data and the apparatus use data may be stored in a control logic (16). The warming of the nozzles is stopped when a limit condition is fulfilled.

Description

FIELD OF THE INVENTION

The invention relates to an automatic anti-skid treatment, specifically for keeping road surfaces unfrozen, by applying an anti-freeze agent, and to ensuring the reliability of the apparatus in different weather conditions.

BACKGROUND OF THE INVENTION

Ensuring road surface safety with the changing weather and temperature conditions is an essential problem in road traffic. In particular, freezing of the road surfaces reduces significantly the friction between the tires and the road surface. The grip of the tires may be improved not only by the properties of the tires and by selecting the driving style, but also by ensuring that the road surface stays unfrozen. Typically, in the Nordic winter conditions this has been carried out by applying suitable salt or brine on the road surface when the temperature threatens to sink below zero. The brine lowers the freezing point of water below the normal freezing point (for about ten degrees at the best) so that the road surface will not freeze that easily. The solution has traditionally been applied by specific brining vehicles.
The ice-control salt which is typically sodium chloride is not very environmentally friendly. Therefore, other agents such as potassium formiate have been introduced.
Anti-freeze agent may also be sprayed on the road by specific nozzles installed fixedly to the road or the shoulder. The drawback of this arrangement is the high cost, which is why it is most appropriately realized at specific carefully selected sites where it is particularly desirable to prevent skidding.
A main problem with the nozzles that spray anti-freeze agent is that the opening may freeze over, which makes the nozzle inoperative. In the prior art, steps have been taken to solve this problem for example by fabricating the nozzles to be more water-proof so that the parts inside the nozzle body would not contact water. One such idea has been described in patent publication US 2005/0072859 .
Publication EP 981050776 (Boschung et al. ) describes a spraying apparatus for a wetting agent to apply brine on the surface of traffic roads. Boschung employs a large number of fixedly mountable spraying elements so as to spray brine in fine distribution, wherein the volume flow per nozzle is defined relatively low, about 1.5 to 8 ml per second. Boschung concentrates mainly on the dimensions of the inside diameters of the spray pipes, of the distances between the nozzles, as well as of the number of nozzles per road surface area to be covered.
A basic problem in an apparatus that sprays anti-freeze agent on a road surface is consequently that, in a typical use situation, the nozzles are subject to freezing and must be maintained unfrozen, and thereby operational, in some cost-effective manner.

OBJECTIVE OF THE INVENTION

The objective of the invention is to disclose a method and an apparatus for warming the nozzles of a spraying system as well as a method for intelligent controlling of the warming. Specifically, the objective of the invention is to alleviate the problems referred to above.

SUMMARY OF THE INVENTION

The present invention discloses a method for warming a nozzle in a fluid spraying apparatus comprising at least one nozzle, a fluid container, a pipeline between the fluid container and the nozzles, and control logic for the apparatus. The method is characterized in that it comprises the steps of:

measuring at least one of the following parameters: quantity of ice in aqueous solution, outside-air temperature, temperature of the monitored surface, temperature of the nozzles, atmospheric humidity, strength of wind, intensity and type of precipitation, image of the monitored surface;
warming at least one of the nozzles by a warming element when a desired warming switch-on limit condition is fulfilled, wherein the switch-on limit condition is defined by at least one measured parameter; and
stopping the warming of the warmed nozzle when a desired warming switch-off limit condition is fulfilled, wherein the switch-off limit condition is defined by at least one measured parameter.

In one embodiment of the present invention, the monitored surface is a traffic way and the agent to be sprayed is an anti-freeze agent.
In one embodiment of the present invention, said parameters are re-measured when the nozzle is being warmed and before the warming of the nozzle is stopped.
In one embodiment of the present invention, an image of the monitored surface is established in advance when the surface is dry and unfrozen;
an image of the monitored surface is established at the time of observation; and
the possible presence of water and/or ice on the surface is determined by the change in said images, which information is transferred to the control logic.
In one embodiment of the present invention, the measured parameters and status data about the apparatus are collected to a control logic server; and
an alarm is sent to an external control room if any part of the apparatus is damaged or if the conditions on the monitored surface become dangerous.
In one embodiment of the present invention, said warming element is a self-adjusting warming cable installed as a coil in the immediate proximity of the nozzle.
In one embodiment of the present invention, said warming element is a thermal resistance installed in the immediate proximity of the nozzle.
In one embodiment of the present invention, the method further comprises the steps of:

monitoring the variation trend of the parameters as a function of time;
supplying a current weather report to the control logic; and
determining the need of warming the nozzles based on the parameters, the variation trend thereof and the weather report.

In one embodiment of the present invention, warming of each nozzle is controlled separately and as a function of time to operate either non-recurrently or to be switched on in pulses.
In one embodiment of the present invention, the measurement parameters and the apparatus use parameters are collected in a log file; and
the log file data is utilized to optimize the use of the warming elements.
According to a second aspect of the present invention, a system for warming a nozzle in a fluid spraying apparatus is disclosed, wherein the system comprises at least one nozzle, a fluid container, and a pipeline between the fluid container and the nozzles.
The system is characterized in that it further comprises:

sensors for measuring at least one of the following parameters: quantity of ice in aqueous solution, outside-air temperature, temperature of the monitored surface, temperature of the nozzles, atmospheric humidity, strength of wind, intensity and type of precipitation, image of the monitored surface;
a technical room including a processor, control logic of the apparatus and a memory unit;
at least one warming element for respectively warming at least one nozzle when a desired warming switch-on limit condition is fulfilled, wherein the switch-on limit condition is defined by at least one measured parameter; and
for stopping the warming of the warmed nozzle when a desired warming switch-off limit condition is fulfilled, wherein the switch-off limit condition is defined by at least one measured parameter.

In one embodiment of the present invention, the system further comprises a control room which can be contacted from the technical room to transfer the measurement parameters and control commands between them.
In one embodiment of the present invention, the system further comprises a separate weather station arranged to measure the above-mentioned parameters continuously or at the desired times.
In one embodiment of the present invention, the system further comprises at least one camera for taking an image of the monitored surface at the desired times, wherein the received image signal is in the range of a desired frequency band.
According to a third aspect of the present invention, the inventive idea further comprises a computer program for controlling the warming of a nozzle in a fluid spraying apparatus comprising at least one nozzle, a fluid container, a pipeline between the fluid container and the nozzles, and control logic of the apparatus. The computer program comprises program code which, when run on a data-processing device, has been arranged to execute the steps of:

controlling a measurement of at least one of the following parameters: quantity of ice in aqueous solution, outside-air temperature, temperature of the monitored surface, temperature of the nozzles, atmospheric humidity, strength of wind, intensity and type of precipitation, image of the monitored surface;
commanding a warming of at least one nozzle performed by at least one warming element to be activated when a desired warming switch-on limit condition is fulfilled, wherein the switch-on limit condition is defined by at least one measured parameter; and
commanding the warming of the warmed nozzle to be stopped when a desired warming switch-off limit condition is fulfilled, wherein the switch-off limit condition is defined by at least one measured parameter.

The advantage of the present invention is that it allows one ensure intelligently, anticipatorily and automatically that the nozzles of an apparatus that sprays anti-freeze agent stay unfrozen in all weather conditions, optimizing the energy consumption as well. This has not been accomplished in any prior art solutions.

LIST OF FIGURES

Fig. 1 presents an example of a system and apparatus according to the invention,
Fig. 2 presents a nozzle used in the invention as seen from different directions, and
Fig. 3 presents an arrangement used in the invention for warming a nozzle.

DETAILED DESCRIPTION OF THE INVENTION

The present invention discloses a new manner for ensuring the reliability of a spraying system that applies anti-freeze agent in different temperature conditions. The idea is to disclose an energy-efficient and reliable manner of keeping the nozzles in the spraying system unfrozen and operational.
The apparatus of the invention is illustrated in Fig. 1. A weather station 10 may be disposed at a suitable site on the roadside, containing devices which monitor the road surface and the weather. The weather station 10 may include a camera, a thermometer for the temperature of the road surface and the air, a hygrometer to determine the dew point, an anemometer and a precipitation gauge, or only some of these measuring devices. In the examples of the invention, a camera refers broadly to a device which is able to receive information over different wavelength ranges and, where necessary, over other than the visible light range. This device allows one to monitor the color of the road surface over the selected frequency bands so as to be able to detect water or ice on the road surface. So-called dry calibration may be performed in advance to determine the color of the road surface for example in a dry cold weather during daylight. By measuring, at each time of observation, the difference between the color of the road surface and the reference color from the calibration over the suitably selected frequency bands it can be determined when there is water or ice on the road surface. Since the reflective properties of water and ice differ clearly from each other, a good estimate of the change of the color (or, more broadly, the received signal) relative to the reference is obtained for the quantities of ice and water on the monitored surface, taking into account the changes of lightness as well as the changes of the basic road surface asphalt color at different sites. In one example of the invention, the above-mentioned reference data may be used to determine the relative ratio of the quantities of ice and water which may be used directly to determine the potential skidding at the time of observation. On the other hand, this kind of camera may also be used to determine the type of precipitation, i.e. whether the precipitation is water, snow or sleet. Also, the camera provides visual information about the general weather and for example about the degree of visibility. In one example of the invention, the camera may operate over the visible light or the infrared radiation range. On the other hand, a traditional camera that operates over the visible light range is by no means necessary for the functioning of the invention.
One or more containers 11 containing the employed anti-freeze agent may be disposed at a suitable site on the roadside. In a preferred embodiment, about 50% potassium formiate solution is used as the agent, but the use of for example an aqueous solution containing sodium chloride or calcium chloride is also possible. From the containers 11, the fluid is led forth through supply pipes 12 to the nozzles 13. The pipes 12 are dimensioned longitudinally so as to provide sufficient fluid pressure for the nozzles 13. The pipes 12 are disposed slightly below the road surface level so that there is no risk of the pipes below the roadway becoming exposed due to formation of wheel tracks.
In one example of the system of the invention, a technical room 18 constitutes an essential feature, accommodating part or all of the data processing logic required by the invention. In practice, the technical room may accommodate a server 14 which may be connected through an Ethernet connection to a radio transmitter 15. The server 14 is thus preferably connected to the outside world through the internet. In one embodiment, the radio transmitter 15 uses a 450MHz operating frequency. The technical room 18 also comprises a separate logic unit 16 that functions as the actual controller between the server 14 and the anti-freeze fluid supply apparatus 11. Required between the server 14 and the logic unit 16 is a router 17 which additionally provides a fiber connection to monitoring devices 10 that monitor the road surface. The router 17 may also have a proper radio connection. Provided from the technical room 18 is also voltage feed to separate power supply modules 19 disposed on the roadside and transferring electrical energy to the cameras 10 as well as to the warming cables which are described in more detail below. In one embodiment of the invention, one or more fluid containers 11 containing the anti-freeze agent are specifically disposed in the technical room 18, wherein the fluid containers are controlled by the logic unit 16. Also other alternative techniques, devices and routings between them can be used to provide the functionalities of the above-described technical room.
From the technical room, it is possible to establish a telecommunication connection for example to the premises of a system administering party (i.e. "the control room"), wherein the monitoring data from the site, for example in the form of camera images, temperature data and status data of the apparatus (whether the apparatus is switched on or off at the time of observation, whether any of the parts have been damaged, and other operational parameters) can be transferred to the administering party. In addition, this allows remote control of the system. It can be, for example, arranged so that the apparatus normally operates automatically by the technical room internal control process, but when a problem or a fault situation emerges, a notification is sent to the control room. From the control room, it is also possible to manually issue a control command for switching the warming on or off separately for each of the nozzles if the automatic control does not for some reason function as desired.
An exemplifying drawing of the nozzles used in the invention for spraying the fluid as seen from different directions 20 to 25 is presented in Fig. 2. The purpose of the nozzle is to spray the fluid as evenly and circularly as possible around the nozzle so that the spraying angle, as viewed upwardly from the ground plane, is relatively small, less than 45 degrees, and, most typically, an angle of less than 20 degrees is used, as can be seen from cross-section 23. In this manner, the risk of the road users being alarmed of the activated jets when the spraying system is switched on becomes smaller. This can be taken into account also by keeping the nozzle port 27 small enough and the pressure suitably adjusted so that the jet is almost invisible from far. In a preferred example of the invention, the nozzle comprises six openings 26, 27 which spray anti-freeze agent in six different directions at even spaces. In one embodiment of the invention, one nozzle consumes about 100 to 200 W of electric power. The anti-freeze agent spraying angle may also be adjusted, if necessary, as well as the diameter of the nozzle opening 27. In this connection, the fluid pressure as well as the flow rate of the nozzle can also be measured.
In using the potassium formiate solution or some other solution it should be noted that when spraying the solution for example during mild frost it melts the ice on the road surface into water. This thins down the concentration of the solution itself, which further reduces its frost resistance, i.e. raises the freezing point of the solution closer to zero degrees. Since the freezing point of a 50% potassium formiate solution is about -16°C, it is mostly usable for example in the current weather conditions of the Finnish winter.
In the field of the invention, it is important to ensure that the nozzles stay unfrozen and operational at al times. Therefore, anticipation is important, not merely the reliance on measurement results at the time of observation. On the other hand, an important aspect of energy consumption is that the nozzles should not be warmed to no effect, i.e. when there is no risk of freezing without warming in light of the current information. Thus, the warming should be controlled by intelligent logic.
In the present invention, the nozzles are warmed by a so-called self-adjusting warming cable. One option is to use a thermal resistance. The warming cable is provided so as to provide high resistance which produces plenty of energy converted into warmth from electrical energy. Further, a warming cable of good tolerance for physical stress, i.e. to be installed as surrounded by soil, asphalt or other material, is preferably selected for use in the invention. Also, the warming cable is characterized in that the resistance is reduced as the temperature rises. This property makes the warming process practical, because when the need of warming is at the highest, the warming efficiency is high as well.
Fig. 3 presents an arrangement for warming the nozzle. In this embodiment, a warming cable 30 is disposed in a circular coil in the proximity of the nozzle 31. The cable 30 may, for example, be installed in a coil in a hole provided in the ground, and the supply pipe 32 may be directed close to the coil so that the nozzle 31 can be installed concentrically over the cable coil 30. The nozzle supply pipe 32 and the cable 30 may be fixed to one another outside the cable coil, if necessary, to facilitate the installation.
The essential feature in the present invention is that the opening 26, 27 of the nozzle never freezes. Therefore, the warming method of the invention is essentially intelligent so as to be able to anticipate the future conditions. By means of the temperature sensors, the color data from the road surface, other employed sensors and the weather reports, information about the risk of freezing is provided at each time of observation. This can be defined for example as a specific temperature threshold value or as a limit value of the above-described color change, wherein the control logic switches the warming cables on when the value is exceeded. Each of the nozzles may be controlled separately and the control may be adjusted as a function of time, so that the nozzle may, for example, be warmed temporally for one specific period of time, or so that the nozzle is warmed in pulses, in which case the warming is periodically on and periodically off. In this manner, it is possible to optimize the operation of the apparatus as well as the energy consumption.
In one embodiment of the invention, a temperature sensor is installed in the immediate connection to each nozzle, in such manner that the sensor is able to measure the temperature at the opening of the nozzle without interference with the temperature measurement by the warmth provided directly from the warming cable.
In one embodiment of the invention, the data about the temperature of the air and the road surface (and further the variation trend of the above-mentioned variables, meaning in this connection the rate of temperature change), the data about the atmospheric humidity, the intensity and type of precipitation, the quantities of ice and water and their relative ratio on the road surface, the strength and direction of the wind, and visual information about the general weather and for example the visibility provided by the camera may be collected by the separate weather station which may be disposed either in the technical room or in a separate unit by the road used as the installation site. The obtained data can be combined with an estimate on the development of the weather and the temperature in the near future, provided from weather reports.
Start conditions for activating the warming may be set for the control logic of the apparatus. A start condition may for example state that temperature of the road surface sinks below +3 degrees, the temperature trend is descending, and the weather report forecasts frosty weather. The conditions for the control logic may be set before the apparatus is brought to use, or they may be changed later in situ at the technical room or remotely from the control room.
In one embodiment of the invention, the control logic may be arranged to switch the warming on or off based on at least one of the following items: temperature on the road surface at the time of observation, weather report for the next few hours, rate of the temperature change during a specific period before the time of observation, presence of a layer of snow over the nozzles, intensity of snowfall, as the quantity of ice exceeds a preset threshold value in the ice-water mixture on the road surface. In one embodiment of the invention, the warming efficiency provided by the cable may be adjusted steplessly for each nozzle.
The temperature of the nozzles should be monitored at suitable intervals after the warming has been activated. Based on this monitoring data combined with the measurement results from the weather station and the forecast provided by the weather report, the control logic determines whether the warming elements must be switched on again in a given mode. The objective is to utilize the constant monitoring of the road surface and the automatic control of the warming of the spraying apparatus to ensure functioning of the apparatus and thus the safety of the road surface from the skidding perspective as well as possible.
In the invention, the warming may be switched on manually, if necessary, either from the technical room or remotely from the premises of the system administrator. In a preferred embodiment, the system operates completely automatically after the apparatus has been installed and the required use parameters have been set for the control logic.
In one embodiment of the invention, the measurement parameters from the weather station and the spraying and warming element use data parameters from the control logic may be collected in a log file separately for each site over a desired period. The log file may be stored for example on the computer in the technical room so as to be accessible to the control logic. The log data may thus be further used for improving the operation of the control logic, i.e. the intelligence of the apparatus. The longer the period of use of the apparatus at a specific site, the more useful is the log data to optimize the spraying and the warming of the nozzles.
The nozzles of the spraying apparatus may be installed for example between the traffic lanes in the case of a two-lane road or on the shoulder edge barrier in the case of an undivided road. The nozzles are embedded in the road so that their upper surface does not deviate significantly from the road surface level. The nozzle and the supply pipeline may be installed in a hole and a track on the road surface, and, after installation of the nozzle apparatus, the void left in the hole may be filled with suitable filling material.
The method of controlling and warming the spraying nozzles according to the present invention may be carried out as a computer program stored on a computer-readable medium. The computer program may be run, in a preferred embodiment, by the processor of the computer disposed in the technical room. Another alternative is to run the computer program on an external computer used for the control.
The invention is not limited merely to the exemplifying embodiments referred to above; instead, many variations are possible within the scope of the inventive idea defined by the claims.

Claims

A method for warming a nozzle in a fluid spraying apparatus comprising at least one nozzle, a fluid container, a pipeline between the fluid container and the nozzles, and control logic for the apparatus, characterized in that the method comprises the steps of:
measuring at least one of the following parameters: quantity of ice in aqueous solution, outside-air temperature, temperature of the monitored surface, temperature of the nozzles, atmospheric humidity, strength of wind, intensity and type of precipitation, image of the monitored surface;

warming at least one of the nozzles by a warming element when a desired warming switch-on limit condition is fulfilled, wherein the switch-on limit condition is defined by at least one measured parameter; and

stopping the warming of the warmed nozzle when a desired warming switch-off limit condition is fulfilled, wherein the switch-off limit condition is defined by at least one measured parameter.
The method according to claim 1, characterized in that the monitored surface is a traffic way and the sprayed fluid is an anti-freeze agent.
The method according to claim 1, characterized in that the method further comprises the step of:
re-measuring said parameters during the warming of the nozzle before switching the warming of the nozzle off.
The method according to claim 1, characterized in that the method further comprises the steps of:
establishing an image of the monitored surface in advance when the surface is dry and unfrozen;

establishing an image of the monitored surface at the time of observation; and

based on the change in said images, determining the possible presence of water and/or ice on the surface, which information is transferred to the control logic.
The method according to claim 1, characterized in that the method further comprises the steps of:
collecting the measured parameters and the status data of the apparatus on a control logic server; and

sending an alarm to an external control room if any part of the apparatus is damaged or if the conditions on the monitored surface become dangerous.
The method according to claim 1, characterized in that said warming element is a self-adjusting warming cable installed as a coil in the immediate proximity of the nozzle.
The method according to claim 1, characterized in that said warming element is a thermal resistance installed in the immediate proximity of the nozzle.
The method according to claim 1, characterized in that the method further comprises the steps of:
monitoring the variation trend of the parameters as a function of time;

supplying a current weather report to the control logic; and

determining the need to warm the nozzles based on the parameters, the variation trend thereof and the weather report.
The method according to claim 1, characterized in that the method further comprises the step of:
providing the control of the warming to be separate for each of the nozzles and to operate as a function of time either non-recurrently or as switched on in pulses.
The method according to claim 1, characterized in that the method further comprises the steps of:
collecting the measurement parameters and the apparatus use parameters in a log file; and

using the log file data to optimize the use of the nozzles.
A system for warming a nozzle in a fluid spraying apparatus, the system comprising:
at least one nozzle (13, 20-25, 31);

a fluid container (11); and

a pipeline (12) between the fluid container and the nozzles;
characterized in that the system further comprises:
sensors (10) for measuring at least one of the following parameters: quantity of ice in aqueous solution, outside-air temperature, temperature of the monitored surface, temperature of the nozzles, atmospheric humidity, strength of wind, intensity and type of precipitation, image of the monitored surface;

a technical room (18) including a processor (14), control logic (16) for the apparatus, and a memory unit (14);

at least one warming element (30) for respectively warming at least one nozzle (13, 20-25, 31) when a desired warming switch-on limit condition is fulfilled, wherein the switch-on limit condition is defined by at least one measured parameter; and

for stopping the warming of the warmed nozzle (13, 20-25, 31) when a desired warming switch-off limit condition is fulfilled, wherein the switch-off limit condition is defined by at least one measured parameter.
The system according to claim 11, characterized in that the system further comprises:
a control room which can be contacted from the technical room (18) to transfer the measurement parameters and control commands between them.
The system according to claim 11, characterized in that the system further comprises:
a separate weather station (10) arranged to measure the above-mentioned parameters continuously or at the desired times.
The system according to claim 11, characterized in that the system further comprises:
at least one camera for taking an image of the monitored surface at the desired times, so that the received image signal is in the range of a desired frequency band.
A computer program for controlling the warming of a nozzle in a fluid spraying apparatus comprising at least one nozzle, a fluid container, a pipeline between the fluid container and the nozzles, and control logic for the apparatus, characterized in that the computer program comprises program code which, when run on a data processing device, has been arranged to execute the steps of:
controlling a measurement of at least one of the following parameters: quantity of ice in aqueous solution, outside-air temperature, temperature of the monitored surface, temperature of the nozzles, atmospheric humidity, strength of wind, intensity and type of precipitation, image of the monitored surface;

commanding a warming of at least one nozzle performed by a warming element to be activated when a desired warming switch-on limit condition is fulfilled, wherein the switch-on limit condition is defined by at least one measured parameter; and

commanding the warming of the warmed nozzle to be stopped when a desired warming switch-off limit condition is fulfilled, wherein the switch-off limit condition is defined by at least one measured parameter.