EP3889358A1

EP3889358A1 - Snow melting equipment

Info

Publication number: EP3889358A1
Application number: EP21166492.5A
Authority: EP
Inventors: Pekka PUROLA
Original assignee: Lumipower Oy
Current assignee: Lumipower Oy
Priority date: 2020-04-03
Filing date: 2021-04-01
Publication date: 2021-10-06
Anticipated expiration: 2041-04-01
Also published as: EP3889358C0; FI20205349A1; FI129100B; EP3889358B1

Abstract

Snow melting equipment comprises a melting tank (10) for snow to be melted, the melting tank having a bottom (12) and walls, first melting means for melting the snow in the melting tank into meltwater, second melting means for heating the meltwater and directing the heated meltwater to the snow to be melted in the melting tank and at least one stirring means for inducing motion in the meltwater inside the melting tank. The walls of the melting tank comprise a front wall (14) and a rear wall (16), which are at opposite ends of the melting tank, and two opposite side walls, and said at least one stirring means are arranged in the front wall, rear wall and/or side walls at a distance from the bottom and the opposite wall. The flow of meltwater caused by the stirring means causes the chunks of snow floating in the meltwater to move within the melting tank, whereby the heated meltwater melts them more efficiently.

Description

Field of the invention

The invention relates to snow melting equipment comprising a melting tank for snow to be melted, the melting tank having a bottom and walls, first melting means for melting the snow in the melting tank into meltwater, second melting means for heating the meltwater and directing the heated meltwater to the snow to be melted in the melting tank and at least one stirring means for inducing motion in the meltwater inside the melting tank.

Prior art

In winter, snowfall makes it difficult for people to move about in streets, roads and yards. Therefore, snow is plowed in these areas and stored on the sides of the streets, roads and yards. In densely built-up areas, such as cities and residential suburbs, there is often no storage space for snow, which means that the snow has to be transported by trucks to designated snow dump sites. The transport distance from the snow collection site to the snow dump site is typically several kilometers. Transporting snow incurs transport costs and emissions that are harmful to the climate. In addition, snow trucks slow down other traffic. Snow collected from traffic areas contains pollutants that flow as such with the meltwater into waterbodies.
One way to reduce snow transport costs is to melt the snow into water, which is then discharged into a storm sewer after cleaning. FI123033 B and FI20145732 disclose devices for melting snow. The devices comprise a thermally insulated tank into which the snow to be melted is transferred. Inside the tank, there are pipes with water flowing in them; the water is heated by a heat exchanger connected to the district heating network, whereby the snow in the tank melts into water. Similar devices are disclosed in CA 2684863 and US 2008/0178866 . The device disclosed in US 2008/0178866 has tubes on the inner surfaces of the walls of the tank by means of which warm water is sprayed on the unmelted snow to accelerate the melting process. The problem with the above-mentioned equipment is that the snow in the tank easily remains in large chunks that float on the water and melt slowly.
WO 2012/011476 A1 discloses a snow melting device with a snow melting tank. Inside the melting tank, there are several rotating shafts with blades to enhance the melting of snow in the tank. Water or steam can be supplied into the tank via pipes. In this solution, the shafts extend from one end of the melting tank to the other, requiring a lot of space.
US 2005/0121547 discloses a snow and ice melting device in which there is at the bottom of the melting tank a rotating rotor-stator device for crushing snow chunks in the melting tank. The rotor-stator device cannot crush snow chunks floating on the surface of the water in the melting tank beyond the reach of the rotor-stator.
US 8640687 discloses a snow melting system comprising a melting tank and a hopper for receiving snow. At the bottom of the hopper there is a hole through which the snow transferred to the hopper flows into a cylindrical induction chamber below the hopper. The induction chamber is in a vertical position at the bottom of the melting tank. Inside the induction chamber is a fan pump that forces water and snow flowing out of the hopper to flow down towards the bottom of the induction chamber. In this solution, rocks or other hard objects that may be present in the snow can damage the fan pump.
An object of the invention is to provide snow melting equipment with which the drawbacks associated with the prior art can be eliminated.
The objects of the invention are achieved by snow melting equipment which is characterized by what is set out in the independent claim. Some preferred embodiments of the invention are set out in the dependent claims.

Summary of the invention

Snow melting equipment according to the invention comprises a melting tank for snow to be melted, the melting tank having a bottom and walls, first melting means for melting the snow in the melting tank into meltwater, second melting means for heating the meltwater and directing the heated meltwater to the snow to be melted in the melting tank and at least one stirring means for inducing motion in the meltwater inside the melting tank. The walls of the melting tank comprise a front wall and a rear wall, the front wall and the rear wall being at opposite ends of the melting tank, and two opposite side walls, and said at least one stirring means are arranged in the front wall, the rear wall and/or the side walls at a distance from the bottom and the opposite wall. The flow of meltwater caused by the stirring means causes the chunks of snow floating in the meltwater to move within the melting tank, whereby the heated meltwater melts them more efficiently.
The stirring means of the snow melting equipment according to the invention comprise a feed pipe, a rotatable shaft having an outer surface and a propeller arranged on the shaft for causing meltwater to flow through the feed pipe. Preferably, the propeller and at least a portion of the shaft are within the feed pipe.
In another preferred embodiment of the snow melting equipment according to the invention, the feed pipe has a first end at which the feed pipe is fixed to one wall of the melting tank, preferably the front wall, and an open second end pointing towards a second wall, preferably the rear wall. Preferably, the feed pipe has a wall with an inlet for the flow of meltwater, which inlet is in the vicinity of the first end of the feed pipe. Meltwater flows through the inlet into the feed pipes and exits at the second end of the feed pipe towards the wall of the melting tank. The flow of meltwater through the feed pipe is achieved by the rotational movement of the propeller.
In another preferred embodiment of the snow melting equipment according to the invention, there is a flow channel inside the shaft for conducting heated meltwater into the melting tank, the flow channel having at least one flow hole opening into the outer surface of the shaft. Alternatively or in addition, there may be an air duct inside the shaft for conducting compressed air to the melting tank, the air duct having at least one air hole opening into the outer surface of the shaft. Preferably, the shaft has a first end pointing towards the wall of the melting tank, preferably the rear wall, and at least one flow hole and/or air hole is at the first end of the shaft.
Yet another preferred embodiment of the snow melting equipment according to the invention comprises a conveyor having an inner portion with a first end located inside the melting tank and an outer portion with a second end located outside the melting tank. The rear wall of the melting tank has an outlet for the conveyor to pass through. Preferably, the inner portion of the conveyor is close to the bottom of the melting tank and the first end of the conveyor extends close to the front wall. Impurities heavier than water in the snow to be melted, such as sand and gravel, precipitate onto the bottom of the melting tank, with the running conveyor moving them along the bottom out of the melting tank. The motion of the meltwater inside the melting tank caused by the conveyor helps chunks of snow to mix with the meltwater.
In yet another preferred embodiment of the snow melting equipment according to the invention, said first melting means comprises an initial melting pipe at the bottom of the melting tank and said second melting means comprises post-melting pipes arranged in the walls of the melting tank with nozzles for spraying heated meltwater. The nozzles are oriented to spray heated meltwater into the central area of the melting tank. Preferably, the post-melting pipes are arranged in the side walls of the melting tank.
Yet another preferred embodiment of the snow melting equipment according to the invention further comprises a heating device for heating the meltwater. Preferably, said heating device is a heat exchanger connectable to a district heating network. The heat exchanger can be connected to the return pipe of the district heating network, so that the heating of the meltwater can be done with low-cost energy.
Yet another preferred embodiment of the snow melting equipment according to the invention further comprises circulation pipes, the circulation pipes having a first end opening into the melting tank and a second end leading to the heating device. Meltwater is passed along the circulation pipes to the heating device where it is heated to an elevated temperature. The heated meltwater is led back to the melting tank via the post-melting pipes and flow channel.
The invention has the advantage that it can melt a large amount of snow in a short time.
In addition, the invention has the advantage that the equipment is durable and reliable, because the most sensitive parts of the equipment are not located in the path of the snow to be tipped into the melting tank of the equipment.
A particular advantage of one embodiment of the invention is that it provides a cost-effective alternative to melting snow in the area of a district heating network. The processing of snow and drainage of meltwater can be done using existing infrastructure and municipal engineering facilities.

Brief description of the drawings

The invention is described in detail below. In the description, reference is made to the accompanying drawings in which

Fig. 1: shows by way of example snow melting equipment according to the invention as seen diagonally from above,
Fig. 2a: shows by way of example a longitudinal section of the equipment shown in Fig. 1,
Fig. 2b: shows a cross-section of the equipment shown in Fig. 1,
Fig. 2c: shows by way of example a longitudinal section of the stirring means belonging to the equipment shown in Fig. 2a, and
Fig. 3: shows the equipment according to the invention in a simplified schematic view.

Detailed description of the invention

Fig. 1 shows, by way of example, equipment according to the invention as seen diagonally from above. The equipment comprises a box-like melting tank 10 made of steel, preferably stainless steel, with a watertight enclosure. The enclosure comprises a bottom 12, a front wall 14 and a rear wall 16, and first and second side walls 13, 15. The free edges of the front and rear walls and the side walls define an opening through which snow can be transferred into the melting tank. The melting tank further includes an openable lid 22 attached to one side wall at one edge. The lid can be turned to a closed position, in which it substantially completely covers the opening delimited by the free edges of the front and rear walls and side walls, and to an open position, in which it does not cover the above-mentioned opening. The bottom, front and rear walls, side walls and/or lid may have a thermal insulation layer made of, for example, polystyrene or polyurethane. The size of the melting tank can be chosen according to the amount of snow to be processed. The size of the melting tank of the mobile equipment shown in Fig. 1 may be, for example, 25 m³.
At a first end of the melting tank, on one side of the front wall 14, there is a technical space 38. The technical space is a closed space with double doors 40 opening to the end of the system. Inside the technical space there is a heat exchanger 35, a circulating water pump 31 and a pump 33 for circulating meltwater. The capacity of the heat exchanger can be selected on the basis of the melting capacity required of the equipment. Theoretically, a melting power of about 90 kW is required to melt 1000 kg of snow per hour. Thus, equipment comprising a 25 m³ melting tank can have a heat exchanger with a capacity of, for example, 500 kW. The heat exchanger 35 has an inlet connection 42 and a return connection 44 for connection to the district heating network piping so that hot water flows from the district heating network through the inlet connection into the heat exchanger and cooled water flows through the return connection back to the district heating network. The technical space further contains adjustment and control means 46 for controlling the operation of the circulating water pump 31, the pump 33 and the heat exchanger 35.
The snow melting equipment further includes a conveyor 28, a first portion of which is inside the melting tank 10 and a second portion is outside the melting tank. The rear wall 16 of the melting tank has an outlet 30 through which the conveyor passes. The snow melting equipment is built in the form of a movable container.
Fig. 2a shows, by way of example, a longitudinal section of the equipment shown in Fig. 1, and Fig. 2b shows a cross-sectional view thereof at section plane A-A. In the following, both images are described simultaneously.
At the bottom of the melting tank 10, there is an initial melting pipe 34 made of stainless steel, the ends of which pass through the first and second side walls to the sides of the melting tank and further into the technical space 38. Inside the melting tank, the initial melting pipe runs along a winding route within an area bounded by the front wall, the rear wall and the side walls close to the bottom 12 of the melting tank. In the technical space, the ends of the initial melting pipe are connected to the heat exchanger 35 so that the initial melting pipe forms a closed initial melting circuit passing through the heat exchanger 35, with water therein being circulated by means of the circulating water pump 31 (Fig. 1). The initial melting pipe constitutes a first melting means by which snow transferred to the melting tank is melted into meltwater. Inside the initial melting pipe, there may be an electric heating cable (not shown) to prevent water from freezing inside the initial melting pipe during operational outages.
Inside the melting tank, there are also second melting means which raise the temperature of the meltwater and direct the heated meltwater to the as yet unmelted snow in the melting tank. The second melting means comprise circulation pipes 37, with first ends thereof opening into the melting tank and second ends being connected via a collector pipe (not shown) to the heat exchanger 35. The collector pipe passes through the heat exchanger, whereby the temperature of the meltwater flowing in it rises. The heated meltwater exits the heat exchanger to a distribution pipe (not shown) from which a plurality of post-melting pipes 32 branch. The post-melting pipes are straight pipes located inside the melting tank on the first and second side walls. The section between the circulation pipes and the post-melting pipes has a pump 33 (Fig. 1) for pumping meltwater from the lower part of the melting tank via the circulation pipes and the collector pipe to the heat exchanger and from the heat exchanger via the distribution pipe and post-melting pipes back to the melting tank. The pumping capacity of the pump can be in the order of 22 m³/h. The snow melting equipment depicted has two circulation pipes 37 on each long side of the melting tank and two circulation pipes at the front end of the melting tank. The ends of the circulation pipes on the sides of the melting tank open into the side walls 13, 15 of the melting tank and of the circulation pipes at the front end of the melting tank open into the front wall 14 near the bottom 12 of the melting tank.
Mounted on the side walls of the melting tank, the post-melting pipes have spaced-apart nozzles 36 which emit a jet of heated meltwater towards the central part of the melting tank. When operated, the snow melting equipment has meltable snow inside the melting tank, so that the heated jet of meltwater emitted through the nozzles is directed towards the snow to be melted.
The front wall 14 of the melting tank has stirring means for causing the meltwater inside the melting tank and the chunks of snow and ice floating therein to move inside the melting tank 10. The stirring means comprises a feed pipe 18, the imaginary central axis of which is substantially parallel to the direction of the bottom, i.e., it is substantially horizontal when the melting equipment is in its operating position on a substantially horizontal base. The structure of the stirring means is described in more detail in connection with the description of Fig. 2c.
The snow melting equipment further includes a conveyor 28, an inner portion of which is inside the melting tank 10 and an outer portion of which is outside the melting tank. The first end of the inner portion of the conveyor extends almost to the front wall 14. The obliquely rising outer portion of the conveyor begins at one end of the inner portion parallel to the bottom and rises through the outlet 30 in the second end wall 16 to the outside of the melting tank. The other end of the conveyor is outside the melting tank at the height of the upper edge of the melting tank enclosure. On the outer surface of the other end wall 16, there is a waterproof protective trough 52 surrounding the outer portion of the conveyor.
The conveyor 28 is a conveyor known from prior art with two endless chains 60 revolving around end rollers 58. The side walls 13, 15 of the melting tank have an upper part and a lower part which are substantially parallel and substantially perpendicular to the bottom 12. The distance between the lower parts of the side walls is equal to the distance between the opposite side walls of the protective trough and less than the distance between the upper parts of the side walls. The first chain is arranged inside the melting tank next to the lower part of the first side wall 13 and the second chain is arranged next to the lower part of the second side wall 15. The lower parts of the side walls and the side walls of the protective trough have rails (not shown) along which the chains run. The chains are connected to each other by beams 56 transverse to the longitudinal direction of the conveyor. The beams are about 50 cm apart. In connection with the end roller at the second end of the conveyor, there is a motor for rotating the end roller. As the end roller rotates, the chains revolve around the end rollers so that the upper portion of the chain moves toward the front wall 14 and the lower portion of the chain moves away from the front wall. The conveyor is mounted on the side walls so that as the chains rotate, the beams attached to the chains, while moving away from the front wall, run very close to the bottom of the melting tank, pushing material heavier than water, which has accumulated on the bottom, along the bottom and the inclined wall surface towards the second end of the conveyor. The initial melting pipe 34 is within the melting tank 10 near the bottom 12 so that the conveyor beams 56 move above the initial melting pipe as they move toward the front wall, and below the initial melting pipe as they move away from the front wall.
Between the upper and lower parts of the side walls is a middle part which is in an oblique position relative to the upper and lower parts. The sloping middle parts of the side walls of the melting tank guide impurities in the meltable snow, such as sand and gravel, which are heavier than water, to the bottom of the melting tank, from where they are conveyed outside the melting tank by the conveyor when it runs. The width of the conveyor is chosen such that the beams extend from the lower part of the first side wall to the lower part of the second side wall.
Each side wall 13, 15 of the melting tank has an overflow pipe 48 in a position substantially perpendicular to the bottom 12, the upper end of which opens into the melting tank. The oblique middle parts of the side walls have recesses 64 in which the overflow pipes are placed. The overflow pipes are connected at their lower end to a discharge pipe 62 outside the melting tank (Fig. 2b). The first end of the overflow pipe is located at a distance from the bottom 12 of the melting tank, leaving a watertight water space for the meltwater in the lower part of the melting tank. The distance of the first end of the overflow pipe can be chosen depending on the desired water volume for the melting tank. The distance of the first end of the overflow pipe from the bottom can be, for example, 100 cm, whereby the water volume is 9-10. When the surface of the meltwater rises to the level of the first end of the overflow pipe, the meltwater can flow along the overflow pipe out of the melting tank into the discharge pipe. The end of the discharge pipe is intended to be connected to a storm sewer. Around the first end of the overflow pipe is a protective frame 50 open at the bottom, which prevents snow and ice floating on the surface of the meltwater from entering the overflow pipe.
Fig. 2c shows, by way of example, a longitudinal section of the stirring means belonging to the snow melting equipment according to the invention. The melting means includes a feed pipe 18 attached at its first end to the front wall 14 of the melting tank so that the imaginary central axis of the feed pipe is substantially perpendicular to the plane of the front wall. The feed pipe is shown in the figure in a longitudinally split cross-sectional view. The second end of the feed pipe is open and points towards the rear wall of the melting tank. The distance of the central axis of the feed pipe from the bottom of the mixing tank can be 500-600 mm. The diameter of the feed pipe can be 15-50 cm, preferably 20-30 cm. The length of the feed pipe can be 25-60 cm, preferably 30-50 cm. The wall of the first end of the feed pipe has an inlet 19 through which meltwater can flow into the feed pipe.
Inside the feed pipe there is a shaft 20, the longitudinal direction of which is substantially the same as the direction of the central axis of the feed pipe 18. The shaft has a first end facing the rear wall of the melting tank and a second end passing through a hole in the front wall and extending into the technical space 38. At the second end, there is a motor (not shown) which causes the shaft to rotate. On the outer surface of the shaft, there is a propeller 21 with four blades. The propeller is attached to the shaft in the section between the first end of the shaft and the inlet 19 of the feed pipe. The propeller blades are oriented so that rotation of the shaft causes the propeller attached to it to produce a flow inside the feed pipe that forces the meltwater in the feed pipe through the open second end of the feed pipe and out of the feed pipe. Meltwater exiting the feed pipe is replaced by meltwater flowing into the feed pipe through the inlet. The rotating propeller thus generates a flow of meltwater inside the melting tank from the feed pipe towards the rear wall of the melting tank, which mixes meltwater with the chunks of snow floating in the meltwater.
Inside the shaft is a flow channel 24, the first end of which opens through flow holes 25 at the first end of the shaft into the outer surface of the shaft. The second end of the flow channel opens through the second end of the shaft into the technical space, where it connects to a pipe (not shown) coming from the heat exchanger and supplying heated meltwater. When the equipment is operated, the heated meltwater is pumped from the heat exchanger to the flow channel, from where it discharges through the flow holes into the feed pipe and mixes with the meltwater flow generated by the rotating propeller, raising the temperature of the flow. The elevated temperature of the meltwater flow accelerates the melting of the chunks of snow.
Inside the shaft, there is also an air duct 26, the first end of which opens through air holes 27 at the first end of the shaft into the outer surface of the shaft. The second end of the air duct opens through the second end of the shaft into the technical space, where it connects to a compressed air pipe (not shown) coming from a compressor (not shown). When the equipment is operated, compressed air can be directed to the air duct, from where it discharges through the air holes into the feed pipe and mixes with the meltwater flow generated by the rotating propeller. Compressed air causes the meltwater flow to effervesce, which is believed to contribute to the disintegration of the chunks of snow that hit the flow. The air duct is not a necessary part of the stirring means, and the stirring equipment can also be implemented without it.
Fig. 3 shows an equipment according to the invention in a simplified diagram. The equipment is designed to be connected to a district heating network so that the water of the district heating network is led to flow through the inlet connection 42 into the heat exchanger 35, with cooled water flowing out of the heat exchanger via the return connection 46. The water of the district heating network cools by approximately 20°C as it flows through the equipment. The initial melting pipe 34 forms a closed initial melting circuit which passes through the heat exchanger 35 and in which water is circulated by means of a circulating water pump 31. The water flowing in the initial melting circuit is heated in the heat exchanger to a suitable initial melting temperature.
Meltwater melted by the initial melting pipe is pumped by the pump 33 along the circulation pipes 37 and the collector pipe to the heat exchanger, where its temperature rises. The heated meltwater is led through a distribution pipe into the post-melting pipes 32 and the flow channel 24, along which the meltwater is led back to the melting tank 10. In the heat exchanger, the meltwater heats up to 20-30°C. The heated meltwater is sprayed from the post-melting pipes through nozzles on the snow in the melting tank. Some of the heated meltwater is led through the flow channel in the shaft into the feed pipe, where it mixes with the meltwater flowing in the feed pipe. As the surface of the meltwater rises to the height of the first end of the overflow pipe, meltwater begins to drain from the melting tank through the overflow pipe 48 into a discharge pipe and further into the storm sewer.
The equipment according to the invention is transported to a suitable location in the area of a property along a district heating network. The location can be, for example, the yard area of an apartment block, industrial plant or commercial building. The equipment is then connected to the district heating network by coupling the inlet connection 42 and the return connection 46 of the equipment to the district heating network piping. Preferably, the inlet connection and the return connection are coupled to the return pipe of the district heating network. The overflow pipe 48 of the equipment is connected to the storm sewer by means of a connecting pipe and the equipment is connected to the power grid. The equipment is then ready for use. The equipment is used during the winter, when snow falls on areas that need to be kept trafficable. For the summer, when there is no snow, the equipment can be moved away from the area of the property.
Snow that has fallen is collected with snow removal equipment from the area to be cleaned and transferred to the melting tank 10 of the equipment. The equipment is used continuously as long as there is snow to melt. In continuous operation, new snow is continuously introduced into the melting tank so that the interior of the melting tank is substantially filled with snow and meltwater. The meltwater generated when the snow melts is continuously discharged through the overflow pipe into the storm sewer. When there is no more snow to melt, the equipment can be stopped and the meltwater left in the melting tank can be discharged to the storm sewer via a drain valve.
The equipment shown in the figures is arranged in the form of a container movable by a truck. The equipment can also be constructed in the form of fixed embodiments. A fixed installation may include a melting tank that can be at least partially embedded in the soil. An embedded melting tank may have a mouth which extends to the surface of the ground and is closed with an openable lid.
The hot water fed to the heat exchanger can be produced by any method or fuel but the most economically advantageous result is often achieved when the thermal energy used to melt the snow is produced in a district heating plant. A particularly advantageous result is achieved when the district heating plant producing the thermal energy is a back-pressure plant suitable for cogeneration of electricity and heat, and the thermal energy for the equipment is obtained from the return water flowing in the district heating network. Instead of and in addition to the heat exchanger, the snow melting equipment can be equipped with a burner burning solid, liquid or gaseous fuel, which produces the thermal energy needed to melt the snow. Such snow melting equipment can also be used outside the district heating network.
Some preferred embodiments of the snow melting equipment according to the invention have been described above. The invention is not limited to the solutions described above, but the inventive idea can be applied in various ways within the scope set by the claims.

List of reference numbers:

10	melting tank	40	double doors
12	bottom	42	inlet connection
13	first side wall	46	return connection
14	front wall	48	overflow pipe
15	second side wall	50	protective frame
16	rear wall	52	protective trough
18	feed pipe	56	beam
19	inlet	58	end roller
20	shaft	60	chain
21	propeller	62	discharge pipe
22	lid	64	recess
24	flow channel
25	flow hole
26	air duct
27	air hole
28	conveyor
30	outlet
31	circulating water pump
32	post-melting pipe
33	pump
34	initial melting pipe
35	heat exchanger
36	nozzle
37	circulation pipe
38	technical space

Claims

Snow melting equipment comprising a melting tank (10) for snow to be melted, the melting tank having a bottom (12) and walls, first melting means for melting the snow in the melting tank into meltwater, second melting means for heating the meltwater and directing the heated meltwater to the snow to be melted in the melting tank and at least one stirring means for inducing motion in the meltwater inside the melting tank (10), characterized in that the walls of the melting tank (10) have a front wall (14) and a rear wall (16), the front wall (14) and the rear wall (16) being at opposite ends of the melting tank (10), and two opposite side walls (13, 15), and said at least one stirring means is arranged in the front wall (14), rear wall (16) and/or side walls (13, 15) at a distance from the bottom (12) and the wall opposite to the wall in which the stirring means are arranged, and said stirring means comprises a feed pipe (18), a rotatable shaft (20) having an outer surface, and a propeller (21) arranged on the shaft (20) for causing meltwater to flow through the feed pipe (18).
The snow melting equipment of claim 1, characterized in that the propeller (21) and at least a portion of the shaft (20) are inside the feed pipe (18).
The snow melting equipment of claim 1 or 2, characterized in that the feed pipe (18) has a first end at which the feed pipe (18) is fixed to one wall of the melting tank (10), preferably the front wall (14), and an open second end pointing towards a second wall of the melting tank (10), preferably the rear wall (16).
The snow melting equipment of claim 3, characterized in that the feed pipe (18) has a wall with an inlet (19) to let meltwater to flow through, which inlet (19) is in the vicinity of the first end of the feed pipe (18).
The snow melting equipment of any of claims 1-4, characterized in that inside the shaft (20), there is a flow channel (24) for conducting heated meltwater into the melting tank (10), the flow channel (24) having at least one flow hole (25) opening into the outer surface of the shaft (20).
The snow melting equipment of any of claims 1-5, characterized in that inside the shaft (20), there is an air duct (26) for conducting compressed air into the melting tank (10), the air duct (26) having at least one air hole (27) opening into the outer surface of the shaft (20).
The snow melting equipment of claim 6, characterized in that the shaft (20) has a first end pointing towards a wall of the melting tank (10), preferably the rear wall (16), and at least one flow hole (25) and/or air hole (27) is at the first end of the shaft (20).
The snow melting equipment of any of claims 1-7, characterized in that the equipment comprises a conveyor (28) having, inside the melting tank (10), an inner portion with a first end and, outside the melting tank (10), an outer portion with a second end, and the rear wall (16) has an outlet (30) to let the conveyor pass through.
The snow melting equipment of claim 8, characterized in that the inner portion of the conveyor (28) is close to the bottom (12) of the melting tank (10) and the first end of the conveyor (28) extends close to the front wall (14).
The snow melting equipment of any of claims 1-9, characterized in that said first melting means comprises an initial melting pipe (34) at the bottom (12) of the melting tank (10), and said second melting means comprises post-melting pipes (32) arranged in the walls of the melting tank (10) with nozzles (36) for spraying heated meltwater.
The snow melting equipment of claim 10, characterized in that the post-melting pipes (32) are arranged in the side walls (13, 15) of the melting tank (10).
The snow melting equipment of any of claims 1-11, characterized in that the equipment further comprises a heating device for heating the meltwater.
The snow melting equipment of claim 12, characterized in that said heating device is a heat exchanger (35) connectable to a district heating network.
The snow melting equipment of any of claims 12 or 13, characterized in that the equipment further comprises circulation pipes (37), the circulation pipes (37) having a first end opening into the melting tank (10) and a second end leading to the heating device.