Condensing heat exchanger and water heater comprising same

Abstract

The utility model provides a condensing heat exchanger and a water heater including the same, the condensing heat exchanger comprises a housing and a water flow channel, the housing is internally provided with an air flow through cavity which continuously extends from an air inlet to an air outlet, the water flow channel is arranged in the air flow through cavity, the air flow through cavity comprises at least two air flow channels, and the flow directions of the at least two air flow channels are alternately and oppositely arranged. The water flow channel firstly makes contact with flue gas is a high-temperature area, the gas flow channel communicated with the gas outlet is a low-temperature area, and the water flow channel passes through the low-temperature area and the high-temperature area. The water heater comprises the condensation heat exchanger. The airflow channels with the alternately and oppositely arranged circulation directions can improve the complexity of the flow channels, increase the circulation length of flue gas in the airflow circulation cavity and further prolong the circulation time of the flue gas, and are matched with the water flow channels passing through the low-temperature area and the high-temperature area, so that the water flow channels make contact with high-temperature flue gas in the high-temperature area and make contact with low-temperature flue gas in the low-temperature area; the heat exchange efficiency is improved through the maximum temperature difference.

Description

Condensing heat exchangers and water heaters including them Technical Field

[0001] This utility model relates to the field of water heaters, and in particular to a condensing heat exchanger and a water heater including the same. Background Technology

[0002] With the continuous development of gas water heater technology, improving thermal efficiency and optimizing energy utilization have become the direction of product optimization. In traditional gas water heaters, the high-temperature flue gas generated by combustion is directly discharged outdoors, resulting in a large amount of waste heat not being effectively recovered and utilized, causing significant energy waste. In order to collect waste heat, water heaters generally add a secondary heat exchange device (such as a condensing heat exchanger) to recover the waste heat from the flue gas. However, the heat exchange efficiency of existing secondary heat exchange devices is low, making it difficult to effectively improve the overall thermal utilization rate of the water heater. To further increase the heat exchange efficiency, it is necessary to install another heat exchange device, which leads to increased costs and excessive weight. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to overcome the defects of low secondary heat exchange efficiency in water heaters in the prior art, which leads to a decrease in the overall thermal efficiency of the water heater and low energy utilization rate, and to provide a condensing heat exchanger and a water heater including the same.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] This utility model provides a condensing heat exchanger, which includes a shell and a water channel. The shell has an airflow cavity that extends continuously from the air inlet to the air outlet. The water channel is disposed in the airflow cavity. The airflow cavity includes at least two airflow channels with alternating opposite flow directions. The airflow channel that first contacts the flue gas is a high-temperature zone, and the airflow channel that connects to the air outlet is a low-temperature zone. The water channel passes through the low-temperature zone and the high-temperature zone.

[0006] In this scheme, the airflow channels with alternating opposite flow directions can increase the complexity of the flow channels, increase the flow length of flue gas in the airflow cavity, and thus increase the flow time of flue gas. Combined with the water flow channels that pass through the low temperature zone and the high temperature zone, the water flow channels come into contact with high temperature flue gas in the high temperature zone and low temperature flue gas in the low temperature zone, thereby improving the heat exchange efficiency by utilizing the maximum temperature difference.

[0007] Preferably, the water channel is arranged in a spiral within the airflow cavity so that the water channel alternately flows through the low-temperature zone and the high-temperature zone multiple times.

[0008] In this design, the water flow channel is arranged in a spiral pattern, allowing the water to exchange heat between high-temperature and low-temperature zones. This maintains a suitable temperature difference between the high-temperature and low-temperature zones, improving heat exchange efficiency in the high-temperature zone and increasing latent heat release in the low-temperature zone, thereby further improving the overall heat exchange efficiency of the water heater.

[0009] Preferably, the ratio of the length of the water channel located in the low-temperature zone to its length located in the high-temperature zone is 1:2 to 1:3. And / or, the water channel has an inlet end located in the low-temperature zone so that the water flows through the low-temperature zone first.

[0010] In this design, the flue gas in the high-temperature zone carries more heat than the flue gas in the low-temperature zone. Increasing the proportion of water channels in the high-temperature zone ensures that most of the heat is exchanged there. Simultaneously, since the water inlet of the water channel has the lowest temperature, placing the inlet in the low-temperature zone allows the coldest water to contact the low-temperature flue gas, maximizing the temperature difference and improving the latent heat release efficiency of the low-temperature flue gas.

[0011] Preferably, the water flow channel includes a plurality of alternately arranged heat exchange tubes, which are interconnected by elbows, and the low-temperature zone and / or the high-temperature zone includes one or more of the heat exchange tubes.

[0012] In this design, the heat exchange tubes are connected by elbows to achieve a spiral water flow channel.

[0013] Preferably, any two adjacent heat exchange tubes are equidistant; and / or, the heat exchange tubes are disposed throughout the housing.

[0014] In this design, adjacent heat exchange tubes are spaced equidistantly, meaning the distance between them using elbows is the same. Therefore, elbows of uniform specifications can be used for connection, saving costs and facilitating installation. Simultaneously, the heat exchange tubes are installed through the outer casing, allowing the elbows to protrude from the casing, ensuring that only the heat exchange tubes remain within the airflow cavity to maximize the utilization of the heat exchange space.

[0015] Preferably, the inlet of the high-temperature zone is oriented toward at least one of the heat exchange tubes; and / or, the inlet of the low-temperature zone is oriented toward at least one of the heat exchange tubes.

[0016] In this design, the aforementioned structure allows the flue gas entering the high-temperature zone to fully contact the heat exchange tubes, thereby further improving heat exchange efficiency. Simultaneously, it also allows the flue gas entering the low-temperature zone to fully contact the heat exchange tubes, further improving heat exchange efficiency.

[0017] Preferably, the condensing heat exchanger further includes a first partition and a second partition respectively connected to opposite inner wall surfaces of the outer casing. The first partition and the second partition are respectively connected to opposite inner wall surfaces of the outer casing and extend to the opposite side. The first partition is disposed below the second partition, and the water flow channel is at least partially disposed between the first partition and the second partition.

[0018] In this solution, by setting the first and second partitions, two airflow channels with alternating opposite flow directions can be formed in the airflow cavity.

[0019] Preferably, the first partition includes a collection section extending to the opposite side and a first guide section disposed at its end, the first guide section having multiple guide surfaces arranged from top to bottom to guide condensate to the collection section, the collection section having a condensate conduit disposed thereon for discharging condensate; and / or, the second partition includes a second guide section, the second guide section having multiple guide surfaces arranged from top to bottom to guide condensate to the first partition, the first partition having a condensate conduit disposed thereon for discharging condensate.

[0020] In this solution, the above structure can guide the condensate to the collection part of the first baffle through the guide surfaces on the first and second guide parts, so as to facilitate the unified discharge of the condensate.

[0021] Preferably, the total length of the projection of the first partition and the second partition in their vertical direction is greater than the length between the outer shell and the inner wall surface.

[0022] In this design, the vertical projection of the first and second partitions is greater than the distance between the outer shell and the inner wall surface, which increases the contact area between the flue gas and the first and second partitions, thereby ensuring that the flue gas can fully contact the first and second partitions to increase the condensation effect.

[0023] Preferably, the water channel includes a plurality of alternately arranged heat exchange tubes, which are interconnected by elbows. A high-temperature zone is formed between the first partition and the second partition, and a low-temperature zone is formed between the second partition and the inner wall of the outer shell. The ratio of the number of heat exchange tubes in the high-temperature zone to the number of heat exchange tubes in the low-temperature zone is 1:2 to 1:3.

[0024] In this scheme, by setting the heat exchange tubes in the high-temperature zone and the low-temperature zone in the above proportion, it can be ensured that the heat exchange space in the high-temperature zone and the low-temperature zone are also in the above proportion. The above proportion can simultaneously ensure that the heat in the high-temperature zone is fully exchanged and the latent heat in the low-temperature zone is fully released.

[0025] This utility model also provides a water heater, which includes the condenser heat exchanger as described above.

[0026] In this scheme, the airflow channels with alternating opposite flow directions can increase the complexity of the flow channels, increase the flow length of flue gas in the airflow cavity, and thus increase the flow time of flue gas. Combined with the water flow channels that pass through the low temperature zone and the high temperature zone, the water flow channels come into contact with high temperature flue gas in the high temperature zone and low temperature flue gas in the low temperature zone, thereby improving the heat exchange efficiency by utilizing the maximum temperature difference.

[0027] The positive and progressive effects of this utility model are as follows:

[0028] This utility model provides a condensing heat exchanger and a water heater including the same. By using airflow channels with alternating opposite flow directions, the complexity of the flow channels can be increased, the flow length of flue gas in the airflow cavity can be increased, and thus the flow time of flue gas can be increased. Combined with water flow channels that pass through low temperature zone and high temperature zone, the water flow channels can contact high temperature flue gas in the high temperature zone and low temperature flue gas in the low temperature zone, thereby improving heat exchange efficiency by utilizing the maximum temperature difference. Attached Figure Description

[0029] Figure 1 is a perspective view of the condenser heat exchanger according to an embodiment of the present invention.

[0030] Figure 2 is an exploded view of the condenser heat exchanger according to an embodiment of the present invention.

[0031] Figure 3 is a schematic diagram of the distribution of heat exchange tubes in an embodiment of this utility model.

[0032] Figure 4 is a schematic diagram of the flow path of high-temperature flue gas in an embodiment of this utility model.

[0033] Figure 5 is a schematic diagram of the connection of the heat exchange tube in an embodiment of the present invention.

[0034] Figure 6 is a cross-sectional view of the condenser conduit according to an embodiment of the present invention.

[0035] Figure 7 is a bottom view of the condenser conduit according to an embodiment of the present invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] Condensing heat exchanger 1000

[0038] Casing 1

[0039] Wall panel 101

[0040] Connecting hole 102

[0041] Waterway 2

[0042] Heat exchanger tube 201

[0043] elbow 202

[0044] Airflow cavity 3

[0045] High temperature zone 301

[0046] Low temperature zone 302

[0047] Air intake 4

[0048] Air outlet 5

[0049] First partition 6

[0050] Collection Department 601

[0051] First diversion section 602

[0052] Second partition 7

[0053] Second guide section 701

[0054] Condensing pipe 8 Detailed Implementation

[0055] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0056] As shown in Figures 1-7, this embodiment provides a condensing heat exchanger 1000. As shown in Figure 2, the condensing heat exchanger 1000 includes a shell 1 and a water channel 2. The shell 1 includes four side panels 101, which form an airflow cavity 3. The lower part of the airflow cavity 3 is an air inlet 4, and the upper part is an air outlet 5. The water channel 2 is disposed within the airflow cavity 3. A partition is disposed within the airflow cavity 3, and the partition is horizontally disposed within the airflow cavity 3, thereby dividing the airflow cavity 3 into two airflow channels with alternating opposite flow directions. Preferably, there can be multiple partitions, thereby dividing the airflow cavity 3 into multiple airflow channels with alternating opposite flow directions. As shown in Figures 3 and 4, in this embodiment, the partition includes a first partition 6 and a second partition 7, which divides the airflow cavity 3 into an S-shaped airflow cavity 3.

[0057] The water flow channel 2 includes multiple alternating heat exchange tubes 201, which are interconnected by elbows 202. The water flow channel 2, formed by the elbows 202, can be placed entirely into the airflow cavity 3. Preferably, a connecting hole 102 can be provided on the wall panel 101, through which the heat exchange tubes 201 are installed inside the outer shell 1, and the elbows 202 are connected to the heat exchange tubes 201 through the connecting hole 102. The heat exchange tubes 201 being installed through the outer shell 1 allows the elbows 202 to protrude from the outer shell 1, ensuring that only the heat exchange tubes 201 are retained in the airflow cavity 3 to maximize the utilization of the heat exchange space. More preferably, any two adjacent heat exchange tubes 201 are equidistant. Equivalent equidistant ...

[0058] As shown in Figures 4 and 6, the water flow channel 2 (heat exchange tube 201) first contacts the flue gas in the high-temperature zone 301, and the air flow channel connected to the outlet 5 is the low-temperature zone 302. The water flow channel 2 passes through the low-temperature zone 302 and the high-temperature zone 301. The low-temperature zone 302 includes one or more heat exchange tubes 201, and the high-temperature zone 301 includes one or more heat exchange tubes 201. Preferably, the low-temperature zone 302 and the high-temperature zone 301 each include one or more heat exchange tubes 201.

[0059] Thus, the airflow channels with alternating opposite flow directions can increase the complexity of the flow channels, increase the flow length of flue gas in the airflow cavity 3, and thus increase the flow time of the flue gas. Combined with the water flow channel 2 that passes through the low temperature zone 302 and the high temperature zone 301, the water flow channel 2 contacts the high temperature flue gas in the high temperature zone 301 and the low temperature flue gas in the low temperature zone 302, thereby improving the heat exchange efficiency by utilizing the maximum temperature difference.

[0060] In this embodiment, the ratio of the length of the water channel 2 in the low-temperature zone 302 to its length in the high-temperature zone 301 is 1:2 to 1:3, that is, the ratio of the number of heat exchange tubes 201 in the low-temperature zone 302 to the number of heat exchange tubes 201 in the high-temperature zone 301 is 1:2 to 1:3. Compared with the flue gas in the low-temperature zone 302, the flue gas in the high-temperature zone 301 carries more heat. Increasing the proportion of water channels 2 in the high-temperature zone 301 can ensure that most of the heat is exchanged in the high-temperature zone 301.

[0061] Specifically, the water channel 2 is arranged in a spiral within the airflow cavity 3 so that the water channel 2 flows alternately through the low temperature zone 302 and the high temperature zone 301 multiple times.

[0062] In this way, the water flow channel 2 is arranged in a spiral pattern, and the water flow in the water flow channel 2 exchanges heat between the high temperature zone 301 and the low temperature zone 302. This allows the water flow to maintain a suitable temperature difference in both the high temperature zone 301 and the low temperature zone 302, thereby improving the heat exchange efficiency in the high temperature zone 301 and increasing the release of latent heat in the low temperature zone 302, thus further improving the overall heat exchange efficiency of the water heater.

[0063] In this embodiment, the airflow cavity 3 is an S-shaped airflow cavity 3 separated by a first partition 6 and a second partition 7. The first partition 6 and the second partition 7 are respectively connected to opposite inner wall surfaces of the outer shell 1 and extend towards each other, with the first partition 6 positioned below the second partition 7. As shown in Figures 3 and 4, the first partition 6 is L-shaped, meaning it includes a collection section 601 extending towards the opposite side and a first guide section 602 extending upward at its end. The first guide section 602 and the second partition 7 form the inlet of the high-temperature zone 301; the second partition 7 is an inverted L-shaped, meaning it includes a second guide section 701, which is arranged from top to bottom, and the second guide section 701 and the first partition 6 form the inlet of the low-temperature zone 302.

[0064] The water flow channel 2 includes heat exchange tubes 201 numbered 1-8, connected end-to-end as shown in Figures 3 and 5. Heat exchange tubes 201 1 and 6 are located in the low-temperature zone 302, while heat exchange tubes 2, 3, 4, 5, 7, and 8 are located in the high-temperature zone 301. The number of heat exchange tubes 201 shown in the figures is for illustrative purposes only; the actual number can be adjusted according to actual needs.

[0065] As shown in Figure 3, heat exchange tubes 1-8 are arranged in a rectangular array. They are arranged in three layers in conjunction with the first partition 6 and the second partition 7, i.e., a 3+3+2 layout. In the first layer, heat exchange tubes 1, 2 and 3 are aligned. In the second layer, heat exchange tubes 4, 5 and 6 are aligned. In the third layer, heat exchange tubes 7 and 8 are staggered from the heat exchange tubes in the second layer.

[0066] Preferably, heat exchange tube 1 is the water inlet, and its placement in the low-temperature zone 302 allows water flow channel 2 to pass through it first. Since the water inlet of water flow channel 2 has the lowest temperature, placing it in the low-temperature zone 302 allows the coldest water to contact the low-temperature flue gas, utilizing the maximum temperature difference to improve the latent heat release efficiency of the flue gas. Preferably, heat exchange tube 3 faces the inlet of the high-temperature zone 301, ensuring the flue gas entering the high-temperature zone 301 fully contacts heat exchange tube 201 to further improve heat exchange efficiency. Preferably, heat exchange tube 6 faces the inlet of the low-temperature zone 302, ensuring the flue gas entering the low-temperature zone 302 fully contacts heat exchange tube 201 to further improve heat exchange efficiency. Preferably, heat exchange tube 8 is the water outlet.

[0067] As shown by the arrows in Figure 4, the flue gas flows through the airflow cavity 3. The flue gas first passes through the inlet of the high-temperature zone 301, where it undergoes significant heat exchange. Then, it passes through the inlet of the low-temperature zone 302, where it releases latent heat. The flue gas undergoes extensive heat exchange in the high-temperature zone 301, and the heat exchange tube 201 absorbs a large amount of heat from the flue gas. After passing through the high-temperature zone 301, the flue gas temperature decreases. Upon passing through the low-temperature zone 302, it exchanges heat with heat exchange tubes 1 and 6, further decreasing its temperature to release latent heat. The water in the water flow channel 2 flows from heat exchange tube 1 to heat exchange tube 8, meaning water enters at the top and exits at the bottom. The water temperature inside heat exchange tube 201 is arranged from low to high as 1-2-3-4-5-6-7-8. The flue gas temperature near the outside of heat exchange tube 201 is arranged from high to low as 3-2 / 4-5 / 8-7-6-1. With this structure, the water temperatures of heat exchange tubes 3, 2, and 4 are not high, allowing them to match the high-temperature flue gas and utilize the larger temperature difference to improve the heat absorption efficiency of heat exchange tube 201. Heat exchange tube 1 has the lowest water temperature, matching the low-temperature flue gas after heat release. This is because only heat exchange tube 1, acting as the water inlet, can maintain the maximum temperature difference with the low-temperature flue gas, thereby maximizing the release of latent heat from the low-temperature flue gas.

[0068] Specifically, one of the functions of the baffle is to collect condensate. As shown in Figure 6, the first guide section 602 has multiple guide surfaces from top to bottom to guide the condensate to the collection section 601. The collection section 601 is provided with a condensate conduit 8, which is used to drain the condensate. Alternatively, the second baffle 7 includes a second guide section 701, which has multiple guide surfaces from top to bottom to guide the condensate to the first baffle 6. The first baffle 6 is provided with a condensate conduit 8, which is used to drain the condensate. Preferably, the collection section 601 is provided with a condensate conduit 8, as shown by the arrows in Figures 6 and 7, which is used to drain the condensate. The first guide section 602 has multiple guide surfaces from top to bottom to guide the condensate to the collection section 601, while the second guide section 701 has multiple guide surfaces from top to bottom to guide the condensate to the first baffle 6.

[0069] Thus, by adopting the above structure, the condensate can be guided to the collection part 601 of the first baffle 6 by the guide surfaces on the first guide part 602 and the second guide part 701, so as to facilitate the unified discharge of condensate.

[0070] In this embodiment, as shown in FIG6, the first guide section 602 is formed by three plates connected sequentially at obtuse angles to form a guide surface facing the collection section 601. The second guide section 701 is also formed by three plates connected sequentially at obtuse angles to form a guide surface facing the collection section 601.

[0071] The total vertical projection length of the first partition 6 and the second partition 7 is greater than the length between the inner and outer walls of the outer shell 1. This greater vertical projection of the first partition 6 and the second partition 7 increases the contact area between the flue gas and the first partition 6 and the second partition 7, thereby ensuring that the flue gas can fully contact the first partition 6 and the second partition 7 to enhance the condensation effect.

[0072] Specifically, the second function of the partition is to separate the areas of the airflow cavity 3. The lateral distance between the first guide portion 602 of the first partition 6 and the second guide portion 701 of the second partition 7 is the width of the high-temperature zone 301, and the lateral distance between the second guide portion 701 and the outer shell 1 is the width of the low-temperature zone 302. This ensures that the ratio of the width of the high-temperature zone 301 to the width of the low-temperature zone 302 is 1:2 to 1:3, guaranteeing that the ratio of the number of heat exchange tubes 201 in the high-temperature zone 301 to the number of heat exchange tubes 201 in the low-temperature zone 302 is 1:2 to 1:3. This ratio simultaneously ensures sufficient heat exchange in the high-temperature zone 301 and sufficient release of latent heat in the low-temperature zone 302.

[0073] Specifically, the condenser heat exchanger 1000 of this utility model can be added to the top of the original heat exchanger to further absorb the heat of the flue gas, improve the thermal efficiency, and collect the condensate from the flue gas.

[0074] This embodiment also provides a water heater, which includes the condenser heat exchanger 1000 as described above.

[0075] Thus, by alternating opposite airflow channels, the complexity of the flow channels can be increased, the flow length of flue gas in the airflow cavity 3 can be increased, and the flow time of flue gas can be increased. Combined with the water flow channel 2 that passes through the low temperature zone 302 and the high temperature zone 301, the water flow channel 2 contacts the high temperature flue gas in the high temperature zone 301 and the low temperature flue gas in the low temperature zone 302, thereby improving the heat exchange efficiency by utilizing the maximum temperature difference.

[0076] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A condensing heat exchanger, characterized in that, The condenser heat exchanger includes a shell and a water flow channel. The shell has an airflow cavity that extends continuously from the air inlet to the air outlet. The water flow channel is located in the airflow cavity. The airflow cavity includes at least two airflow channels with alternating opposite flow directions. The airflow channel that first contacts the flue gas is a high-temperature zone, and the airflow channel that connects to the air outlet is a low-temperature zone. The water flow channel passes through the low-temperature zone and the high-temperature zone.

2. The condensing heat exchanger as described in claim 1, characterized in that, The water channel is spirally arranged within the airflow cavity so that the water flows alternately through the low-temperature zone and the high-temperature zone multiple times.

3. The condensing heat exchanger as described in claim 1, characterized in that, The ratio of the length of the water channel located in the low-temperature zone to its length located in the high-temperature zone is 1:2 to 1:3; and / or, the water channel has an inlet end, which is located in the low-temperature zone so that the water channel flows through the low-temperature zone first.

4. The condensing heat exchanger as described in claim 1, characterized in that, The water flow channel includes multiple alternating heat exchange tubes, which are interconnected by elbows. The low-temperature zone and / or the high-temperature zone includes one or more of the heat exchange tubes.

5. The condensing heat exchanger as described in claim 4, characterized in that, Any two adjacent heat exchange tubes are equidistant; and / or, the heat exchange tubes are disposed throughout the outer casing.

6. The condensing heat exchanger as described in claim 4, characterized in that, The inlet of the high-temperature zone faces at least one of the heat exchange tubes; and / or, the inlet of the low-temperature zone faces at least one of the heat exchange tubes.

7. The condensing heat exchanger as described in claim 1, characterized in that, The condensing heat exchanger further includes a first partition and a second partition respectively connected to the opposite inner wall surfaces of the outer shell. The first partition and the second partition are respectively connected to the opposite inner wall surfaces of the outer shell and extend to the opposite side. The first partition is disposed below the second partition, and the water flow channel is at least partially disposed between the first partition and the second partition.

8. The condensing heat exchanger as described in claim 7, characterized in that, The first partition includes a collection section extending to the opposite side and a first guide section disposed at its end. The first guide section is provided with multiple guide surfaces from top to bottom to guide condensate to the collection section. A condensate conduit is disposed on the collection section for discharging condensate. And / or, the second partition includes a second guide section. The second guide section is provided with multiple guide surfaces from top to bottom to guide condensate to the first partition. A condensate conduit is disposed on the first partition for discharging condensate.

9. The condensing heat exchanger as described in claim 8, characterized in that, The total length of the projection of the first partition and the second partition in their vertical direction is greater than the length between the outer shell and the inner wall surface.

10. The condensing heat exchanger as described in claim 7, characterized in that, The water channel includes multiple alternating heat exchange tubes, which are interconnected by elbows. A high-temperature zone is formed between the first partition and the second partition, and a low-temperature zone is formed between the second partition and the inner wall of the outer shell. The ratio of the number of heat exchange tubes in the high-temperature zone to the number of heat exchange tubes in the low-temperature zone is 1:2 to 1:

3.

11. A water heater, characterized in that, It includes the condensing heat exchanger as described in any one of claims 1-10.

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