External pressure type ultrafiltration membrane assembly and ultrafiltration equipment

Abstract

The utility model discloses an external pressure type ultrafiltration membrane component and ultrafiltration equipment, and relates to the technical field of ultrafiltration equipment, in particular to the external pressure type ultrafiltration membrane component and the ultrafiltration equipment, the external pressure type ultrafiltration membrane component comprises a shell which is cylindrical, the interior of the shell is sequentially divided into a water inlet cavity, a filtering cavity and a water outlet cavity through two groups of end sealing glue, the water inlet cavity is communicated with a water inlet, and the water outlet cavity is communicated with a water outlet; the supporting rod is arranged in the filtering cavity, the supporting rod is overlapped with the center line of the shell, and the two ends of the supporting rod are fixedly connected with the end sealing glue; according to the external pressure type ultrafiltration membrane assembly and the ultrafiltration equipment, the supporting rod is additionally arranged in the center of the shell to improve the stability of the membrane assembly, and the inner wall of the shell is partitioned in a fan-shaped manner through the partition plates, so that water is distributed in the shell in a dispersed manner, water distribution dead angles are reduced, meanwhile, the pressure borne by different positions of the membrane assembly is balanced, and contamination of the membrane assembly is relieved; and meanwhile, uniform distribution of a gas phase in the gas scrubbing process is facilitated, and the cleaning effect of gas scrubbing on the membrane module is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of ultrafiltration equipment, and more specifically, to an external pressure type ultrafiltration membrane module. In addition, the utility model also relates to an ultrafiltration equipment including the above external pressure type ultrafiltration membrane module. Background Art

[0002] Ultrafiltration is a pressure-driven membrane separation technology. Under a certain pressure drive, the solvent and solutes smaller than the pore size pass through the ultrafiltration membrane, while solutes larger than the pore size are retained on the other side of the membrane, so as to achieve the functions of solution separation, purification and concentration.

[0003] Ultrafiltration can effectively remove particles, colloids, microorganisms, heat sources and macromolecular organic matters in water body, and its equipment is simple and the cost is low. It has been widely used in the fields of biology, medicine, food, chemical industry, water treatment, etc., and is an important membrane separation technology. Due to the application of ultrafiltration technology in the field of water treatment, ultrafiltration membranes and modules have received more and more attention. As a mature process, the external pressure type ultrafiltration membrane has been widely used. Among them, the hollow fiber external pressure type ultrafiltration membrane module is the most widely used form of external pressure type ultrafiltration membrane module in industrial applications due to its advantages such as high packing density and large water production.

[0004] The hollow fiber external pressure type ultrafiltration membrane module generally consists of a pressure-bearing shell and hollow fiber ultrafiltration membrane filaments inside the shell; the pressure-bearing shell is composed of a cylindrical shell and end caps installed at the upper and lower ends of the cylindrical shell, and water inlets and outlets are respectively arranged on the upper and lower end caps; the hollow fiber membrane filaments are axially placed in the circular cylinder, and both ends are bonded to both ends of the cylinder through epoxy resin.

[0005] Most of the membrane filaments of ultrafiltration membrane columnar membrane products are more than 1.5m in length. If the center pipe is used for water distribution, the tube length of the center pipe is relatively long, and the resistance of water distribution will change along the axis, resulting in uneven pressure inside the membrane module, that is, the pressure-bearing of the membrane module far from the water inlet end is less than that of the other end, resulting in uneven membrane module pollution and accelerating the membrane pollution process;

[0006] During the air scrubbing process, the scrubbing of pollutants adhering to the membrane surface is mainly through the shear stress generated by the bubbles in the gas-liquid two-phase flow passing through the membrane surface. For existing columnar membrane products, there is a problem of uneven gas phase distribution during air scrubbing, and there are scrubbing dead corners, resulting in poor cleaning effect of the membrane module.

[0007] In summary, how to provide an external pressure type ultrafiltration membrane module that can avoid uneven pressure-bearing and pollution imbalance of the membrane module and can avoid the occurrence of air scrubbing dead corners is an urgent problem to be solved by those skilled in the art at present. Summary of the Utility Model

[0008] In view of this, the purpose of the present utility model is to provide an external pressure ultrafiltration membrane module. By adding a support rod in the center of the housing, the stability of the membrane module is increased. And through the spacer plate to fan-shaped partition the inner wall of the housing, so that the water distribution in the housing is in a dispersed type, reducing the dead angle of water distribution. At the same time, the pressure bearing at different positions of the membrane module is balanced, slowing down the fouling of the membrane module. At the same time, it is beneficial to the uniform distribution of the gas phase during the air scrubbing process, ensuring the cleaning effect of the air scrubbing on the membrane module.

[0009] Another purpose of the present utility model is to provide an ultrafiltration device including the above-mentioned external pressure ultrafiltration membrane module, which has the same technical features and can solve the same technical problems.

[0010] In order to achieve the above purpose, the present utility model provides the following technical solutions:

[0011] An external pressure ultrafiltration membrane module, comprising:

[0012] A housing, which is cylindrical, and is sequentially divided into a water inlet chamber, a filtration chamber and a water outlet chamber by two groups of end sealants inside. The water inlet chamber is communicated with a water inlet, and the water outlet chamber is communicated with a water outlet;

[0013] A support rod, arranged in the filtration chamber, the support rod overlaps with the center line of the housing, and both ends of the support rod are fixedly connected to the end sealant;

[0014] Spacer plates, at least two groups, and arranged in the filtration chamber, dividing the filtration chamber into several groups of fan-shaped partitions. There is a communicated water inlet channel between the fan-shaped partition and the water inlet chamber;

[0015] Membrane filaments, filled in the fan-shaped partition, and the inner cavity of the membrane filaments is communicated with the water outlet chamber.

[0016] Preferably, the spacer plate is a rigid spacer plate, and the spacer plate is fixedly connected to the housing and / or the support rod.

[0017] Preferably, the spacer plate and the support rod are of an integrally formed structure, and the spacer plates are arranged in an annular array around the center line of the support rod.

[0018] Preferably, the surface of the spacer plate is provided with water permeable holes, and the water permeable holes are used to communicate adjacent two groups of the fan-shaped partitions.

[0019] Preferably, the filtration chamber is communicated with a sewage outlet, and the sewage outlet is communicated with all the fan-shaped partitions.

[0020] Preferably, the sewage outlet is at one end of the filtration chamber close to the water outlet chamber.

[0021] Preferably, the end sealant includes an epoxy resin sealing plate layer and a silicone rubber sealant layer; the silicone rubber sealant layer is close to the filtration chamber and is used to shield and seal the joint between the end sealant and the inner wall of the housing.

[0022] A sealing ring is arranged between the contact surface of the epoxy resin sealing plate layer and the inner wall of the housing.

[0023] Preferably, the support rod penetrates through the silicone rubber sealant layer and is fixedly installed with the epoxy resin sealing plate layer.

[0024] Preferably, the housing includes a barrel body and end caps at both ends. The end sealants are arranged at both ends of the barrel body, and a support frame for abutting against the end sealants is arranged inside the end caps.

[0025] An ultrafiltration device includes the external pressure type ultrafiltration membrane module described in any one of the above.

[0026] Compared with the prior art, the external pressure type ultrafiltration membrane module provided by the present utility model has at least the following beneficial effects:

[0027] 1. In this application, a support rod is used instead of the traditional central tube for water distribution. The two ends of the support rod are fixedly installed with the end sealant, which plays a role in supporting the membrane module and the membrane filaments. Using its own rigidity, it ensures the structural stability of the membrane module.

[0028] 2. In the housing, a fan-shaped partition arrangement is adopted, changing the end water distribution into a dispersed water distribution, reducing the water distribution dead angle near the water inlet end, reducing the water inlet speed and pressure at the water inlet end, being beneficial to balancing the water production resistance at each position in the axial direction of the housing, making the pressure bearing and the pollution rate of the membrane module balanced, and prolonging the effective working time of the membrane module.

[0029] 3. Adopting the fan-shaped partition helps the gas phase to be evenly distributed during the air scrubbing process, is beneficial to scrubbing the working surface of the membrane filaments in the membrane module, slows down the pollution of the membrane, and prolongs the service life of the membrane.

[0030] 4. At the same time, setting the fan-shaped partition can make the membrane filaments evenly distributed and filled in the module, and has a higher filling density compared with the traditional module, thereby improving the overall water production efficiency of the membrane module.

[0031] The ultrafiltration device provided by the present utility model includes the above-mentioned external pressure type ultrafiltration membrane module and has the same beneficial effects. Description of the Drawings

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0033] Figure 1 It is the front view of the specific external pressure ultrafiltration membrane module provided by the present invention;

[0034] Figure 2 It is the sectional view of the specific external pressure ultrafiltration membrane module provided by the present invention;

[0035] Figure 3 It is the schematic axial sectional view of the specific external pressure ultrafiltration membrane module provided by the present invention;

[0036] Figure 4 Provided by the present invention Figure 2 The enlarged view of part A in it.

[0037] Figures 1-4 In which:

[0038] 1. Housing; 101. Barrel body; 102. End cover; 103. Water inlet; 104. Water outlet; 105. Drain port; 106. Filter cavity; 107. Water inlet cavity; 108. Water outlet cavity;

[0039] 2. Support rod;

[0040] 3. Membrane filaments;

[0041] 4. End sealing glue; 401. Epoxy resin sealing plate layer; 402. Silicone sealing glue layer; 403. Sealing ring; 404. Water inlet channel;

[0042] 5. Spacer;

[0043] 6. Support frame. Detailed implementation manners

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0045] The core of the present utility model is to provide an external pressure ultrafiltration membrane module. By adding a support rod in the center of the housing, the stability of the membrane module is increased. And through the spacer plate, the inner wall of the housing is divided into fan-shaped partitions, so that the water distribution in the housing is dispersed, reducing the dead angle of water distribution. At the same time, the pressure bearing at different positions of the membrane module is balanced, slowing down the fouling of the membrane module. At the same time, it is beneficial to the uniform distribution of the gas phase during the air scrubbing process, ensuring the cleaning effect of the air scrubbing on the membrane module.

[0046] Another core of the present utility model is to provide an ultrafiltration device including the above-mentioned external pressure ultrafiltration membrane module, which has the same technical features and can achieve the same purpose.

[0047] Please refer to Figures 1-4 , an external pressure ultrafiltration membrane module, comprising:

[0048] A housing 1, which is cylindrical. Inside, it is sequentially divided into a water inlet chamber 107, a filtration chamber 106, and a water outlet chamber 108 by two groups of end sealants 4. A water inlet 103 is connected and arranged in the water inlet chamber 107, and a water outlet 104 is connected and arranged in the water outlet chamber 108;

[0049] A support rod 2, which is arranged in the filtration chamber 106. The support rod 2 overlaps with the center line of the housing 1, and both ends of the support rod 2 are fixedly connected to the end sealant 4;

[0050] Spacer plates 5, at least two groups, and are arranged in the filtration chamber 106, dividing the filtration chamber 106 into several groups of fan-shaped partitions. There is a communicating water inlet channel 404 between the fan-shaped partitions and the water inlet chamber 107;

[0051] Membrane filaments 3, which are filled in the fan-shaped partitions. The inner cavity of the membrane filaments 3 is communicated with the water outlet chamber 108.

[0052] When the external pressure ultrafiltration membrane module is in use, the raw water enters the inner cavity of the housing 1 through the water inlet 103. Under the action of pressure, it passes through the tube wall of the membrane filaments 3 for filtration. The impurities adhere to the outer wall of the tube wall of the membrane filaments 3, while the pure water flows through the inner cavity of the membrane filaments 3 to the water outlet 104 and is discharged. During the whole filtration process, a relatively large positive pressure needs to be maintained in the inner cavity of the housing 1 to promote the rapid passage of the raw water through the tube wall of the membrane filaments 3. This requires that the end sealant 4 used for sealing at the ends of the housing 1 has good sealing performance. By adding a support rod 2 at the center line position of the housing 1, and the support rod 2 is fixedly connected to the end sealants 4 at both ends, to ensure that when the internal pressure of the housing 1 increases, the end sealants 4 at both ends will not move towards both ends in the form of a piston, that is, to keep the end sealants 4 at both ends in a better relative position relationship, thereby ensuring the stability of the membrane module. In some embodiments, a hollow tube is used as the support rod 2, and the main force it bears is axial tension. Therefore, it is also feasible to use a hollow tube as the support rod 2, which also belongs to the protection scope of this application;

[0053] However, in this application, water enters through the water inlet 103 at the end. Compared with the hollow tube of the support rod 2 for water distribution, it helps to improve the overall rigidity and tensile resistance of the support rod 2, and effectively improves the overall stability of the membrane module;

[0054] However, when water enters through the water inlet 103 at the end, when the length of the membrane filaments 3 is relatively long, there will be a problem of increased water production resistance along the axis in the tube side of the housing 1, that is, the water flow velocity and water pressure of the water flow far from the end near the water inlet 103 are greater than those at the other end, and there is an easy occurrence of dead water areas for water distribution near the water inlet 103, resulting in uneven pressure on the tube walls of the membrane filaments 3, different water production efficiencies, uneven pollution on the surface of the membrane filaments 3, and accelerating the pollution process of the membrane;

[0055] Therefore, the spacer plate 5 is adopted to divide the inside of the housing 1 into several fan-shaped partitions arranged around the support rod 2 to achieve decentralized water distribution, thereby reducing the dead water areas for water distribution near the water inlet 103, and reducing the water inlet speed and pressure at the end near the water inlet 103, which helps to balance the pressure and flow velocity at different positions in the housing 1, that is, to ensure balanced water production at different positions of the membrane filaments 3, balanced surface pollution, delay the overall pollution process of the membrane, and extend the service life of the membrane filaments 3;

[0056] At the same time, during the air scrubbing process, the fan-shaped partition structure helps to evenly distribute the gas phase, which is beneficial to the scrubbing of the surface of the membrane filaments 3, thereby slowing down the pollution of the surface of the membrane filaments 3 and extending the overall life of the membrane module;

[0057] Moreover, through the fan-shaped partitions set by the spacer plate 5, the membrane filaments 3 can be evenly distributed in the housing 1, and the packing density is increased, thereby increasing the effective filtration area in the membrane module, and further improving the water production efficiency.

[0058] In some embodiments, the spacer plate 5 is a rigid partition, and the spacer plate 5 is fixedly connected to the housing 1 and / or the support rod 2;

[0059] During the design, the spacer plate 5 is designed independently, that is, insertion slots are provided on the inner wall of the housing 1 and / or the outer wall of the support rod 2 for the spacer plate 5 to be inserted and fixed, so as to divide the inside of the housing 1 to form fan-shaped partitions; during the actual design, in some embodiments, affected by the shape of the housing 1, the included angles between different spacer plates 5 are different, resulting in different sizes of fan-shaped partitions, but it still belongs to the protection scope of this application.

[0060] In some embodiments, the spacer plate 5 and the support rod 2 are of an integrally formed structure, and the spacer plate 5 is arranged in a circular array around the center line of the support rod 2;

[0061] The integrally formed spacer 5 and support rod 2 are assembled with the housing 1 together, which helps to reduce the assembly steps. Moreover, the spacer 5 increases the radial support for the support rod 2. Compared with the design of independent spacers 5, the integrally formed spacer 5 and support rod 2 are more conducive to ensuring the stability of the relative position relationship between different spacers 5 and avoiding the flexural deformation of the support rod 2, that is, ensuring the stability of the volume of each fan-shaped partition. During use, when there is a pressure difference in different fan-shaped partitions, the spacer 5 will not undergo displacement changes, which helps to ensure the overall stability of the membrane module. At the same time, as Figure 3 shown, the spacer 5 is arranged in a circular array around the support rod 2, which makes the sizes of all fan-shaped partitions the same, helps to reduce the pressure difference between each fan-shaped partition, so that the forces on both sides of the spacer 5 are balanced. Preferably, the number of fan-shaped partitions is 5 - 18.

[0062] In some embodiments, water permeable holes are provided on the surface of the spacer 5, and the water permeable holes are used to connect adjacent groups of fan-shaped partitions;

[0063] By providing water permeable holes on the surface of the spacer 5 to balance the pressure difference on both sides of the spacer 5, so that the forces on both sides of the spacer 5 are balanced and the overall stability of the membrane module is ensured. In actual design, the water permeable holes should be designed at one end close to the water outlet 104 to reduce the influence of the water permeable holes on the water distribution at the water inlet 103.

[0064] In some embodiments, as Figure 1 shown, a sewage outlet 105 is connected to the filtration chamber 106, and the sewage outlet 105 is connected to all fan-shaped partitions;

[0065] The sewage outlet 105 is located at one end of the filtration chamber 106 close to the water outlet chamber 108;

[0066] By providing the sewage outlet 105 close to the water outlet chamber 108, the wastewater and waste gas generated by air scrubbing are quickly discharged, and it is avoided that some wastewater and waste gas accumulate in the filtration chamber 106 for a long time, resulting in an increase in the amount of water used for flushing, so as to save water and improve the overall service life of the membrane module.

[0067] In some embodiments, the end sealant 4 includes an epoxy resin sealing plate layer 401 and a silicone rubber sealing layer 402; the silicone rubber sealing layer 402 is close to the filtration chamber 106 and is used to shield and seal the joint between the end sealant 4 and the inner wall of the housing 1;

[0068] A sealing ring 403 is provided between the contact surface of the epoxy resin sealing plate layer 401 and the inner wall of the housing 1;

[0069] As Figure 4As shown, a rigid epoxy resin sealing plate layer 401 is used as the base layer. The preferred thickness of the epoxy resin sealing plate layer 401 is 40 - 80 mm to ensure the stability of the shape of the end sealant 4. And by adding an annular sealing ring 403 on its outer periphery, the sealing performance between the epoxy resin sealing plate layer 401 and the inner wall of the housing 1 is improved;

[0070] At the same time, a soft silicone rubber sealant layer 402 is attached to the inner wall of the epoxy resin sealing plate layer 401. The preferred thickness of the silicone rubber sealant layer 402 is 10 - 30 mm, which further improves the sealing performance of the end sealant 4 and helps to increase the sealing performance at the position where the inner membrane filaments 3 penetrate through the end sealant 4. At the other end, the position where the membrane filaments 3 contact is covered by the soft silicone rubber sealant layer 402, which helps to slow down the wear of the membrane filaments 3 and extend the service life of the membrane filaments 3. At the same time, the end of the partition plate 5 directly abuts against the silicone rubber sealant layer 402, and the soft silicone rubber sealant layer 402 helps to increase the resistance when the partition plate 5 displaces, thus avoiding the deformation of its end.

[0071] The support rod 2 penetrates through the silicone rubber sealant layer 402 and is fixedly installed with the epoxy resin sealing plate layer 401;

[0072] The support rod 2 is fixed to the rigid epoxy resin sealing plate layer 401 to support the epoxy resin sealing plate layers 401 at both ends, thereby ensuring the stability of the relative position relationship of the end sealants 4 at both ends, that is, reducing the influence of the internal pressure in the filtration chamber 106 on the actual volume.

[0073] In some embodiments, as Figure 2 shown, the housing 1 includes a barrel body 101 and end caps 102 at both ends. The end sealants 4 are arranged at both ends of the barrel body 101, and a support frame 6 for abutting against the end sealants 4 is provided inside the end caps 102;

[0074] The housing 1 adopts a split design of the barrel body 101 and the end caps 102, which is convenient for filling the internal membrane filaments 3. And a support frame 6 is arranged inside the inner end cap 102 for abutting against the end sealants 4, thereby restricting the installation position of the combination of the end sealants 4 and the support rod 2, that is, ensuring the stability of the relative position between the membrane filaments 3 and the housing 1.

[0075] In addition to the external pressure type ultrafiltration membrane module disclosed in each of the above embodiments, the present invention also provides an ultrafiltration device including the above external pressure type ultrafiltration membrane module. Among them, the housing 1 preferably adopts a stainless steel housing, the support rod 2 preferably adopts a stainless steel hollow tube, the membrane filaments 3 preferably adopt polysulfone hollow fiber membrane filaments, and the preferred pore diameter of the membrane filaments 3 is 0.01 - 0.08 microns. For the structures of other parts of the ultrafiltration device, please refer to the prior art and will not be elaborated herein.

[0076] Compared with the existing products, which use PVC or ABS plastics as the housing 1 and the support rod 2, stainless steel has the advantages of durability, anti-pollution, etc., making the ultrafiltration equipment and the external pressure type ultrafiltration membrane module applicable to fields such as food and beverage, and medicine.

[0077] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0078] The above has introduced the external pressure type ultrafiltration membrane module provided by the present utility model in detail. Specific examples are used herein to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present utility model, several improvements and modifications can still be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. An external pressure ultrafiltration membrane module, characterized in that Comprising: A housing (1), which is cylindrical. Inside, it is successively divided into a water inlet chamber (107), a filtration chamber (106), and a water outlet chamber (108) by two groups of end sealants (4). The water inlet chamber (107) is communicatively provided with a water inlet (103), and the water outlet chamber (108) is communicatively provided with a water outlet (104); A support rod (2), arranged in the filtration chamber (106). The support rod (2) overlaps with the center line of the housing (1), and both ends of the support rod (2) are fixedly connected to the end sealant (4); Spacer plates (5), at least two groups, and arranged in the filtration chamber (106). The filtration chamber (106) is divided into several groups of fan-shaped partitions. There is a communicating water inlet channel (404) between the fan-shaped partitions and the water inlet chamber (107); Membrane filaments (3), filled in the fan-shaped partitions. The inner cavity of the membrane filaments (3) is communicatively connected to the water outlet chamber (108).

2. The external pressure ultrafiltration membrane module according to claim 1, wherein, The spacer plate (5) is a rigid spacer plate, and the spacer plate (5) is fixedly connected to the housing (1) and / or the support rod (2).

3. The external pressure type ultrafiltration membrane module according to claim 1, characterized in that, The spacer plate (5) and the support rod (2) are of an integrally formed structure, and the spacer plates (5) are arranged in a circular array around the center line of the support rod (2).

4. The external pressure type ultrafiltration membrane module according to claim 1, characterized in that, The surface of the spacer plate (5) is provided with water permeable holes, and the water permeable holes are used to communicate adjacent two groups of the fan-shaped partitions.

5. The external pressure ultrafiltration membrane module according to claim 1, characterized in that The filtration chamber (106) is communicatively provided with a sewage outlet (105), and the sewage outlet (105) communicates with all the fan-shaped partitions.

6. The external pressure type ultrafiltration membrane module according to claim 5, wherein The sewage outlet (105) is located at one end of the filtration chamber (106) close to the water outlet chamber (108).

7. The external pressure ultrafiltration membrane module according to claim 1, characterized in that, The end sealant (4) includes an epoxy resin sealing plate layer (401) and a silica gel sealant layer (402); the silica gel sealant layer (402) is close to the filtration chamber (106) and is used to shield and seal the joint between the end sealant (4) and the inner wall of the housing (1); A sealing ring (403) is arranged between the contact surface of the epoxy resin sealing plate layer (401) and the inner wall of the housing (1).

8. The external pressure type ultrafiltration membrane module according to claim 7, characterized in that, The support rod (2) penetrates through the silica gel sealant layer (402) and is fixedly installed with the epoxy resin sealing plate layer (401).

9. The external pressure ultrafiltration membrane module according to any one of claims 1-8, characterized in that, The housing (1) includes a barrel body (101) and end covers (102) at both ends. The end sealants (4) are arranged at both ends of the barrel body (101), and a support frame (6) for abutting against the end sealants (4) is arranged inside the end covers (102).

10. An ultrafiltration device, characterized in that, An external pressure type ultrafiltration membrane module according to any one of claims 1-9.

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