A filter element, a preparation method thereof, and a water filter jug

Abstract

The present invention provides a filter element, a preparation method thereof and a water filter jug. The filter element includes a protective shell and a filter element body located inside the protective shell. The protective shell includes a cover body and a shell body. Flow holes are provided on the cover body and the shell body. The filter element body includes: a first adsorption layer, which is a coarse filtration layer. The adsorbent particles in the first adsorption layer include ion exchange resin, and the particle size of the ion exchange resin is 0.25 - 3 mm; a first filter membrane, which is arranged between the first adsorption layer and the cover body, and the mesh number of the pores on the first filter membrane is 60 - 250 meshes; a second adsorption layer, which is stacked on one end face of the first adsorption layer away from the first filter membrane. The second adsorption layer is a fine filtration layer, and the adsorbent in the second adsorption layer includes the following components in weight ratio: 30 - 90% of activated carbon and 10 - 70% of heavy metal adsorbent. When the lead spiking concentration of the filter element is continuously spiked at 150 ± 10 ppb, the lead removal rate > 96.7%.

Description

Technical Field

[0001] The present invention relates to the field of water purification filtration, and particularly relates to a filter element, a preparation method thereof, and a water filter kettle. Background Art

[0002] In the existing water filter kettle filter elements, activated carbon and resin are often used to physically and chemically adsorb and remove impurities in water. However, most of them are loose filter materials directly filled with activated carbon and resin in the filter element housing. The water purification ability of the filter element with this structure is relatively limited, the removal rate of heavy metals and calcium and magnesium ions is relatively low, and due to the selection of large-particle loose filter materials, the overall filtration accuracy of the filter element is very low, and there is no removal effect on smaller particles such as colloids. It is also difficult for the existing water filter kettle filter elements to ensure good filtration performance at a certain water outlet flow rate.

[0003] Currently, the household water filter kettle filter elements also have the situation of low efficiency and high cost in the performance of removing heavy metals. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art, and provides a filter element, a preparation method thereof, and a water filter kettle to achieve better filtration performance at a higher water purification rate.

[0005] In order to achieve the above and other purposes, the present invention is realized by including the following technical solutions: The present invention first provides a filter element, the filter element includes a protective shell and a filter element body located inside the protective shell, the protective shell includes a cover body and a shell body, and flow holes are provided on the cover body and the shell body. Wherein the filter element body includes: a first adsorption layer, the first adsorption layer is a coarse filtration layer, the thickness of the first adsorption layer is h2, the adsorbent particles in the first adsorption layer include ion exchange resin, and the particle size of the ion exchange resin is 0.25 - 3 mm; a first filter membrane, arranged between the first adsorption layer and the cover body, the height between the first filter membrane and the first adsorption layer is h1, and the mesh number of the pores on the first filter membrane is 60 - 250 meshes; a second adsorption layer, stacked on one end face of the first adsorption layer away from the first filter membrane, the second adsorption layer is a fine filtration layer, and the adsorbent in the second adsorption layer includes the following components in weight ratio: 30 - 90% of activated carbon, 10 - 70% of heavy metal adsorbent, the thickness of the second adsorption layer is h3, the particle size of the activated carbon in the second adsorption layer is 0.15 - 0.6 mm, and the particle size of the heavy metal adsorbent is 0.075 - 0.3 mm;

[0006] Wherein: h1, h2, and h3 satisfy the following relational formula:

[0007] 1 / 10h3 < h1 < h3;

[0008] 1 / 4h3 < h2 < 2h3.

[0009] The present invention also provides a method for preparing a filter element, and the preparation method includes:

[0010] Providing a second adsorption layer;

[0011] Forming a first adsorption layer on the second adsorption layer;

[0012] Forming a first filter membrane on the first adsorption layer;

[0013] Placing the filter element body into the housing and closing the cover body.

[0014] The present invention also provides a water filter jug, and the water filter jug is loaded with the filter element as described above.

[0015] As described above, a filter element provided by the present invention has the following beneficial effects: The filter element of the present invention can achieve a total net water volume (lifetime) of 500 L under the operating conditions of high flow rate (150 - 350 mL / min), and when the lead spike concentration is continuously spiked at 150 ± 10 ppb, the lead removal rate is greater than 96.7% (meeting the NSF53 standard). At the same time, it also has good removal rates for residual chlorine and calcium and magnesium ions, and the filtration accuracy can reach 1 μm. On the premise of ensuring good filtration performance, the waiting time for users is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It shows a schematic structural view of the water filter jug of the present invention.

[0017] Figure 2 It shows a schematic structural view of the filter element of the present invention.

[0018] Figure 3 It shows a bottom view of the protective housing cover of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0020] As Figure 1As shown in the figure, the filter element 100 of the present invention is a filtering structure in a household water filter jug. The household water filter jug uses gravity filtration without adding external pressure additionally. The capacity of the water filter jug provided by the present invention can be 1 to 5 L, for example, 2 L. The water filter jug may include a jug body 1, a jug lid 3, a funnel 2, a handle 4, and a filter element 100. The jug body 1 has a receiving cavity with an opening at one end. The handle 4 can be arranged on one side of the jug body 1 for convenient grasping of the water filter jug. The funnel 2 can be located in the receiving cavity. The funnel 2 can divide the receiving cavity into a raw water area 1a and a purified water area 1b. The filter element 100 can be placed at the bottom of the funnel 2 to filter the raw water. The height between the filter element 100 and the top of the funnel 2 can be 70 to 150 mm, for example, 90 mm, 100 mm, 110 mm, etc. The jug lid 3 can cover the jug body 1. When in use, tap water (raw water) is poured into the funnel. The raw water is filtered by the filter element 100 and enters the purified water area 1b of the jug body 1. The water entering the purified water area 1b can be poured out through the through hole on the jug lid 3, which is convenient for subsequent heating or direct drinking.

[0021] As Figure 2 As shown in the figure, the present invention provides a filter element 100. In some embodiments, the overall height of the filter element 100 can be 15 to 60 mm, for example, 20 mm, 25 mm, 28 mm, 30 mm, 40 mm, 50 mm. The filter element 100 may include a protective shell, and the protective shell may include a shell body 100a and a cover body 100b. The cover body 100b can cover the shell body 100a. The filter element 100 may include a filter element body 100c, and the filter element body 100c can be entirely placed in the inner cavity of the shell body 100a. The shape of the filter element body 100c is adapted to the inner cavity of the shell body 100a. Further, flow holes A are provided at the bottom of the shell body 100a and on the cover body 100b to facilitate the outflow of raw water and purified water. The area of the flow hole A on the cover body 100b can be between 1 / 10 and 1 / 2 of the total cross-sectional area of the cover body 100b, for example, 1 / 3. Further, the aperture of the flow hole A can be greater than 10 mm.

[0022] The shape of the protective shell of the filter element 100 of the present invention is not limited. For example, the cross-section of the shell body 100a and the cross-section of the filter element body 100c can maintain the same shape.

[0023] As Figure 2As shown, further, a sealing ring S is also provided between the housing 100a and the cover 100b. The material of the sealing ring S can be silicone, TPU, EPDM, etc. The sealing ring S can ensure that the raw water entering the filter element 100 will not leak out and can all flow out after being purified through the flow holes (not shown in the figure) at the bottom of the housing 100a.

[0024] As Figure 2 shown, the filter element body 100 includes a first filter membrane 101. The first filter membrane 101 can be disposed between the cover 100b and the first adsorption layer 102, for example, fixed in the inner cavity of the housing 100a. In some embodiments, the first filter membrane 101 can be disposed on the cover 100b, for example, can be disposed on the inner cover wall of the cover 100b and cover the flow hole A. The sealing ring S can bond and connect the first filter membrane 101 and the cover 100b together and play a role in sealing the filter element 100. As Figure 2 shown, the first filter membrane 101 can be a kind of mesh cloth. The first filter membrane 101 can perform primary filtration, for example, can intercept larger particles in tap water, such as rust, sediment, etc. The material of the first filter membrane 101 can be any one or a combination of polyethylene terephthalate (PET), polypropylene (PP), nylon, PVDF, PTFE, etc. Further, it can be a hydrophilic material, such as a hydrophilic polyethylene terephthalate (PET) filter membrane, so that it is easier to let water in. The mesh number of the first filter membrane 101 can be 60 to 250 meshes, such as 100 meshes, 200 meshes, etc. The first filter membrane 101 can also prevent the adsorbent in the adsorption layer from escaping. The first filter membrane 101 is not limited to a membrane structure and can also be a kind of layer pad structure.

[0025] As Figure 2 shown, the filter element body 100c includes a first adsorption layer 102. The first adsorption layer 102 can be a coarse filtration layer. The coarse filtration layer is mainly used to remove calcium and magnesium ions in water and reduce the total hardness of the raw water. The first adsorption layer 102 is filled with adsorbent particles. The first adsorption layer 102 can be formed by filling the adsorbent particles under the action of gravity. The first adsorption layer 102 is filled with ion exchange resin. In some embodiments, activated carbon can also be filled in the first adsorption layer 102. The weight ratio of the activated carbon in the first adsorption layer 102 is 5% to 10%, such as 6%, 8%, etc. In the present invention, by adding a small amount of activated carbon particles in the first adsorption layer 102, it can be avoided that the ion exchange resin sticks together at room temperature and cannot be dispersed, and it can also have a certain effect of removing residual chlorine.

[0026] As Figure 2As shown, the particle size of the activated carbon in the first adsorption layer 102 is 0.15 - 3 mm, further 0.8 - 3 mm, and still further 1 - 3 mm. The activated carbon material in the first adsorption layer 102 can be wood-based, fruit shell-based, coconut shell-based, coal-based, or activated carbon particles mixed with multiple materials. The iodine adsorption value of the activated carbon in the first adsorption layer 102 can be greater than 800 mg / g, for example, it can be greater than or equal to 1000 mg / g, and further it can be 1000 - 1200 mg / g. Specifically, in some embodiments, the activated carbon particles in the first adsorption layer 102 can be large-particle activated carbon, which can reduce the risk of the activated carbon particles being thrown up and blocking the first filter membrane 101.

[0027] As Figure 2 shown, the weight percentage of the ion exchange resin in the first adsorption layer 102 can be 90 - 95%, such as 92%, 93%, etc. The ion exchange resin can be used to reduce the total hardness of the raw water. The particle size of the ion exchange resin in the first adsorption layer 102 is 0.25 - 3 mm, further 0.5 - 3 mm, and still further 0.5 - 1.5 mm.

[0028] As Figure 2 shown, further, the thickness of the first adsorption layer 102 can be 2 mm - 30 mm, such as 5 mm, 10 mm, 15 mm, etc. The flow-through area of the first adsorption layer 102 can be 4500 - 20000 square millimeters, such as 8500 square millimeters, 10000 square millimeters. The flow-through area can be, for example, the cross-sectional area of the first adsorption layer 102. In some embodiments, the first adsorption layer 102 can be directly stacked with adsorbent particle bulk materials, or can be filled and formed by being wrapped in a mesh cloth or a plastic part. The pressure drop of the bulk material stacking is small, which can improve the overall filtration rate of the filter element 100.

[0029] As Figure 2 shown, the raw water that has been roughly filtered by the filter material particles in the first adsorption layer 102 has initially reduced the total hardness of the raw water. The ion exchange resin in the first adsorption layer 102 can be any one of strong acid type resin, weak acid type resin, and anion-cation resin. Further, it can be any one or more of H-type, K-type, Na-type, and Ag-type ion exchange resins. For example, it can be ion exchange resins produced by companies such as LANXESS, Dow, Zhengguang, and Purolite.

[0030] As Figure 2As shown, the filter element body 100c includes a second adsorption layer 103. The second adsorption layer 103 can be a fine filtration layer. The second adsorption layer 103 can be a high-efficiency filtration layer, which can perform fine filtration. For example, it can efficiently remove heavy metal ions, organic matter, disinfection by-products, and smaller particulate matters such as colloids in water. Among them, the thickness of the second adsorption layer 103 can be 7 - 13 mm, such as 8 mm, 10 mm, 12 mm, etc. The flow-through area of the second adsorption layer 103 can be 4500 - 20000 square millimeters. By adjusting the thickness and flow-through area of the second adsorption layer 103, the present invention can have a relatively high water outlet flow rate while ensuring a certain heavy metal removal rate, thereby improving the filtration efficiency of raw water. The flow-through areas of the first adsorption layer 102 and the second adsorption layer 103 can be the same.

[0031] As Figure 2 shown, the second adsorption layer 103 can be filled with activated carbon and heavy metal adsorbent particles. Further, the weight ratio of the activated carbon in the second adsorption layer 103 can be 30 - 90%. Based on the adsorbent particles in the second adsorption layer 103 being 100%, for example, 40%, 50%, 60%, 70%, etc. The activated carbon can be wooden, fruit shell, coconut shell, coal-based, or activated carbon particles of a mixture of multiple materials. The iodine adsorption value of the activated carbon can be greater than 800 mg / g, for example, it can be greater than or equal to 1000 mg / g, and further can be 1000 - 1200 mg / g. The particle size of the activated carbon can be 0.15 - 0.6 mm, and further can be 0.15 - 0.425 mm. Further, the absolute value of the particle size difference between different adsorbents in the second adsorption layer 103 can be between 0.1 - 0.6 mm, and further can be between 0.1 - 0.5 mm. Keeping the particle size difference within a certain range can prevent the pores between the two types of particles from being too large or too small, which can ensure that the adsorbents in the second adsorption layer 103 have a certain density and can also ensure a certain net water flow rate. In some embodiments, the particle diameter of the adsorbent in the first adsorption layer 102 is larger than the particle diameter in the second adsorption layer 103.

[0032] As Figure 2 shown, the weight ratio of the heavy metal adsorbent in the second adsorption layer 103 is 10 - 70%, such as 20%, 30%, 40%, 50%, etc. The type of the heavy metal adsorbent can be any one or a combination of iron-based, activated carbon-based, titanium dioxide-based, silicon dioxide-based, molecular sieve, chitosan-based, polyacrylonitrile-based, polyacrylate-based, starch-based, cellulose-based, polystyrene divinyl. Further, it can be adsorbents produced by GRAVER and ATS. The particle size of the heavy metal adsorbent particles can be 0.075 - 0.3 mm.

[0033] As Figure 2 shown, by adjusting the particle sizes of the activated carbon and the heavy metal adsorbent in the second adsorption layer 103 of the present invention, a certain porosity can be achieved between different particles while maintaining good compactness. This can ensure that the obtained heavy metal filtration medium has good heavy metal adsorption performance and a high water purification rate.

[0034] As Figure 2 shown, further, the second adsorption layer 103 can be formed by sintering adsorbent particles added with a binder or filled with plastic parts of a fixed volume. Further, it can be sintered. The sintered second adsorption layer 103 can exist as a whole filter block, which is convenient to take and assemble subsequently, and effectively reduces the process cost of manufacturing the filter jug filter element to a certain extent.

[0035] As Figure 2 shown, in some embodiments, the second adsorption layer 103 includes a binder, and the binder can be a polyethylene material with a high melt index. The molecular weight of the polyethylene material can be 3 million to 6 million, such as 5 million. The weight ratio of the binder in the second adsorption layer can be 20% to 50%, such as 25%, 30%, 40%, etc.

[0036] As Figure 2 shown, the filter element body 100c further includes a second filter membrane 104. The second filter membrane 104 is disposed below the second adsorption layer 103. The structural material of the second filter membrane 104 can be the same as or different from that of the first filter membrane 101. The second filter membrane 104 can prevent the adsorbent particles in the filter element 100 from falling into the water purification area. The pore diameters of the pores on the first filter membrane 101 and the second filter membrane 104 can be less than or equal to the particle diameter of the adsorbent particles in the filter element body 100c to prevent the leakage of the adsorbent particles.

[0037] As Figure 2 shown, the filter element of the present invention needs to satisfy the following relational expressions:

[0038] 1 / 10h3 < h1 < h3;

[0039] 1 / 4h3 < h2 < 2h3.

[0040] The present invention defines the height between the first filter membrane 101 and the first adsorption layer 102 as h1, defines the thickness of the first adsorption layer 101 as h2, and defines the thickness of the second adsorption layer 103 as h3, where 1 / 10h3 < h1 < h3. This can leave a certain reserved space between the first filter membrane 101 and the first adsorption layer 102, which can not only avoid the problems caused by the expansion of ion exchange resin, but also provide enough compression space for the raw water to exchange volume to ensure the flow rate of the purified water. Further, h1 can be 2mm ≤ h1 ≤ 10mm, such as 3mm, 5mm, etc.

[0041] The present invention defines 1 / 4h3 < h2 < 2h3, which can ensure that the first adsorption layer 102 has a certain performance of removing calcium and magnesium ions, and can also avoid the problems caused by the too thick thickness of the first adsorption layer 102, such as the small reserved space of h1 and the poor exhaust effect and purified water effect caused by the insufficient thickness of h3. Further, h2 can be 2mm ≤ h2 ≤ 20mm, such as 8mm, 10mm, 15mm, etc., and h3 can be 7mm ≤ h3 ≤ 13mm, such as 8.5mm, 9mm, etc. The present invention defines the thickness of h3 so that the filter element 100 can simultaneously have good Pb removal performance and good purified water rate.

[0042] The present invention reserves an appropriate space h1 between the first filter membrane 101 and the first adsorption layer 102, and controls the first filter membrane 101 within a certain mesh number range, which can avoid the problem of the activated carbon particles in the first adsorption layer 102 in the filter element body 100c being directly impacted during the purified water process, resulting in the throwing up and blocking of the filter membrane. It can also reduce the risk of the smaller adsorbent particles in the second adsorption layer 103 overflowing the filter membrane, prevent the finer particles in the second adsorption layer 103 from being washed out of the filter element during the raw water purification process, and can also solve the common problem of poor exhaust of the filter element 100. The present invention does not need to separately design an exhaust hole on the cover body 100b, and there will be no problem of raw water overflow even when the water flow is large during the purified water process.

[0043] As Figure 2 and Figure 3 shown, the present invention also provides a preparation method of a filter element, and the method includes the following steps:

[0044] —S1: Provide a second adsorption layer;

[0045] —S2: Form a first adsorption layer on the second adsorption layer;

[0046] —S3: Form a first filter membrane on the first adsorption layer;

[0047] —S4: Place the filter element body into the shell, and close the cover body to form the filter element.

[0048] In step S1, the second adsorption layer 103 can be formed by sintering. Specifically, activated carbon, heavy metal adsorbent, and binder can be mixed and stirred. After being stirred evenly, the mixture is poured into a mold. After the mixture is naturally filled in the mold, the upper surface of the mixture is flattened, and the mold is heated. The mold is a metal mold, which can be an iron mold. The wall thickness of the mold can be 2 - 10 mm, such as 5 mm, 6 mm, 8 mm, etc. The heating temperature can be 150 - 250 degrees Celsius, and the heating time can be 30 - 120 min.

[0049] In the sintering process of the present invention, after the activated carbon and the heavy metal adsorbent are mixed evenly, the surface is flattened and directly heated, without being pressed by a separate pressure machine and then sintered. In this way, the second adsorption layer 103 obtained by sintering will be too dense, resulting in problems such as difficult outflow of raw water and too low net water flow rate. The heated sample is naturally cooled at room temperature to obtain the second adsorption layer 103. Specifically, the density of the second adsorption layer 103 prepared by the sintering process can be 0.35 - 1 g / cm³.

[0050] In step S1, the second adsorption layer 103 can also be directly filled with activated carbon and heavy metal adsorbent using a plastic part of a fixed volume.

[0051] In step S2, the loose material of the first adsorption layer 102 can be wrapped in a mesh cloth and laid on the second adsorption layer 103, or the loose adsorbent particles can be directly spread on the second adsorption layer 103 to form the first adsorption layer 102.

[0052] In steps S3 and S4, the first filter membrane 101 can be covered on the flow hole A on the inner wall of the cover body 100b through a sealing ring S, or can be directly fixed on the side wall of the inner cavity of the housing 100a.

[0053] In step S4, the filter element body 100c further includes a second filter membrane 104 disposed below the second adsorption layer 103.

[0054] Hereinafter, the present invention will be further described with reference to specific embodiments.

[0055] In the following embodiments and comparative examples, the particle sizes of the adsorbent particles are all composed of particles of different sizes mixed together. For example, the particle size of the activated carbon is 0.15 - 3 mm, which is composed of activated carbon particles with a minimum particle size of 0.15 mm to a maximum particle size of 3 mm, and the particle size distribution among them is a normal distribution.

[0056] Embodiment 1

[0057] First filtration membrane: PET hydrophilic filtration membrane, mesh number 250 (pore diameter 0.061 mm), h1 = 2 mm.

[0058] First adsorption layer: Activated carbon: particle size 0.15 - 3 mm, content 10%; ion exchange resin: particle size 0.25 - 3 mm, content 90%, h2 = 2 mm.

[0059] Second adsorption layer: Activated carbon: particle size 0.15 - 0.6 mm, content 70%, heavy metal adsorbent particle size 0.075 - 0.3 mm, content 10%, binder content 20%, h3 = 7 mm.

[0060] Second filtration membrane: PET hydrophilic filtration membrane, mesh number 250.

[0061] The flow - through area of the filter element in this embodiment is 20,000 square millimeters. The test results of the removal rates of residual chlorine, calcium and magnesium ions, lead and the filtration accuracy are shown in Table 1: The test method for the filtration accuracy is as follows: Mud powder with different particle sizes is mixed into water, and after being filtered by the filter element of the present invention, the particle size distribution of the particulate matter in the filtrate is measured.

[0062] Table 1 Residual chlorine, calcium and magnesium ions, lead removal rate

[0063]

[0064] Embodiment 2

[0065] First filtration membrane: PET hydrophilic filtration membrane, mesh number 250 (pore diameter 0.061 mm), h1 = 2 mm.

[0066] First adsorption layer: Activated carbon: particle size 0.15 - 3 mm, content 10%; ion exchange resin: particle size 0.25 - 3 mm, content 90%, h2 = 4 mm.

[0067] Second adsorption layer: Activated carbon: particle size 0.15 - 0.6 mm, content 70%, heavy metal adsorbent particle size 0.075 - 0.3 mm, content 10%, binder content 20%, h3 = 13 mm.

[0068] Second filtration membrane: PET hydrophilic filtration membrane, mesh number 250.

[0069] The flow - through area of the filter element in this embodiment is 4,500 square millimeters. The test results of the removal rates of residual chlorine, calcium and magnesium ions, lead and the filtration accuracy are shown in Table 2: The test method for the filtration accuracy is as follows: Mud powder with different particle sizes is mixed into water, and after being filtered by the filter element of the present invention, the particle size distribution of the particulate matter in the filtrate is measured.

[0070] Table 2 Residual chlorine, calcium and magnesium ions, lead removal rate

[0071]

[0072] Embodiment 3

[0073] First filter membrane: PET hydrophilic filter membrane, mesh number 60 (aperture about 0.25 mm), h1 = 10 mm.

[0074] First adsorption layer: Activated carbon: particle size 0.25 - 3 mm, content 10%; ion exchange resin: particle size 0.25 - 3 mm, content 90%, h2 = 20 mm.

[0075] Second adsorption layer: Activated carbon: particle size 0.15 - 0.6 mm, content 70%, heavy metal adsorbent particle size 0.075 - 0.3 mm, content 10%, binder content 20%, h3 = 13 mm.

[0076] Second filter membrane: PET hydrophilic filter membrane, mesh number 250.

[0077] The flow - through area of the filter element in this embodiment is 8500 square millimeters. The test results of the removal rates of residual chlorine, calcium and magnesium ions, lead and the filtration accuracy are shown in Table 3: The test method for the filtration accuracy is as follows: Mud powder with different particle sizes is mixed into water, and after being filtered by the filter element described in the present invention, the particle size distribution of the particulate matter in the filtrate is measured.

[0078] Table 3 Residual chlorine, calcium and magnesium ions, lead removal rate

[0079]

[0080] Embodiment 4

[0081] First filter membrane: PET hydrophilic filter membrane, mesh number 60 (aperture about 0.25 mm), h1 = 3 mm.

[0082] First adsorption layer: Activated carbon: particle size 0.25 - 3 mm, content 10%; ion exchange resin: particle size 0.25 - 3 mm, content 90%, h2 = 20 mm.

[0083] Second adsorption layer: Activated carbon: particle size 0.15 - 0.6 mm, content 70%, heavy metal adsorbent particle size 0.075 - 0.3 mm, content 10%, binder content 20%, h3 = 13 mm.

[0084] Second filter membrane: PET hydrophilic filter membrane, mesh number 250.

[0085] The cross-sectional area of the filter element in this embodiment is 4,500 square millimeters. The test results of the removal rates of residual chlorine, calcium and magnesium ions, lead, and the filtration accuracy are shown in Table 4. The test method for the filtration accuracy is as follows: Powders of different particle sizes are mixed into water, and after being filtered through the filter element of the present invention, the particle size distribution of the particulate matter in the filtrate is measured.

[0086] Table 4 Residual chlorine, calcium and magnesium ions, lead removal rate

[0087]

[0088] Comparative Example 1

[0089] The first filter membrane: a PET hydrophilic filter membrane with a mesh number of 250 (pore diameter 0.061 mm), h1 = 2 mm.

[0090] The first adsorption layer: activated carbon with a particle size of 0.15 - 3 mm and a content of 10%; ion exchange resin with a particle size of 0.25 - 3 mm and a content of 90%, h2 = 2 mm.

[0091] The second adsorption layer: activated carbon with a particle size of 0.04 - 0.2 mm and a content of 70%, heavy metal adsorbent with a particle size of 0.04 - 0.15 mm and a content of 10%, binder content of 20%, h3 = 7 mm.

[0092] The second filter membrane: a PET hydrophilic filter membrane with a mesh number of 250.

[0093] The cross-sectional area of the filter element in this comparative example is 4,500 square millimeters. The removal rates of residual chlorine, calcium and magnesium ions, lead, and the filtration accuracy were tested. During the raw water filtration experiment, it was found that due to the excessive density of the second adsorption layer, the purified water flowed down in a dripping state, making it a non-conforming product.

[0094] Comparative Example 2

[0095] The first filter membrane: a PET hydrophilic filter membrane with a mesh number of 250 (pore diameter 0.061 mm), h1 = 2 mm.

[0096] The first adsorption layer: activated carbon with a particle size of 0.15 - 3 mm and a content of 10%; ion exchange resin with a particle size of 0.25 - 3 mm and a content of 90%, h2 = 4 mm.

[0097] The second adsorption layer: activated carbon with a particle size of 0.15 - 0.6 mm and a content of 70%, heavy metal adsorbent with a particle size of 0.075 - 0.3 mm and a content of 10%, binder content of 20%, h3 = 15 mm.

[0098] The second filter membrane: a PET hydrophilic filter membrane with a mesh number of 250.

[0099] In this comparative example, the flow-through area of the filter element is 4,500 square millimeters. The removal rates of residual chlorine, calcium and magnesium ions, and lead, as well as the filtration accuracy, are tested. Since the thickness of the second adsorption layer is too large, the purified water flows down in a dripping state, so it is a substandard product.

[0100] Comparative Example 3

[0101] First filtration membrane: PET hydrophilic filtration membrane, mesh number 250 (pore diameter is about 0.061 mm), h1 = 1 mm.

[0102] First adsorption layer: activated carbon: particle size 0.15 - 3 mm, content 10%; ion exchange resin: particle size 0.25 - 3 mm, content 90%, h2 = 4 mm.

[0103] Second adsorption layer: activated carbon: particle size 0.15 - 0.6 mm, content 70%, heavy metal adsorbent particle size 0.075 - 0.3 mm, content 10%, binder content 20%, h3 = 13 mm.

[0104] Second filtration membrane: PET hydrophilic filtration membrane, mesh number 250.

[0105] In this comparative example, the flow-through area of the filter element is 4,500 square millimeters. The removal rates of residual chlorine, calcium and magnesium ions, and lead, as well as the filtration accuracy, are tested. During the raw water filtration experiment, it is found that the initial rate is 150 mL / min. When the volume of the purified water reaches 500 mL, the flow rate drops to 50 mL / min (dripping state). It can be seen that h1 is too small, resulting in difficult exhaust in the later stage and the raw water cannot be pressed into the filter element for purified water treatment.

[0106] Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value. The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing a filter element, characterized in that: the method comprises the following steps: providing a second adsorption layer; forming a first adsorption layer on the second adsorption layer; forming a first filter membrane on the first adsorption layer; placing the filter element body into a housing and covering the cover body to form the filter element; the filter element includes a protective housing and a filter element body located inside the protective housing, the protective housing includes a cover body and a housing, and flow holes are provided on the cover body and the housing, wherein the filter element body includes: a first adsorption layer, the first adsorption layer is a coarse filtration layer, the thickness of the first adsorption layer is h2, the adsorbent particles in the first adsorption layer include ion exchange resin, and the particle size of the ion exchange resin is 0.25 - 3 mm; a first filter membrane, disposed between the first adsorption layer and the cover body, the height between the first filter membrane and the first adsorption layer is h1, the mesh number of the pores on the first filter membrane is 60 - 250 meshes, the first filter membrane is a kind of mesh cloth, and the first filter membrane is disposed on the inner side wall of the cover body and covers the flow holes on the cover body; a second adsorption layer, stacked on one end face of the first adsorption layer away from the first filter membrane, the second adsorption layer is a fine filtration layer, and the adsorbent in the second adsorption layer includes the following components by weight ratio: 30 - 90% of activated carbon, 10 - 70% of heavy metal adsorbent; the thickness of the second adsorption layer is h3, the particle size of the activated carbon in the second adsorption layer is 0.15 - 0.6 mm, and the particle size of the heavy metal adsorbent is 0.075 - 0.3 mm; wherein: the value range of h3 is 7 mm ≤ h3 ≤ 13 mm, the value range of h2 is 2 mm ≤ h2 ≤ 20 mm, and h1, h2, and h3 satisfy the following relational expressions: 1 / 10h3 < h1 < h3; 1 / 4h3 < h2 < 2h3; the flow - through areas of the first adsorption layer and the second adsorption layer are 4500 - 20000 square millimeters, the first adsorption layer is a loose material layer, the second adsorption layer is sintered and formed, the second adsorption layer includes an adhesive, the density of the second adsorption layer is 0.35 - 1 g / cm³, and the sintering process includes any one or more of the following characteristics: (1) the wall thickness of the sintering mold is 2 - 10 mm; (2) the sintering temperature is 150 - 250 °C; (3) the sintering time is 30 - 120 min; the filter element includes any one or more of the following characteristics: (1) the iodine adsorption value of the activated carbon is greater than 800 mg / g; (2) the aperture of the flow hole on the cover body is greater than 10 mm, and the area of the flow hole on the cover body is between 1 / 10 and 1 / 2 of the total cross - sectional area of the cover body; (3) the adsorbent in the first adsorption layer is a mixed particle of ion exchange resin and activated carbon; (4) in the range of the purified water flow rate of 150 - 350 ml / min, when the lead spike concentration is continuously spiked at 150 ± 10 ppb, the lead removal rate > 96.7%, and the treatment capacity of the raw water reaches 200 - 500 L.

2. The method according to claim 1, wherein: the value range of h1 is 2 mm ≤ h1 ≤ 10 mm.

3. The method according to claim 1, wherein: the filter element body includes a second filter membrane, and the second filter membrane is disposed below the second adsorption layer.

4. A water filter jug, wherein: the water filter jug includes a filter element prepared by the method according to any one of claims 1 to 3.

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