Patent Description:
Conventional casing of a pump is formed of a metal. As a result, it is difficult to process the casing and manufacturing cost of the pump is very expensive.

<CIT> relates to an anticorrosion centrifugal pump, according to which a plastic layer with a certain thickness is compounded on a pump body by the plastic covering process, with an aim of improving the anticorrosion capacity of the external surface of a pump valve shell and the service life and the service environment.

<CIT> relates to a pump casing with a volute liner which is fabricated from a composite material including a fiberglass reinforced molded neoprene liner.

The above object of the present invention is achieved by the features defined in independent claim <NUM>. Further preferred features are set forth in dependent claims. To solve problem of the convention technique, the invention is to provide various casings capable of preventing distortion and a pump including the same.

A casing of a pump according to one embodiment of the invention includes a metal member configured to have at least two sub metal members; and a body. Here, the sub metal members are included in the body, and the body is formed of plastic. The casing protects an impeller of the pump, the sub metal members (<NUM>, <NUM>) surround the liner (<NUM>), a fluid flow space (<NUM>) through which fluid flows is formed in the liner (<NUM>), the liner (<NUM>) includes a liner body member (320a), a liner flange member (320c) and a liner connection member (320b, 320d) for connecting the liner body member (320a) to the liner flange member (320c), at least one of the sub metal members (<NUM>, <NUM>) includes a sub metal body member (330a, 332a), a sub metal flange member (330c) and a sub metal connection member (330b, 330d) for connecting the sub metal body member (330a, 332a) to the sub metal flange member (330c), the body includes a body member (<NUM>), a body flange member (<NUM>, <NUM>) and a body connection member (<NUM>, <NUM>) for connecting the body member (<NUM>) to the body flange member (<NUM>, <NUM>). A width of the sub metal flange member (330c) is higher than a width of the liner flange member (320c), and the sub metal flange member (330c) surrounds the liner connection member (320b, 320d) just beneath the liner flange member (320c). One of the sub metal members (<NUM>, <NUM>) surrounds a part of the body, and the other sub metal member (<NUM>, <NUM>) surrounds the other part of the body.

In a casing of a pump of the invention, a metal member is included in a body formed of plastic. Accordingly, distortion may not be occurred to the casing when the casing is combined with a piping.

Additionally, the casing of the invention is very excellent compared to a casing of a pump formed of plastic, in view of strength.

Example embodiments of the present invention will become more apparent by describing in detail example embodiments of the present invention with reference to the accompanying drawings, in which:.

The invention relates to a pump. In a casing of the pump, a metal member is included in a body formed of plastic. As a result, distortion of the casing may be prevented when the pump is combined with a piping.

A body of a casing of conventional pump is wholly formed of a metal. As a result, strength of the casing is excellent and distortion of the casing is prevented. However, it is difficult to process the casing to have desired shape and manufacturing cost of the pump is very expensive.

If the body is formed of only plastic, it is easy to process the casing and manufacturing cost of the casing is low. However, distortion may occur to the casing when the pump is combined with a piping, and so the casing may be broken down.

Accordingly, the invention provides various pumps including a casing capable of preventing distortion with easy processing and low manufacturing cost.

Hereinafter, various embodiments of the invention will be described in detail with reference to accompanying drawings.

<FIG> is a perspective view illustrating decomposition structure of a pump according to one embodiment of the invention, and <FIG> is a perspective view illustrating a pump according to one embodiment of the invention. <FIG> is a view illustrating decomposition structure of a casing according to one embodiment of the invention, <FIG> is a perspective view illustrating a casing according to one embodiment of the invention, <FIG> is a perspective view illustrating decomposition structure of a liner and a metal member, and <FIG> is a view illustrating decomposition structure of a casing of a pump according to another embodiment of the invention. A left structure in <FIG> shows combination structure of the liner and the metal member, and a right structure in <FIG> illustrates composition structure of a body, the liner and the metal member. A front structure in <FIG> shows decomposition structure of the liner and the metal member, and a rear structure in <FIG> illustrates composition structure of the body, the liner and the metal member.

In <FIG> and <FIG>, a pump of the present embodiment may include an impeller <NUM>, a casing <NUM>, a seal member <NUM>, a motor <NUM> and a shaft <NUM>.

The impeller <NUM> may deliver fluid inputted to a first fluid flow space 310a through a piping such as a pipe, etc. to a second fluid flow space 310b. Particularly, the impeller <NUM> may rotate in a specific velocity and deliver the fluid inputted to the first fluid flow space 310a up to a specific height of the second fluid flow space 310b in response to the rotating. Here, the specific height may depend on a rotation velocity of the impeller <NUM>.

The casing <NUM> protects the impeller <NUM> and may include the first fluid flow space 310a to which the fluid is inputted and the second fluid flow space 310b for delivering the fluid transferred through the first fluid flow space 310a to another piping. Here, the first fluid flow space 310a may cross over the second fluid flow space 310b.

In the casing <NUM>, a metal member is included in a plastic member. This will be described below.

The seal member <NUM> prevents the fluid transferred through the first fluid flow space 310a from being out flowed. Structure of the seal member <NUM> is not limited as in <FIG> but is variously modified as long as the seal member <NUM> prevents out flowing of the fluid.

The motor <NUM> rotates the impeller <NUM>. Particularly, an axis of the motor <NUM> is connected to a shaft <NUM>, and the shaft <NUM> is combined with the impeller <NUM>. As a result, the shaft <NUM> rotates when the axis of the motor <NUM> rotates, and the impeller <NUM> rotates in response to rotating of the shaft <NUM>.

Hereinafter, the casing <NUM> will be described in detail.

In <FIG> , the casing <NUM> of the pump of the present embodiment includes a body, a liner <NUM>, a metal member having a first sub metal member <NUM> and a second sub metal member <NUM> and a supporting member <NUM>.

The body includes a body member <NUM>, a first body connection member <NUM>, a first body flange member <NUM>, a second body connection member <NUM> and a second body flange member <NUM>.

In one embodiment, the body may be formed of a super engineering plastic or an engineering plastic. For example, the body may be made up of a polyphenylene ethers resin composition including a polyphenylene ethers resin and a polystyrene resin. Of course, the body may be formed of a polypropylene, a polyimide, a polysulfone, a poly phenylene sulfide, a polyamide imide, a polyacrylate, a polyether sulfone, a polyether ether ketone, a polyether imide, a liquid crystal polyester, a polyether ketone, etc. and their combination.

The body member <NUM> has for example a circular shape, but shape of the body member <NUM> is not limited as the circular shape.

The first body flange member <NUM> is connected to one end part of the body member <NUM> through the first body connection member <NUM> and may be combined with a flange of a piping.

In one embodiment, at least one hole may be formed on a first body flange member <NUM>, a hole may be formed on the flange of the piping, and the first body flange member <NUM> may be combined with the flange of the piping by passing a fixing member such as a bolt, etc. through the hole of the first body flange member <NUM> and the hole of the flange of the piping. As a result, the pump may be combined with the piping.

On the other hand, the pump may be combined with every device having a flange, and a combination process may be similar to above combination process.

The second body flange member <NUM> is connected to the other end part of the body member <NUM> through the second body connection member <NUM> and is combined with a piping. The combination process is similar to the combination process of the first body flange member <NUM>.

The liner <NUM> is formed in the body and has the same shape as the body or has a shape similar to the body.

In one embodiment, the liner <NUM> may be formed of a fluorine resin. The fluorine resin means every resin including fluorine in a molecule, and it includes a Polytetrafluoroethylene, PTFE, a Polychlorotrifluoroethylene PCTFE, a PolyVinyliDene Fluoride PVDF, a Fluorinated ethylene propylene FEP, an Ethyl Tetra Fluoro Ethylene ETFE or a Perfluoroalkoxy alkane PFA, etc. This fluorine resin has excellent heat resistance, excellent chemical resistance, excellent electric insulation, small friction coefficient, and does not have adhesion.

The liner <NUM> is in the body and it includes a liner body member 320a, a first liner connection member 320b, a first liner flange member 320c, a second liner connection member 320d and a second liner flange member 320e.

The first fluid flow space 310a through which the fluid flows is formed in the first liner flange member 320c, the first liner connection member 320b and the liner body member 320a, and the second fluid flow space 310b is formed in the second liner flange member 320e, the second liner connection member 320d and the liner body member 320a. That is, the fluid flow space <NUM> may include the first fluid flow space 310a and the second fluid flow space 310b. Accordingly, the fluid inputted to the first fluid flow space 310a may be outputted through the second fluid flow space 310b.

The first liner flange member 320c is disposed in the first body flange member <NUM>, and one side of the first liner flange member 320c may be exposed outside.

The second liner flange member 320e is disposed in the second body flange member <NUM>, and one side of the second liner flange member 320e may be exposed outside.

The metal member surrounds the liner <NUM> and is included in the body, as shown in <FIG> and <FIG>. Here, whole of the metal member is included in the body, and none part of the metal member may be exposed outside. That is, the liner <NUM> locates in the metal member, and the whole of the metal member may be included in the body.

The metal member includes a first sub metal member <NUM> and a second sub metal member <NUM>. For example, the metal member includes two sub metal members <NUM> and <NUM> with different shape. Here, the sub metal members <NUM> and <NUM> may be independent members.

The first sub metal member <NUM> may be in integral type, cover a part of the liner <NUM>, and include a first sub metal body member 330a, a <NUM>-<NUM> sub metal connection member 330b, a <NUM>-<NUM> sub metal flange member 330c, a <NUM>-<NUM> sub metal connection member 330d and a <NUM>-<NUM> sub metal flange member 330e.

The first sub metal body member 330a surrounds a part of the liner body member 320a and has a curved shape.

The <NUM>-<NUM> sub metal flange member 330c is connected to an end part of the first sub metal body member 330a through the <NUM>-<NUM> sub metal connection member 330b and close to the first liner flange member 320c while it is disposed just beneath the first liner flange member 320c. Particularly, a groove curve line formed at a center of the <NUM>-<NUM> sub metal flange member 330c may surround a part of the first liner connection member 320b just beneath the first liner flange member 320c, curvature of the groove curve line being the same as or similar to that of the first liner connection member 320b.

A width of the <NUM>-<NUM> sub metal flange member 330c is higher than that of the first liner flange member 320c. As a result, at least part of the <NUM>-<NUM> sub metal flange member 330c may be projected outside the first liner flange member 320c in a width direction when the <NUM>-<NUM> sub metal flange member 330c surrounds the first liner connection member 320b, as shown in <FIG>. Here, the first liner flange member 320c may be projected compared to the <NUM>-<NUM> sub metal flange member 330c in a longitudinal direction.

The <NUM>-<NUM> sub metal flange member 330c surrounds directly the first liner flange member 320c. In this case, the pump may have unstable structure because a space exists between the liner <NUM> and the metal member. Accordingly, it is effective that the <NUM>-<NUM> sub metal flange member 330c surrounds the first liner connection member 320b just beneath the first liner flange member 320c while the <NUM>-<NUM> sub metal flange member 330c closes to the first liner flange member 320c.

At least one hole may be formed on the <NUM>-<NUM> sub metal flange member 330c, a fixing member passing through the hole. That is, the fixing member passes the hole of the first body flange member <NUM> and the hole of the <NUM>-<NUM> sub metal flange member 330c when the pump is combined with the piping.

The <NUM>-<NUM> sub metal flange member 330e may be connected to the other end part of the first sub metal body member 330a through the <NUM>-<NUM> sub metal connection member 330d and close to the second liner flange member 320e while it is disposed just beneath the second liner flange member 320e. Particularly, a groove curve line formed at a center of the <NUM>-<NUM> sub metal flange member 330e may surround a part of the second liner connection member 320d just beneath the second liner flange member 320e, curvature of the groove curve line being the same as or similar to that of the second liner connection member 320d.

A width of the <NUM>-<NUM> sub metal flange member 330e is higher than that of the second liner flange member 320e. As a result, at least part of the <NUM>-<NUM> sub metal flange member 330e is projected outside the second liner flange member 320e in a width direction when the <NUM>-<NUM> sub metal flange member 330e surrounds the second liner connection member 320d, as shown in <FIG>. Here, the second liner flange member 320e is projected compared to the <NUM>-<NUM> sub metal flange member 330e in a longitudinal direction.

The <NUM>-<NUM> sub metal flange member 330e surrounds directly the second liner flange member 320e. In this case, the pump may have unstable structure because a space exists between the liner <NUM> and the metal member. Accordingly, it is effective that the <NUM>-<NUM> sub metal flange member 330e surrounds the second liner connection member 320d just beneath the second liner flange member 320e while the <NUM>-<NUM> sub metal flange member 330e closes to the second liner flange member 320e.

At least one hole may be formed on the <NUM>-<NUM> sub metal flange member 330e, a fixing member passing through the hole. That is, the fixing member passes the hole of the second body flange member <NUM> and the hole of the <NUM>-<NUM> sub metal flange member 330e when the pump is combined with the piping.

On the other hand, the <NUM>-<NUM> sub metal flange member 332c may have a shape of doughnuts cut by half, end sections except the groove curve line may be contacted with end sections of the <NUM>-<NUM> sub metal flange member 330c. That is, the metal member may surround the liner <NUM> while the end sections of the <NUM>-<NUM> sub metal flange member 330c are contacted with the end sections of the <NUM>-<NUM> sub metal flange member 332c. Here, the <NUM>-<NUM> sub metal flange member 330c has alsoma shape of doughnuts cut by half.

The second sub metal member <NUM> may be in integral type, cover the other part of the liner <NUM>, and include a second sub metal body member 332a, a <NUM>-<NUM> sub metal connection member 332b, a <NUM>-<NUM> sub metal flange member 332c, a <NUM>-<NUM> sub metal connection member 332d and a <NUM>-<NUM> sub metal flange member 332e.

The first sub metal member <NUM> surrounds a part of the liner <NUM>, and the second sub metal member <NUM> surrounds the other part of the liner <NUM>. That is, the sub metal members <NUM> and <NUM> surround the whole of the liner <NUM>.

The second sub metal body member 332a may surround the other part of the liner body member 320a and have a curved shape.

The <NUM>-<NUM> sub metal flange member 332c may be connected to an end part of the second sub metal body member 332a through the <NUM>-<NUM> sub metal connection member 332b and close to the first liner flange member 320c while it is disposed just beneath the first liner flange member 320c. Particularly, a groove curve line formed at a center of the <NUM>-<NUM> sub metal flange member 332c may surround a part of the first liner connection member 320b just beneath the first liner flange member 320c, curvature of the groove curve line being the same as or similar to that of the first liner connection member 320b.

The width of the <NUM>-<NUM> sub metal flange member 332c is higher than that of the first liner flange member 320c. As a result, at least part of the <NUM>-<NUM> sub metal flange member 332c is projected outside the first liner flange member 320c in a width direction when the <NUM>-<NUM> sub metal flange member 332c surrounds the first liner connection member 320b, as shown in <FIG>. Here, the first liner flange member 320c may be projected compared to the <NUM>-<NUM> sub metal flange member 332c in a longitudinal direction.

On the other hand, the <NUM>-<NUM> sub metal flange member 332c surrounds directly the first liner flange member 320c. In this case, the pump may have unstable structure because a space exists between the liner <NUM> and the metal member. Accordingly, it is effective that the <NUM>-<NUM> sub metal flange member 332c surrounds the first liner connection member 320b just beneath the first liner flange member 320c while the <NUM>-<NUM> sub metal flange member 332c closes to the first liner flange member 320c.

At least one hole may be formed on the <NUM>-<NUM> sub metal flange member 332c, a fixing member passing through the hole. That is, the fixing member passes the hole of the first body flange member <NUM> and the hole of the <NUM>-<NUM> sub metal flange member 332c when the pump is combined with the piping.

The <NUM>-<NUM> sub metal flange member 332e is connected to the other end part of the second sub metal body member 332a through the <NUM>-<NUM> sub metal connection member 332d and close to the second liner flange member 320e while it is disposed just beneath the second liner flange member 320e. Particularly, a groove curve line formed at a center of the <NUM>-<NUM> sub metal flange member 332e may surround a part of the second liner connection member 320d just beneath the second liner flange member 320e, curvature of the groove curve line being the same as or similar to that of the second liner connection member 320d.

The width of the <NUM>-<NUM> sub metal flange member 332e is higher than that of the second liner flange member 320e. As a result, at least part of the <NUM>-<NUM> sub metal flange member 332e is projected outside the second liner flange member 320e in a width direction when the <NUM>-<NUM> sub metal flange member 332e surrounds the second liner connection member 320d, as shown in <FIG>. Here, the second liner flange member 320e may be projected compared to the <NUM>-<NUM> sub metal flange member 332e in a longitudinal direction.

On the other hand, the <NUM>-<NUM> sub metal flange member 332e directly surrounds the second liner flange member 320e. In this case, the pump may have unstable structure because a space exists between the liner <NUM> and the metal member. Accordingly, it is effective that the <NUM>-<NUM> sub metal flange member 332e surrounds the second liner connection member 320d just beneath the second liner flange member 320e while the <NUM>-<NUM> sub metal flange member 332e closes to the second liner flange member 320e.

At least one hole may be formed on the <NUM>-<NUM> sub metal flange member 332e, a fixing member passing through the hole. That is, the fixing member passes the hole of the second body flange member <NUM> and the hole of the <NUM>-<NUM> sub metal flange member 332e when the pump is combined with the piping.

On the other hand, the <NUM>-<NUM> sub metal flange member 332e may have a shape of doughnuts cut by half, end sections except the groove curve line may be contacted with end sections of the <NUM>-<NUM> sub metal flange member 330e. That is, the metal member may surround the liner <NUM> while the end sections of the <NUM>-<NUM> sub metal flange member 330e are contacted with the end sections of the <NUM>-<NUM> sub metal flange member 332e. Here, the <NUM>-<NUM> sub metal flange member 330e has also a shape of doughnuts cut by half.

In a manufacture process, the metal member may be formed in the body by using an insert molding. Particularly, the metal member may be included in the body and the liner <NUM> may be formed in the metal member by insert-molding a structure where the sub metal members <NUM> and <NUM> surround the liner <NUM> in a plastic which is material of the body.

At least one hole other than the hole for the fixing member may be formed on the flange members 330c, 330e, 332c, 332e of the metal member, so that the metal member is fixed in the body. In this case, melt plastic fills the hole in the insert molding, and thus the metal member may be strongly combined in the body. However, a permeate preventing member (not shown) may be inserted into the hole for the fixing member so that the melt plastic is not filled in the hole, and then the permeate preventing member may be removed after the insert molding is completed.

One or more projection members may be formed on the metal member to more strongly combine the metal member in the body.

To use two separated sub metal members <NUM> and <NUM> is for locating the liner <NUM> in the metal member. It is impossible to insert the liner <NUM> in the metal member because a width of the flange member 320c or 320e of the liner <NUM> is greater than an inner space of the metal member, if the metal member is in a body. Accordingly, two separated sub metal members <NUM> and <NUM> are used to locate the liner <NUM> including the flange member 320c or 320e or the body member 320a higher than the inner space of the metal member in the metal member.

A supporting member <NUM> may support the body.

In one embodiment, the supporting member <NUM> may be wholly formed of metal or plastic and be longitudinally extended from a lower part of the body member <NUM> to support the body. In this case, the supporting member <NUM> may be combined with the body after it is independently manufactured.

In another embodiment, the supporting member <NUM> may include a metal supporting member 340a and a plastic supporting member 340b as shown in <FIG>.

The metal supporting member 340a may be longitudinally extended from a lower part of the sub metal member and be formed in a body with the sub metal member.

The plastic supporting member 340b may surround the metal supporting member 340a and be formed together with the metal supporting member 340a when the insert molding is performed. Here, plastic of the plastic supporting member 340b may be formed of above material.

Accordingly, a process of forming the supporting member <NUM> is simple, and the supporting member <NUM> may support the casing with adequate force.

Shortly, the sub metal members <NUM> and <NUM> may be included in the body formed of the plastic through the insert molding, while two sub metal members <NUM> and <NUM> surround the liner <NUM>. Here, the liner <NUM> may locate in the metal member.

Distortion may occur to the casing in a direction opposed to a fixed direction due to a fixing force of a fixing member when the flange of the casing is combined with a flange of the piping through the fixing member, if the body formed of plastic surrounds directly a liner and the metal member does not surround the liner.

Distortion may not occur or be minimized to the casing because the flange is strengthened though the flange of casing is combined with the flange of a piping through the fixing member, when the metal member is included in the body formed of the plastic while the liner <NUM> is disposed in the metal member.

Of course, distortion may be prevented when the casing is combined with the piping, if the body is formed of metal and the liner is included in the body. However, it is difficult to process the body and manufacturing cost of the casing may increase sharply. Additionally, corrosion may occur to the casing and lifetime of the casing may get shorter.

Accordingly, the body in the casing of the invention is formed of the plastic, wherein the metal member locates in the body to reinforce strength.

It is difficult to process precisely the metal member and it is easy to process precisely the plastic. The casing may have desired shape though the plastic is precisely processed without processing precisely the metal member, when the casing is manufactured. That is, the casing may be easily embodied to have desired shape with low manufacturing cost, and distortion may be minimized when the casing is combined with the piping.

On the other hand, the flange member of the liner <NUM>, the flange member of the metal member and the flange member of the body form a flange. In view of the flange, a metal member is included in a plastic. As a result, distortion may be minimized though the flange of the pump is combined with the flange of the piping.

In the above description, the metal member comprises two sub metal members <NUM> and <NUM>. However, the metal member may be formed with three or more sub metal members. Here, the liner <NUM> is disposed in the sub metal members and the sub metal members are included in the body. The sub metal members may have the same shape or at least one of the sub metal members may have different shape.

For example, three sub metal members, which are separately disposed by <NUM>° with the same shape, may surround the liner <NUM>. It is efficient that the metal member includes two sub metal members <NUM> and <NUM> in consideration of easiness of the process.

<FIG> is a view illustrating schematically section of a casing of a pump according to still another embodiment, which is not in accordance with the invention.

In <FIG>, a liner <NUM>, a resin layer <NUM>, a metal member <NUM> and a body <NUM> may be sequentially disposed.

That is, unlike other embodiments, in the present embodiment, the resin layer <NUM> may be disposed between the liner <NUM> and the metal member <NUM>.

In one embodiment, the resin layer <NUM> may be formed of the same material as the body <NUM>. The material of the body in the above embodiment may be used as the material of the body <NUM>.

If molding after inserting a structure where the sub metal members surround the liner <NUM> in a plastic corresponding to the material of the body <NUM> and the resin layer <NUM>, melted plastic permeates through a space between the liner <NUM> and the metal member <NUM> because a space exists between the sub metal members. As a result, the resin layer <NUM> may be formed between the liner <NUM> and the metal member <NUM>.

A hole may be formed on a part of the metal member <NUM> so that the melted plastic is easily permeated between the liner <NUM> and the metal member <NUM>.

The structure where the resin layer is formed between the liner and the metal member may be also applied to other embodiment.

Hereinafter, material of the body will be described in detail.

The body may be formed by mixing a glass fiber with a Polyvinyl Chloride PVC, a polypropylene PP, a Poly Phenylene sulfide PPS, a Polyphthalamide PPA, a Polyamide PA6, a Polyamide PA66, a Polyketone POK or a Polyethylene PE. As a result, strength, impact resistance and mechanical feature of the body may be enhanced.

In another embodiment, the body may be formed by mixing a glass fiber and a carbon fiber with for example, a PVC, a PP, a PPS, a PPA, a PA6, a PA66, a POK or a PE. Accordingly, strength, impact resistance and mechanical feature of the body may be enhanced.

In still another embodiment, the body may be formed by mixing a glass fiber, a carbon fiber and a graphite fiber with for example, a PVC, a PP, a PPS, a PPA, a PA6, a PA66, a POK or a PE. Here, composition of the glass fiber, the carbon fiber and graphite fiber may be <NUM>:<NUM>:<NUM>. As a result, strength, impact resistance and mechanical feature of the body may be enhanced.

Hereinafter, composition and an experimental result of the body will be described.

In one embodiment, the body may be formed by mixing a PP with a glass fiber. Preferably, the glass fiber has a weight percent higher than <NUM> weight percent and less than <NUM> weight percent, and the PP has a weight percent higher than <NUM> weight percent.

Experimental result is shown in following table <NUM>.

It is verified through the above table <NUM> that tensile strength of the body when the body is formed by mixing the PP with the glass fiber is very greater than that of a body formed of only the PP. That is, mechanical property and chemical property may be enhanced. However, it is difficult to manufacture the body to have desired shape because an insert molding feature for manufacturing the body is deteriorated when the glass fiber has a weight percent higher than <NUM> weight percent.

In another embodiment, the body may be formed by mixing a PPS with a glass fiber. Preferably, the glass fiber has a weight percent higher than <NUM> weight percent and less than <NUM> weight percent, and the PPS has a weight percent higher than <NUM> weight percent. Experimental result is shown in following table <NUM>.

It is verified through the above table <NUM> that tensile strength of the body when the body is formed by mixing the PPS with the glass fiber is very greater than that of a body formed of only the PPS. That is, mechanical property and chemical property may be enhanced, and thus light and strong body may be formed. However, it is difficult to manufacture the body to have desired shape because an insert molding feature for manufacturing the body is deteriorated when the glass fiber has a weight percent higher than <NUM> weight percent.

In still another embodiment, the body may be formed by mixing a PPA with a glass fiber. Preferably, the glass fiber has a weight percent higher than <NUM> weight percent and less than <NUM> weight percent, and the PPA has a weight percent higher than <NUM> weight percent. Experimental result is shown in following table <NUM>.

It is verified through the above table <NUM> that tensile strength of the body when the body is formed by mixing the PPA with the glass fiber is very greater than that of a body formed of only the PPA. That is, mechanical property and chemical property may be enhanced, and thus light and strong body may be formed. However, it is difficult to manufacture the body to have desired shape because an insert molding feature for manufacturing the body is deteriorated when the glass fiber has a weight percent higher than <NUM> weight percent.

In still another embodiment, the body may be formed by mixing a PA6 with a glass fiber. Preferably, the glass fiber has a weight percent higher than <NUM> weight percent and less than <NUM> weight percent, and the PA6 has a weight percent higher than <NUM> weight percent. Experimental result is shown in following table <NUM>.

It is verified through the above table <NUM> that tensile strength of the body when the body is formed by mixing the PA6 with the glass fiber is very greater than that of a body formed of only the PA6. That is, mechanical property and chemical property may be enhanced, and thus light and strong body may be formed. However, it is difficult to manufacture the body to have desired shape because an insert molding feature for manufacturing the body is deteriorated when the glass fiber has a weight percent higher than <NUM> weight percent.

In still another embodiment, the body may be formed by mixing a PA66 with a glass fiber. Preferably, the glass fiber has a weight percent higher than <NUM> weight percent and less than <NUM> weight percent, and the PA66 has a weight percent higher than <NUM> weight percent. Experimental result is shown in following table <NUM>.

It is verified through the above table <NUM> that tensile strength of the body when the body is formed by mixing the PA66 with the glass fiber is very greater than that of a body formed of only the PA66. That is, mechanical property and chemical property may be enhanced, and thus light and strong body may be formed. However, it is difficult to manufacture the body to have desired shape because an insert molding feature for manufacturing the body is deteriorated when the glass fiber has a weight percent higher than <NUM> weight percent.

In still another embodiment, the body may be formed by mixing a POK with a glass fiber. Preferably, the glass fiber has a weight percent higher than <NUM> weight percent and less than <NUM> weight percent, and the POK has a weight percent higher than <NUM> weight percent. Experimental result is shown in following table <NUM>.

It is verified through the above table <NUM> that tensile strength of the body when the body is formed by mixing the POK with the glass fiber is very greater than that of a body formed with only the POK. That is, mechanical property and chemical property may be enhanced, and thus light and strong body may be formed. However, it is difficult to manufacture the body to have desired shape because an insert molding feature for manufacturing the body is deteriorated when the glass fiber has a weight percent higher than <NUM> weight percent.

Claim 1:
A casing of a pump comprising:
a metal member configured to have at least two sub metal members (<NUM>, <NUM>);
a body; and
a liner (<NUM>),
wherein the sub metal members (<NUM>, <NUM>) are included in the body, and the body is formed of plastic,
characterized in that the casing protects an impeller of the pump, the sub metal members (<NUM>, <NUM>) surround the liner (<NUM>), a fluid flow space (<NUM>) through which fluid flows is formed in the liner (<NUM>), the liner (<NUM>) includes a liner body member (320a), a liner flange member (320c) and a liner connection member (320b, 320d) for connecting the liner body member (320a) to the liner flange member (320c), at least one of the sub metal members (<NUM>, <NUM>) includes a sub metal body member (330a, 332a), a sub metal flange member (330c) and a sub metal connection member (330b, 330d) for connecting the sub metal body member (330a, 332a) to the sub metal flange member (330c), the body includes a body member (<NUM>), a body flange member (<NUM>, <NUM>) and a body connection member (<NUM>, <NUM>) for connecting the body member (<NUM>) to the body flange member (<NUM>, <NUM>),
a width of the sub metal flange member (330c) is higher than a width of the liner flange member (320c), and the sub metal flange member (330c) surrounds the liner connection member (320b, 320d) just beneath the liner flange member (320c),
one of the sub metal members (<NUM>, <NUM>) surrounds a part of the body, and the other sub metal member (<NUM>, <NUM>) surrounds the other part of the body.