WO2014147644A2

WO2014147644A2 - Ripbac back washable strainer for separating solids from low-viscosity liquids

Info

Publication number: WO2014147644A2
Application number: PCT/IN2014/000166
Authority: WO
Inventors: Puddukarai Srinivasan RAMACHANDRAN
Original assignee: Ramachandran Puddukarai Srinivasan
Priority date: 2013-03-19
Filing date: 2014-03-14
Publication date: 2014-09-25
Also published as: WO2014147644A3; IN2013MU00827A

Abstract

A Strainer assembly having lower downtime, suitable for in let and outlet size lines ranging from 3" & above, comprising a removable filter element plate screen of bolted construction fixed at an angle of approximately 45° to the base of the body; the slanting angle maintained by means of an element mounting flange or guide channel; the element mounting flange/guide channel and the filtrate element being connected by means of a closure plate which seals the filtrate from mixing with the inlet fluid; the said filtrate element being cleaned by backwash facility once ΔΡ levels are reached; the said backwash cycle occurring by closure of both the inlet and outlet valves; the resultant slurry being drained through a reducer and expelled through a slurry drain nozzle; the said body comprising either a T arm or a manhole for facilitating removal of the filtrate element.

Description

RIPBAC BACK WASHABLE STRAINER FOR SEPARATING SOLIDS FROM LOW- VISCOSITY LIQUIDS

FIELD OF INVENTION:

[0001 ] The invention relates to a back washable Strainer to separate solid particles from water / low viscosity liquids. The invention aims at providing a Strainer which can be backwashed with minimum downtime and without manual intervention. The invention also takes into account cleaning operation through manual intervention to be done under abnormal working conditions when large size particles enter the filter.

BACKGROUND OF THE INVENTION

[0002] Separating suspended solids from low viscosity fluid using a Strainer has been cumbersome & tedious because strainers currently available occupy large footprint of space and face difficulty in installation in tightly enclosed spaces.

[0003] Most existing Strainers are designed in filtration system wherein the flow of the liquid is from in to out. Since the flow is from in to out, the strainer has to be manually removed & cleaned to remove the suspended solids. Also there is a possibility of damage that can be caused to the filter elements due to occasional abnormal working conditions wherein large size particles enter the Strainer with a higher impact load. The new operating system takes into account all these aspects as stated above and the design of the new filter/ Strainer fulfil all the conditions stated above including conditions under adverse working.

[0004] In most of the prior art, the assembly has to be opened to clean the Strainer, therefore it is not 100% leak proof. As a result by pass of the solids always takes place along with the filtrate, therefore the design of the strainer is not 100% leak proof. In most of the existing prior art filter/Strainer the filter element either uses wire mesh or perforated filter element which under abnormal working conditions due to the high impact load damage to the element without the knowledge of the end users.

[0005] In all the existing prior art Strainers, the filtration process has to be stopped during manual cleaning operation for hours, since manual cleaning involves the following steps Stop the flow, open the filter unit and taking out the element, cleaning of the element and refitting the same. In large size strainer large number of manpower is required during manual cleaning process. [0006] Most elements in strainers are flexible and unstable since the element comprises wire mesh elements with woven construction. Due the weak construction of the filter element, the element gets damaged under high pressure operating conditions, thereby requiring frequent replacement of the same.

[0007] Accordingly, the objects of this invention include provision of:

a) A strainer assembly which has a 100% leak proof design, thereby preventing by pass of solids.

b) A strainer assembly comprising of rigid RIPBAC element wherein the wires are welded together to give the required reliable slot opening and the desired filtrate quality is achieved even under high pressure working condition.

c) A strainer assembly where the flow of the liquid is out to in and the RIPBAC element need not be manually removed for cleaning.

d) A strainer assembly which can be backwashed with lower downtime and without the requirement of manual removal of the element from the filtration assembly. One operator is sufficient for the maintenance of the strainer under normal working conditions.

PRIOR ART

[0008] CA1211721 (Al) titled "Basket Strainer" provides for a strainer for filtering liquids which includes a housing having an inlet port and an outlet port. A removable filtering element is located within the housing and is at the upper end of an upturned section of a port.

[0009] CN 201510790 U titled "Inclined screen-type filter" provides for an inclined screen-type filter comprises a filter box body and a filter screen mounted in the box body, wherein a water inlet and a water outlet are formed on the box body; an overflowing cavity is arranged in the box body; the water inlet is positioned at the top of the overflowing cavity; an overflowing opening lower than the water inlet is formed at the upper part of the overflowing cavity; the filter screen is obliquely coupled below the overflowing opening; a purified water cavity used for accommodating filtered purified water is formed among the filter screen, the overflowing cavity and the box body; and the water outlet is positioned on the side wall of the purified water cavity. The design of the utility model is ingenious, the filter screen is obliquely arranged, when water flows through the surface of the filter screen, most water enters the purified water cavity through the filter screen, and impurities filtered out by the filter screen and a very small amount of water flow into an impurity holding tank under the filter screen along the surface of the filter screen. By adopting the structural design, impurities isolated on the fi lter screen can be washed into the impurity holding tank timely, so as to prevent the impurities from accumulating on the filter screen and blocking the filter screen.

SUMMARY OF THE INVENTION

[00010] The present invention aims at providing a Strainer which is easy to install and requires less maintenance and lower downtime. The invention also aims at providing back wash facility with minimum downtime to remove the suspended solids without opening the Strainer for cleaning. The unique design of the RIPBAC screen enables efficient back wash based on surface filtration principle with a flow from out to in direction. This completely eliminates the need to remove the filter element from the filtration assembly for cleaning.

[0001 1] The invention aims at providing a rigid construction to the RIPBAC screen wherein the wires are welded together to give the required reliable- slot opening which is also suitable for operation under extreme operating conditions.

[00012] The provision for installing the RIPBAC screen inside the Strainer during installation & replacement period takes care of the cleaning & maintenance of the Strainer during abnormal working conditions wherein large size particles enter the filter. Since the RIPBAC screen need not be regularly opened to clean and the flow is from out to in, the element rests inside the filter body to give the leak proof design as against the existing Strainer where the bypass of the solid particles into the filtrate is always a possibility.

BRIEF DESCRIPTION OF THE DRAWING

[00013] Figure 1 illustrates the design of the Strainer assembly suitable for inlet and outlet size lines ranging from 80 NB (3") to 300 NB (12") under the category of small Strainers

[00014] Figure 2 illustrates the design of the strainer assembly suitable for inlet and outlet size lines ranging from 300 NB (12") to 1600 NB (64") under the category of medium & large Strainers

DETAILED DESCRIPTION OF THE DRAWINGS

[00015] Figure 1 illustrates the design of the Strainer assembly suitable for inlet and outlet size lines ranging from 80 NB (3") to 300 NB (12") which provides for an inlet feed pipe (01) which consists of standard flange and the pipe to carry in feed water. The inlet pipe is connected to the body (6) at one end. The other end of the body is connected to the filtrate outlet pipe (02) which consists of standard flange and the pipe to carry the filtrate water. A reducer (03 A) is fitted to the bottom portion of the main body very close to the inlet side of the filter element wherein all the solids are collected on the floor of the main body which automatically goes through the reducer. The slurry drain nozzle (03B) attached to the reducer discharges the unfiltered solid in slurry form during back wash. The main body also comprises of the T joint blind flange (04) suitable for mounting the filter element which can also be opened to clean large size particles collected during abnormal working conditions. The filter element plate screen (05) is positioned inside the T shaped body at slanting angle of approximately 45°. The screen is supported with guide channels (14) which help in maintaining the slope as well prevent mixing of the in feed and the filtrate. The guide channel (14) & T shaped body are connected by closer plate (13) inside on all the three sides (both the sides & bottom) & are welded so that they are rigid in construction & prevent bypassing of the liquid from inlet side to filtrate side. The T shaped body (06) are connected to two dish ends, the left shell closer dish (07) closes the in feed pipe on one side of the T shaped body and the right shell closer dish (08) closes the filtrate outlet pipe on other side of the T shaped body. The 3^rd side of the T shaped body is fitted with shell flange (11) which is bolted to the blind flange (04) which enables the opening and closing of the blind flange with ease, Both the inlet feed pipe and the outlet filtrate pipe are mounted with a pressure sensor (09, 10). The RIPBAC screen consists of closer plate (13) inside the T body to prevent mixing of inlet feed and the filtrate liquid. The blind flange (04) welded / bolted to the screen (05) is securely bolted to the shell body flange (11) by means of bolts & nuts (15). The air/liquid for backwash is introduced through the nozzle (12) provided on the blind flange (04).

Figure 2 illustrates the design of the strainer assembly suitable for inlet and outlet size lines ranging from 300 NB (12") to 1600 NB (64") inlet and outlet lines which provides for an inlet feed pipe (01) which consist of standard flange and the pipe to carry in feed water. The inlet pipe is connected to the body (6) at one end. The other end of the body is connected to the filtrate outlet pipe (02) which consists of standard flange and the pipe to carry the filtrate water. A reducer (03A) is fitted to the bottom portion of the main body very close to the inlet side of the filter element wherein all the solids are collected on the floor of the main body which automatically goes through the reducer. The slurry drain nozzle (03B) attached to the reducer discharge the unfiltered solid in slurry form during back wash. The main body also comprises of the manhole nozzle (04) suitable for installation and maintenance of the filter element. The body also comprises of rigid RIPBAC screen (05) made up of stainless steel construction which is mounted to the body with the help of mounting flange ( 1 1 ) and bolts and nut ( 13). The body comprises of two dish ends, the left shell closer dish (07) closes the inlet feed pipe and the right shell closer dish (08) closes the filtrate outlet pipe. Both the inlet feed pipe and the outlet filtrate pipe are mounted with a pressure sensor (09, 10). The air/liquid for backwash is introduced through the nozzle (12) provided on the main body of the filtrate side.

DETAILED DESCRIPTION OF THE INVENTION:

[00017] The present invention aims at manufacturing a Strainer assembly suitable for inlet and outlet size lines ranging from 3" to 64" inlet & outlet lines sizes through two type of filter designs. Type 1 Strainer is suitable for size ranging from 3" to 12" whereas type 2 Strainer is suitable for size ranging from 12" & above. Operating details & functions are same in both the types of Strainers whereas they are different only for assembly of the element, installation & occasional manual opening, cleaning operation for maintenance & replacement.

[00018] The RIPBAC Strainer assembly comprises of the filter element plate screen (05) which is positioned inside the T shaped body at a slanting angle of approximately 45°. The slanting angle is maintained and the movement of the element is prevented by the guide channel (14) which is placed inside the T shaped body. The guide channel (14) & T shaped body (06) are connected by closer plate (13) inside on all the three sides (both the side & bottom) & are welded to provide rigidity & prevent bypassing of the liquid from inlet side to filtrate side. The T shaped body (06) are connected to two dish ends no. 7& 8 on both the sides. The 3^rd side of the T shaped body is fitted with shell flange (11) which is bolted to the blind flange (04) which enables the opening and closing of the blind flange with ease. The top side of the filter element is welded /bolted to the blind flange (04) at a slanting angle so that when the blind flange (04) is opened the filter element comes out of the T shaped body sliding on the guide channels. The inlet nozzle (01) and filtrate outlet nozzle (02) are welded on both the sides of T shaped body on the straight line so that the Strainer is suitable for on line mounting. In the assembled condition of the Strainer the unfiltered fluid does not come over to the other side of the Strainer due to the closer plate (13) which are located on three sides of the screen and the fourth side of the screen is welded / bolted to the blind flange (04). Similarly in the case of the plate screen needing to be replaced or inspection to be done inside the chamber of the T outer body, it is possible to pull out the plate screen along with the bl ind flange (04) separately from the outer body. The blind flange (04) welded / bolted to the screen (05) is securely bolted to the shell body flange (1 1 ) by means of bolts & nuts ( 15).

[00019] The strainer element is a flat screen wherein triangular wires placed parallely made of stainless steel or other strong, corrosion and rust-resistant material, arranged such that one side of the triangular wires constituting the flat plate substantially faces the inlet nozzle. The two other sides of each triangular wire form a slit which widens radially inwardly between adjacent triangular wires, and with the inward apex of the said triangular^' wires being welded to the projecting portion of each support rod to the triangular wires, at each crossing point. A plurality of support rods runs perpendicular to the triangular wires, at some distance from each other. Width of the gap between adjacent edges of the outward-facing sides of each triangular wire is maintained at no more than a given smallest size of particle which the strainer is designed to strain out.

[00020] RIPBAC back washable Strainer housing can be manufactured in Stainless Steel, Carbon

Steel with epoxy quoting & GRE material based on the requirement.

Working

[00021 ] The new RIPBAC Strainer assembly uses the surface filtration principle in which the flow is always from out to in. Due to the construction of the RIPBAC screen as per the surface filtration principle the unwanted filtration particles are held only to the surface only. During backwash due to venturi effect the particles are discharged easily from the filtration surface. The filter element is positioned almost at 45° angle to the inlet flow of the fluid thereby providing a tangential flow to the incoming liquid. Also since the profile wire slots are placed in the longitudinal direction of the flow the suspended particles which gets stuck on the surface of the filter element slide down to the bottom of the element along with the flow during filtration process as a result the clogging of the filter element is avoided to a large extent.

[00022] As a natural consequence of this arrangement of the housing of the RIPBAC screen, the liquid to be strained enters the inlet chamber and hits the screen almost at tangential trajectory. Based on the element slot opening solid particles larger than the slot opening do not pass through the screen and instead, slide slowly downward, because of the slope, and fall to the bottom of the inlet chamber, near the Slurry Drain reducer (3A). Some lighter solid particles, however, may stick to the plate screen itself, thus reducing the area available for straining during the straining process. There are two pressure sensors (09.

10) located just before the inlet nozzle and after the outlet nozzle that continuously monitor the pressure of the fluid. If sufficient particles remain stuck to the plate screen, it causes a difference in the pressure sensed by the pressure sensor placed near the inlet (9) and the pressure sensed by the pressure sensor placed near the outlet (10). When this pressure differential reaches a pre-determined level, it indicates that the strainer needs to be backwashed.

[00023] A brief backwash cycle pushes the caked solid particles downwards and towards the drain nozzle at the bottom. This backwash is done by

(a) Closing the inlet feed pipe ( 1 );

(b) Closing the filtrate outlet pipe (2);

(c) Introducing the inlet liquid flow from the main inlet pipe to the back wash pipe (12) positioned on the blind flange ; and

(d) Opening the Slurry Drain Nozzle (3B) in that order, in quick succession for an interval of 5 to 10 seconds.

[00024] The inlet feed water introduced by Step (c) pushes the filtrate that is still in the outlet chamber to go back the way it came, i.e. into the inlet chamber, inwards and downwards, till it exits the strainer through the Drain Nozzle (3B). In the process of flowing downwards and inwards into the inlet chamber, the filtrate displaces the particles caked on the outside of the plate screen (5) due to surface filtration principle.

[00025] Then, the steps (d) to (a) above are reversed, in that order, to start the straining cycle once again. )

[00026] Although embodiments of this invention have been shown and described, it is to be understood that various modifications and substitutions, as well as rearrangements of parts and components can be made by those skilled in the art without departing from the novel spirit and scope of the invention.

Claims

A Strainer assembly for industrial filters, suitable for inlet and outlet size lines ranging from 3" & above, comprising a removable filter element plate screen which is a bolted construction, the said filtrate element being fixed at an angle of approximately 45° to the base of the body; the slanting angle being maintained by means of an element mounting flange or guide channel; the element mounting flange/guide channel and the filtrate element being connected by means of a closure plate; the said closure plate seals the filtrate from mixing with the inlet fluid; the said filtrate element separating the main & body at two dish ends which are welded to the main body; the inlet nozzle and outlet nozzle are welded to diametrically opposing sides of the body; the said filtrate element being cleaned by backwash facility through the backwash nozzle which triggers into play once ΔΡ levels are reached; the said backwash cycle occurring by closure of both the inlet and outlet valves; the filtrate being channelled into the backwash nozzle and falling upon the angularly placed filtrate element resulting in the particles on the filtrate element being pushed to the floor of the body on the inlet side; the resultant slurry being drained through a reducer and expelled from the main body through a slurry drain nozzle; the said process being reversed once the filtrate element is cleaned; the said body further comprising either a T arm or a manhole for facilitating removal of the filtrate element and physical removable of the particles; the said strainer assembly having lower downtime, being more efficient.

A strainer assembly as claimed in Claim 1 suitable for inlet and outlet sizes ranging from 12" and upwards; comprising of a manhole positioned on the body and of diameter slightly larger than the width of the filtrate element, to enable the filtrate element to be slid inside the body and bolted.

A strainer assembly as claimed in Claim 2, wherein the larger particles can be removed physically by opening the manhole and physically removing such material that is bigger than the drain hole nozzle in size.

A strainer assembly as claimed in Claim 2, wherein the filtrate element is fixed by means of element mounting flange; the said element mounting restricting the movement of the filtrate element.

A strainer assembly as claimed in Claim 1 suitable for inlet and outlet sizes ranging from 3" to 12" comprising an filtrate element positioned inside the T shaped body at an angle; the said slanting angle being maintained by means of a guide channel; the guide channel & T shaped body are connected by closer plate inside on all the three sides (both the side & bottom), welded to provide rigidity & prevent bypassing of the liquid from inlet side to filtrate side; the T shaped body are connected to two dish ends no. on. both the sides; the 3^rtl side of the T shaped body is fitted with shell flange which is bolted to the blind flange which enables the opening and closing of the blind flange with ease; the top side of the fi lter element is welded /bolted to the blind flange at a slanting angle in such a manner that when the blind flange is opened the filter element comes out of the T shaped body sliding on the guide channels.

6. A strainer assembly as claimed in Claim 4 wherein the blind flange is welded / bolted to the body flange by means of bolts & nuts.

7. Ά Strainer assembly as claimed in Claim 4 wherein the blind flange is connected to the T arm by means of bolts and nuts.

8. A strainer assembly system as claimed in any on the preceding claims as substantially described herein with reference to the drawings.