Clogging of pipes due to encrustation and scale formation reduces the flow and hence it is necessary either to remove the encrustation or to replace the pipe, in order to restore the carrying capacity of the pipe line.
1)Water Supply Pipes
1f the pipe is clogged badly the best solution will be to replace it with new one. However, if clogging is partial then it can be removed by passing a wire brush attached to a small metal rod. By pushing the rod back and forth in the section of the pipe to be cleaned all particles a(l1ierin~ to the pipe can he removed. Another method is to clean the pipe using dilute nitric acid lo dissolve all the scales..Yet another method used for cleaning pipe lines is by flushing with water flowing at high velocity. While tlushing, care is to be taken to ensure that the flows are in one direction and the dirty water does not entcr the cleaned sections. Also care shall be taken to ensure that the water pressure does not exceed the permissible limits. If the pressure is more the pipe lines are likely to burst under high pressure. It is advantageous if the water used for flushing is mixed with chlorine solution of strength 10 mg/L which helps in dislodging microscopic biological growths, and disconnecting the pipe line from the segment which is not clogged.
2)Sewer Lines
The objective of sewer maintenance is to keep the systeril operating satisfactorily without breakdown. The system is susceptible for corrosion, erosion, clogging and other deterioration. One of the critical problems facing the sewer lines maintenance is that of clogging. Clogging can be in horizontal lines or vertical stacks. We will study the removal of clogging in horizontal lengths as well as in vertical stacks. a) Removal of Clogging in Horizontal Lengths
i)Portable Pump Set
In case where sewers are blocked completely and sewage has accumulated in manholes, the collected sewage has to be pumped out to tackle the sewer blockage. Such pumps should be of non-clogging type, preferably on four wheel trailors for the larger size and should be provided with a self-priming unit to save time and effort. Small pneumatic pumps c ~ m be Repairing Materials for DBfects in S'anitary FittingrKcp:tiring h4aicri:ds used where high lifts are required and the volume of Ilquid to be pumped is no1 li~rgc. such as when pumping oul flooded basei~ients and dewatering deep trench excavalions.
ii)Sectional Sewer Rods
These rods are used for cleaning small sewers. The sewer rods may be of brunhoo or teakwood or light metal usually about one meter long at the end of which is a couplmg which remains intact in tile sewer but can be easily disjointed in the manhole. Sections of the rods are pushed down the sewer until the obstruction is reached and dislotlged. The tront or the advancing end of the sewer rod is generally fitted with a cutting edge to cut and dislodge Ule obsvuciions. Tliese rods are also useful to locate the obstruction from either manhole in case that particular portion of the sewer has to be exposed for repairing the damages.
iii)Flexible Sewer Rod
The flexible rod used in manuill cleaning is usually made by sandwiching a m~uiila rope between bnmboo strips and trying at short intervals. The flexible rod is introduced first from one mallhole to the other, its end being connected to a thicker rope which, when dragged down thc sewer. tlraws out sand and detritus into the downstream manhole. This method is adopted in routine clearling of sewers.
iv)Ferret Used in Conjunction with a Fire Hose
This is used for breaking and removing and stoppages. I1 uses a fire hose connection 'and produces a small but high velocity stream of water forward (upstream) from a central nozzle and several lower velocity jets to the rear (downstream). The forward strean] loosens the accumulated debris ahead of the tool and the rear jets of the ferrets admit waler to wash Ihe sand back downstream where it can be removed from Ihe manhole manually. The ferret must be attached to a fire hose oC sufficient length to reach at least the nexl manhole and must he kept in motion to prevent sand from locking fire hose in the line.
v)Sewer Cleaning Bucket Machine
The bucket machine co~lsists of two powered winches with cables in between. In cleanlng a second of sewer, the winches ire ccntred over two adjacent mLulholes. To gel the cable fro111 (11163 wiiicli Lo tlle olher, it is necessary lo thread the cable through the sewer line by means of sewer rod?. The cable fronl the drurn of each winch is fastened to the barrel on each end-of an expansion sewer bucket fitted with closing device, so that the bucket can be pulled in either direction by the machine on the appropriate end.The bucket is pulled into the loosened material in the sewer until the operator feels that il is loaded with debris. The;motor is then tl~ron out of gear and the opposing winch is put iillo action. When the reverse pull is started, the bucket automatically closes and the dirt is deposited in a truck or a trailer. This operation is repeated until the line is clear. Various buckel sizes are available for sewers of 150 to 900 mm in size. The machine is also used along with other scrapping irlstrui~ients for loosening sludge banks or detritus or cutting roots and dislodging obstructions.
vi)Dredger
A dredger can be used Lo clean larger manlloles. It consists of a crane and a pulley wlth the help of which a grab bucket is lowered. This scrapes the bottom deposits and brings it to lllu ground whcre the buckel opens and the silt is automatically dropped into a truck or a trailer The disadvantage in this system is that it can not clean the comers of the catchpits of m,mholes. Sometimes Lhe deposits at the corners may become so hard that the same may bc required to be chiselled out.
vii) Kodding Machine with Flexible Sewer Rods
This consists of a machine which rotates a flexible rod to which is attached the cleani~ig tool such as auger, corkscrew or hedgehog and sand cups. The flexible rod consists of a series of steel rods with screw couplings. The flexible rod is guided through the manhole by;I bent pipe. The machine rotates the rod with the tool attached to one end, the other being fixed to the machine.The rotating rod is thrust into the bent holding the rod near the couplings. As the rod is thrust inside. the machine also is drawn towards the manhole. The rod is pulled in and out in quick succession when the tool is engaging the obstruction, so as to dislodge or loosen it.When the obstmction is cleared, the rod is pulled out by meals of clamps keeping the rod rotating to facilitate quick and easy removal.
viii) Scrapper
This method is used for sewers of dia larger than 750 mm. The scrapper is an assembly of ivootlen planks of slightly smaller size than the sewer to be cleaned. Where the scrappers can not be lowered through the opening of a manhole, the scrapper has to be assembledinside the manhole. The scrapper chains, being attached to a control chain in the manhole where it is lowered, is then connected to a winch on the next downstreain manhole by means of chains. The winch is then revolved to push the debris ahead of the scrapper. The heading up of the tlow behind the scrapper will also assist in pushing it in the forward direction. This ensures that the bottom and the sides of the sewer are cle,med thoroughly. The scrapped debris is removed manually.
ix)Automatic Flushing Tanks
The automatic flushing tanks employ a11 outside water source with a controlled flow so that the required quantity of water is released at predetermined intervals.
x)Hydraulically Propelled Devices
The hydraulically popelled devices take adv,mtage of the force of impounded water to effectively clear sewers. Efficiency depends on the hydraulic principle that an increase in velocity in a moving stream is accompanied by a greatly increased ability to move entrained material. T l ~ e transporting capacity of water varies as the sixth power of its velocity.
xi)Flush Rags
A most effective tool for cleaning portions of sewers where rods cannot be used is the sewer tlusher or flush bag. The flusher is a canvas bag or rubber bag equipped with a fire hose coupler at one end reducer at the other end. The flusher is connected to the firehose and placed in the downstrean1 end from the point where a choke is located. The bag is allowed to fill up until it expands and seals the sewer. The upstream pressure built up due to this damning effect breaks loose the obstructions. Caution must bc exercised in using these types of devices as there is a likelihood of sewage tlowing back into the hose connections or breaking of the pipes or joirmts due to high pressures that may develop.
xii) Sewer Balls
These are simple elastic pneumatic type rubber balls which can be blown up to varying degrees of inflation. They are manufactured in sizes from 150 to 750 mrn dia when fully inflated. When used in cleaning a sewer, the ball is first inflated and then wrapped in a canvas cloth, the edges of which are sewed together. A trial line, little longer than the distance between the manholes, is attached securely to the covering . The size of the ball and the covering shall be such as to fit fairly snugly into the sewer. Immediately the ball is thrust into the sewer. sewage commences to back up in the manhole and continues to rise unt~l such time as its pressure is great enough to force sewage under the ball and movirig it dowristream through the pipe.
xiii) Sewer Scooter
This arrangement is an improved version of the scrapper and consists of the two jacks. a controlling rope and the scooter with a tight fitting shield. In contrast to the scrapper, the scooter conipletely stops any flow of sewage. The scooter, attached to the control rope, is lowered into the manhole and then into the sownstream sewer line. The downstream manhole jack is lowered into place from the road and the upper manhole jack set across the top of the manhole.When the scooter is introduced into the line. it stops the flow of sewage thus building up a head behind the shield. The resulting pressure causes the scooter to move through Ule seweu' until it accumulates enough debris to stop its movement. The head is then allowed to build up approximately l m before the control rope is pulled, causing the shield to fold back, thus allowing the accumulated sewage to gush into the sewer downstream, flushing the debris ahead to the next manhole from where it is removed. The control rope is released, clearing Ule shield against the sewage and causing the scooter to advance again until the debris stops its movement. This process is repeated till the scooter reaches the downstream manhole where it may be removed or allowed to continue through the next section.
b) Removal of Clogging in Vertical Stacks
However, if the stoppage I blockage is in the vertical part of the sewer line, often called the soil stack, you may have to cut a hole in the cast iron pipe and insert the spring steel auger whicli is also called a snake through that, Choose a convenient spot to work on, perhaps about three feet up from the cellar floor. Keep the hole small. A substitute to 'Snake' is hcavy rubber garden hose. The hose can be used if the 'snake' is not readily available with the plumber. You want it merely large enough so you can insert a snake and small enough
Diamond-point Chisel Method : If you use a diamond-point chisel and hanuner, be careful to keep the hole small 'at first and enlarge it slowly and carefully so as to not split the pipe.When the hole is not just an inch in diameter, try inserting the snake. If the hole is too small to work through (of course it has to be a little larger than the end of the snake), enlarge it a little more. Push the snake in the direction of the stoppage and break it up or push it along.When your stoppage is cleared, you can turn to the task of making the hole round and cutting a thread for a pipe plug. Use a pipe tap reamer to enlarge the hole and make it perfectly round. A square wrench or monkey wrench can be used to turn the reamer. Then insert the pipe tap, making sure it is perpendicular to the surface of the centre of your hole,and turn the tap slowly with a monkey wrench in a clockwise k e c t i o n to form a regular or righthand thread. When the tap stops or becomes too hard to turn without brute strength,turn it back and oil the surface you are cutting. Turn the tap in again and repeat the lnanoeuver of oiling and cutting until you have a thread all the way into the pipe. Try screwing a pipe plug in. If it seems to fit reasonably tightly, remove it and apply white lead or pipe compound (or "dope" ) to the pipe threads and then screw the plug in.
Metal Hole-saw Method : The other method of cutting a hole in cast iron pipe is to use a metal hole-saw or cutter. It has a square shank so thaS it can be fitted into a bit brace. It can also be fitted into angkxtric drill. Note that you have a centre ibt the circular saw blade.Different sized saw blades or cutters can be inserted and screwed tight into various slots to cut holes for pipe taps of 25 mm, 32mm, 40mm and 50mm diameters. Be careful not to press too hard or you may break the cutter. If you are using an electric drill, a pilot drill of 12mm diameter is advised. Holes cut with a metal hole saw are perfect circles and do notn have to be reamed. Use a pipe tap to cut a thread in the same manner as just described for the Diamond-point Chisel Method. Then dope and screw in the pipe plug. Rodding method:Cleaning by rods is also possible in vertical soil stacks.
1)Water Supply Pipes
1f the pipe is clogged badly the best solution will be to replace it with new one. However, if clogging is partial then it can be removed by passing a wire brush attached to a small metal rod. By pushing the rod back and forth in the section of the pipe to be cleaned all particles a(l1ierin~ to the pipe can he removed. Another method is to clean the pipe using dilute nitric acid lo dissolve all the scales..Yet another method used for cleaning pipe lines is by flushing with water flowing at high velocity. While tlushing, care is to be taken to ensure that the flows are in one direction and the dirty water does not entcr the cleaned sections. Also care shall be taken to ensure that the water pressure does not exceed the permissible limits. If the pressure is more the pipe lines are likely to burst under high pressure. It is advantageous if the water used for flushing is mixed with chlorine solution of strength 10 mg/L which helps in dislodging microscopic biological growths, and disconnecting the pipe line from the segment which is not clogged.
2)Sewer Lines
The objective of sewer maintenance is to keep the systeril operating satisfactorily without breakdown. The system is susceptible for corrosion, erosion, clogging and other deterioration. One of the critical problems facing the sewer lines maintenance is that of clogging. Clogging can be in horizontal lines or vertical stacks. We will study the removal of clogging in horizontal lengths as well as in vertical stacks. a) Removal of Clogging in Horizontal Lengths
i)Portable Pump Set
In case where sewers are blocked completely and sewage has accumulated in manholes, the collected sewage has to be pumped out to tackle the sewer blockage. Such pumps should be of non-clogging type, preferably on four wheel trailors for the larger size and should be provided with a self-priming unit to save time and effort. Small pneumatic pumps c ~ m be Repairing Materials for DBfects in S'anitary FittingrKcp:tiring h4aicri:ds used where high lifts are required and the volume of Ilquid to be pumped is no1 li~rgc. such as when pumping oul flooded basei~ients and dewatering deep trench excavalions.
ii)Sectional Sewer Rods
These rods are used for cleaning small sewers. The sewer rods may be of brunhoo or teakwood or light metal usually about one meter long at the end of which is a couplmg which remains intact in tile sewer but can be easily disjointed in the manhole. Sections of the rods are pushed down the sewer until the obstruction is reached and dislotlged. The tront or the advancing end of the sewer rod is generally fitted with a cutting edge to cut and dislodge Ule obsvuciions. Tliese rods are also useful to locate the obstruction from either manhole in case that particular portion of the sewer has to be exposed for repairing the damages.
iii)Flexible Sewer Rod
The flexible rod used in manuill cleaning is usually made by sandwiching a m~uiila rope between bnmboo strips and trying at short intervals. The flexible rod is introduced first from one mallhole to the other, its end being connected to a thicker rope which, when dragged down thc sewer. tlraws out sand and detritus into the downstream manhole. This method is adopted in routine clearling of sewers.
iv)Ferret Used in Conjunction with a Fire Hose
This is used for breaking and removing and stoppages. I1 uses a fire hose connection 'and produces a small but high velocity stream of water forward (upstream) from a central nozzle and several lower velocity jets to the rear (downstream). The forward strean] loosens the accumulated debris ahead of the tool and the rear jets of the ferrets admit waler to wash Ihe sand back downstream where it can be removed from Ihe manhole manually. The ferret must be attached to a fire hose oC sufficient length to reach at least the nexl manhole and must he kept in motion to prevent sand from locking fire hose in the line.
v)Sewer Cleaning Bucket Machine
The bucket machine co~lsists of two powered winches with cables in between. In cleanlng a second of sewer, the winches ire ccntred over two adjacent mLulholes. To gel the cable fro111 (11163 wiiicli Lo tlle olher, it is necessary lo thread the cable through the sewer line by means of sewer rod?. The cable fronl the drurn of each winch is fastened to the barrel on each end-of an expansion sewer bucket fitted with closing device, so that the bucket can be pulled in either direction by the machine on the appropriate end.The bucket is pulled into the loosened material in the sewer until the operator feels that il is loaded with debris. The;motor is then tl~ron out of gear and the opposing winch is put iillo action. When the reverse pull is started, the bucket automatically closes and the dirt is deposited in a truck or a trailer. This operation is repeated until the line is clear. Various buckel sizes are available for sewers of 150 to 900 mm in size. The machine is also used along with other scrapping irlstrui~ients for loosening sludge banks or detritus or cutting roots and dislodging obstructions.
vi)Dredger
A dredger can be used Lo clean larger manlloles. It consists of a crane and a pulley wlth the help of which a grab bucket is lowered. This scrapes the bottom deposits and brings it to lllu ground whcre the buckel opens and the silt is automatically dropped into a truck or a trailer The disadvantage in this system is that it can not clean the comers of the catchpits of m,mholes. Sometimes Lhe deposits at the corners may become so hard that the same may bc required to be chiselled out.
vii) Kodding Machine with Flexible Sewer Rods
This consists of a machine which rotates a flexible rod to which is attached the cleani~ig tool such as auger, corkscrew or hedgehog and sand cups. The flexible rod consists of a series of steel rods with screw couplings. The flexible rod is guided through the manhole by;I bent pipe. The machine rotates the rod with the tool attached to one end, the other being fixed to the machine.The rotating rod is thrust into the bent holding the rod near the couplings. As the rod is thrust inside. the machine also is drawn towards the manhole. The rod is pulled in and out in quick succession when the tool is engaging the obstruction, so as to dislodge or loosen it.When the obstmction is cleared, the rod is pulled out by meals of clamps keeping the rod rotating to facilitate quick and easy removal.
viii) Scrapper
This method is used for sewers of dia larger than 750 mm. The scrapper is an assembly of ivootlen planks of slightly smaller size than the sewer to be cleaned. Where the scrappers can not be lowered through the opening of a manhole, the scrapper has to be assembledinside the manhole. The scrapper chains, being attached to a control chain in the manhole where it is lowered, is then connected to a winch on the next downstreain manhole by means of chains. The winch is then revolved to push the debris ahead of the scrapper. The heading up of the tlow behind the scrapper will also assist in pushing it in the forward direction. This ensures that the bottom and the sides of the sewer are cle,med thoroughly. The scrapped debris is removed manually.
ix)Automatic Flushing Tanks
The automatic flushing tanks employ a11 outside water source with a controlled flow so that the required quantity of water is released at predetermined intervals.
x)Hydraulically Propelled Devices
The hydraulically popelled devices take adv,mtage of the force of impounded water to effectively clear sewers. Efficiency depends on the hydraulic principle that an increase in velocity in a moving stream is accompanied by a greatly increased ability to move entrained material. T l ~ e transporting capacity of water varies as the sixth power of its velocity.
xi)Flush Rags
A most effective tool for cleaning portions of sewers where rods cannot be used is the sewer tlusher or flush bag. The flusher is a canvas bag or rubber bag equipped with a fire hose coupler at one end reducer at the other end. The flusher is connected to the firehose and placed in the downstrean1 end from the point where a choke is located. The bag is allowed to fill up until it expands and seals the sewer. The upstream pressure built up due to this damning effect breaks loose the obstructions. Caution must bc exercised in using these types of devices as there is a likelihood of sewage tlowing back into the hose connections or breaking of the pipes or joirmts due to high pressures that may develop.
xii) Sewer Balls
These are simple elastic pneumatic type rubber balls which can be blown up to varying degrees of inflation. They are manufactured in sizes from 150 to 750 mrn dia when fully inflated. When used in cleaning a sewer, the ball is first inflated and then wrapped in a canvas cloth, the edges of which are sewed together. A trial line, little longer than the distance between the manholes, is attached securely to the covering . The size of the ball and the covering shall be such as to fit fairly snugly into the sewer. Immediately the ball is thrust into the sewer. sewage commences to back up in the manhole and continues to rise unt~l such time as its pressure is great enough to force sewage under the ball and movirig it dowristream through the pipe.
xiii) Sewer Scooter
This arrangement is an improved version of the scrapper and consists of the two jacks. a controlling rope and the scooter with a tight fitting shield. In contrast to the scrapper, the scooter conipletely stops any flow of sewage. The scooter, attached to the control rope, is lowered into the manhole and then into the sownstream sewer line. The downstream manhole jack is lowered into place from the road and the upper manhole jack set across the top of the manhole.When the scooter is introduced into the line. it stops the flow of sewage thus building up a head behind the shield. The resulting pressure causes the scooter to move through Ule seweu' until it accumulates enough debris to stop its movement. The head is then allowed to build up approximately l m before the control rope is pulled, causing the shield to fold back, thus allowing the accumulated sewage to gush into the sewer downstream, flushing the debris ahead to the next manhole from where it is removed. The control rope is released, clearing Ule shield against the sewage and causing the scooter to advance again until the debris stops its movement. This process is repeated till the scooter reaches the downstream manhole where it may be removed or allowed to continue through the next section.
b) Removal of Clogging in Vertical Stacks
However, if the stoppage I blockage is in the vertical part of the sewer line, often called the soil stack, you may have to cut a hole in the cast iron pipe and insert the spring steel auger whicli is also called a snake through that, Choose a convenient spot to work on, perhaps about three feet up from the cellar floor. Keep the hole small. A substitute to 'Snake' is hcavy rubber garden hose. The hose can be used if the 'snake' is not readily available with the plumber. You want it merely large enough so you can insert a snake and small enough
Diamond-point Chisel Method : If you use a diamond-point chisel and hanuner, be careful to keep the hole small 'at first and enlarge it slowly and carefully so as to not split the pipe.When the hole is not just an inch in diameter, try inserting the snake. If the hole is too small to work through (of course it has to be a little larger than the end of the snake), enlarge it a little more. Push the snake in the direction of the stoppage and break it up or push it along.When your stoppage is cleared, you can turn to the task of making the hole round and cutting a thread for a pipe plug. Use a pipe tap reamer to enlarge the hole and make it perfectly round. A square wrench or monkey wrench can be used to turn the reamer. Then insert the pipe tap, making sure it is perpendicular to the surface of the centre of your hole,and turn the tap slowly with a monkey wrench in a clockwise k e c t i o n to form a regular or righthand thread. When the tap stops or becomes too hard to turn without brute strength,turn it back and oil the surface you are cutting. Turn the tap in again and repeat the lnanoeuver of oiling and cutting until you have a thread all the way into the pipe. Try screwing a pipe plug in. If it seems to fit reasonably tightly, remove it and apply white lead or pipe compound (or "dope" ) to the pipe threads and then screw the plug in.
Metal Hole-saw Method : The other method of cutting a hole in cast iron pipe is to use a metal hole-saw or cutter. It has a square shank so thaS it can be fitted into a bit brace. It can also be fitted into angkxtric drill. Note that you have a centre ibt the circular saw blade.Different sized saw blades or cutters can be inserted and screwed tight into various slots to cut holes for pipe taps of 25 mm, 32mm, 40mm and 50mm diameters. Be careful not to press too hard or you may break the cutter. If you are using an electric drill, a pilot drill of 12mm diameter is advised. Holes cut with a metal hole saw are perfect circles and do notn have to be reamed. Use a pipe tap to cut a thread in the same manner as just described for the Diamond-point Chisel Method. Then dope and screw in the pipe plug. Rodding method:Cleaning by rods is also possible in vertical soil stacks.
No comments:
Post a Comment