How to connect cast iron pipes. Connection and installation of cast iron pipes How to connect cast iron pipes to each other

This article will discuss how to connect a cast-iron pipe with a plastic one - preparation for work, dismantling the cast-iron pipe, installing a plastic one, and performing their connection.

Plastic pipes are very popular today. Their low weight and resistance to corrosion allows them to become a full-fledged replacement for cast iron pipes.

In any case, sooner or later it will be necessary to replace the existing old cast-iron pipes with plastic, more modern ones. And it is desirable that this, and not as a result of an accident.

An important step in such a replacement is the connection of cast-iron pipes and plastic pipes, which is usually performed by a qualified specialist.

However, deal with how to connect plastic pipe with cast iron, almost anyone who has an idea about plumbing and knows how to use a grinder can independently.

Preparation for repair work

The first step is to decide which specific area you want to change. In this case, a plastic pipe with a diameter of 50 mm is required, and in the case of a riser, the diameter of the pipe should be 110 mm.

The connection of plastic and cast iron pipes of this type is quite simple and does not require special knowledge and skills.

The connection between them is carried out using a socket at one end of the pipe. A special sealing gum is inserted into the groove of the pipe socket. After connecting the pipes, they are attached to the walls with clamps.

To perform the work, you will need the following materials and tools:

• Plastic pipe of the required diameter;
• Hammer with a nozzle made of wood or rubber;
• Cutting tool in the form of a grinder or a hacksaw;
• A coupling with which the transition from a cast-iron pipe to a plastic one is made.

Dismantling of cast iron pipes

The greatest difficulties in the process of repairing sewers arise in the process of dismantling old pipes from cast iron. The easiest way is to cut these pipes with a grinder, while not forgetting to wear a respirator and goggles to avoid such consequences as a bad runny nose and cough.

The easiest way is to dismantle the cast-iron pipe to the socket, which makes it much easier to work and spend less effort on connecting the cast-iron pipe to the plastic one.

This may require sawing a plastic pipe, for this you can cut it in a circle a little further than the middle, after which the pipe bursts during axial rotation or the application of slight pressure.

Important: transition couplings, sold in a wide range in specialized stores, make it possible to significantly simplify the connection of plastic pipes and cast iron pipes.

Special nuances of work

When performing repair work, in particular, the connection of a plastic pipe with a cast iron one, a number of important nuances should be taken into account:

• Cast iron is a brittle metal, therefore it is not recommended to use a hammer with a metal nozzle- a strong blow can break off a piece of cast iron that gets inside the pipe, clogging it or reducing its clearance in the sewer system, so it is recommended to use a hammer with a rubber or wooden nozzle;
• In the absence of a grinder, you can use a regular hacksaw, which will increase the time to complete the work, but will not particularly affect its quality;
• Plastic pipes should be installed taking into account inspection hatches. Their absence leads to the need to cut pipes in the event of an accident, which entails additional costs.

Connecting plastic and cast iron pipes

The question of how the connection is made can arise not only if it is necessary to connect a cast-iron pipe with a plastic one, but also in case of problems with an existing connection of these pipes.

Let's consider both options in more detail:

1. Leaks in the existing connection of pipes made of plastic and cast iron occur in the event of sudden changes in temperature or water hammer.
   Water hammers happen very rarely, but temperature drops are a fairly common problem, since every shutdown and on hot water, as well as replacing hot water with cold water, create certain difficulties.

The main causes of problems in this case are poor-quality fittings and the difference in the coefficients of thermal expansion of plastic and cast iron.

Hot water causes strong heating of cast iron, causing it to expand unevenly compared to plastic, as a result of which, over time, the fitting cracks or its fastening weakens.

Important: most often this happens with Chinese fittings, but high-quality fittings are also not eternal and wear out over time.

The solution to this problem may be to tighten the self-unwinding fitting or replace the cracked one with a new one. Currently, the assortment also includes fittings with protection against self-unwinding, as well as fitting crimping systems, so in this case it is undesirable to try to save on components.

1. Plastic and cast-iron pipes are most often connected to save money, for example, if there is a cast-iron riser, they make wiring from plastic pipes or try to lengthen the cast-iron pipeline.

In this case, it is still desirable to completely eliminate the problem, for example, by complete replacement riser to plastic, since to the problems that are relevant for the first option (leakage of the joint), another equally important one is added: in the case of unauthorized insertion into a general engineering structure, using a radically different material, the entire material liability for possible accidents falls precisely on the owner of this tie-in.

In the event of an accident, an act will be drawn up, according to which the housing and communal services, the housing office, etc., up to the neighbors themselves, will demand compensation for damage and the costs of eliminating the accident from the person who carried out the tie-in.

How to Practically Bond Metal to Plastic

In the event that, taking into account possible problems, nevertheless, it was decided to connect plastic and cast iron pipes, you can invite specialists for this, or do the work yourself.

1. First of all unscrew the clutch cast iron pipeline at the place of the future connection with a plastic pipe, or cut off old pipe with the help of a grinder.
2. Lubricate with grease or oil and the edge of the pipe to the point where it comes out of the die, and cut the thread with a thread cutter.
3. They wipe the thread, wrap FUM tape or tow on it and lubricate it with silicone.
4. A press fitting is screwed onto the thread.

Important: it is advisable to screw the press fitting by hand, without using a key, otherwise it may crack.

It is better to tighten the press fitting until a possible leak is stopped, after the water is turned on, than to squeeze it immediately with a key.

1. Due to the difference in the thermal expansion coefficients of plastic and metal, PVC fittings with internal thread it is not recommended to wind on metal.
2. When installing hot water or heating systems, it is necessary to use transitional couplings with sealing rubber, or detachable brass couplings with a PVC element.

The practical application of the tips and recommendations of this article allows you to qualitatively and reliably connect cast iron and plastic pipes, having minimal plumbing knowledge and skills, both in the case of repair and in the case of a planned replacement of cast iron pipes with plastic ones.

I just want to repeat once again that it is better to do the work in advance, without waiting for an accident, especially since plastic pipes have more advantages and do not require personal care, and also do not cause unpleasant odors.

During the operation of any pipeline, there will be no problems if all its elements are correctly connected. The market offers tubular products with a socket (SME) and without it (SMU).

For each type of material there are various ways cast iron pipe connections. In addition, pipelines are horizontal and vertical. Depending on these indicators, various elements for attaching the system to surfaces.

Methods for joining pipeline elements made of cast iron

The tightness of the socket connections provides rubber gasket, installed in the socket. For the installation of smooth sections, various cast-iron pipe fittings are used: couplings, bends, elbows, tees, crosses, flanges, plugs, saddles.

There are three types of couplings:

• - cast-iron connecting coupling - a cylinder equipped with an internal thread is used when connecting two pieces of a tubular product with the same diameter;
• - adapter in the form of two cylinders equipped with a thread on inner surface- it is applied to connection of pieces with various diameters;
• - futorka - a cylinder with a thread on the inner and outer surface, used when connecting elements in heating systems.

The ends of the couplings can have flanges or sockets, which allows you to mount the system from various kinds pipe products.

Connection of cast-iron pipes in the places of turns of the pipeline is carried out by including in the system of bends at an angle of 10°, 15°, 30°, 45°, 60o, 90o. There are 2 types of these elements:

• - on both ends of the internal thread;
• - at one end external thread, on the other - internal.

How to connect cast iron pipes at branchings? If it is necessary to join three pipe elements, two types of tees are used with a thread on the inner surface: three cylinders with the same cross section or two cylinders with the same cross section, and the third with smaller dimensions.

The ends of the tees can be equipped with flanges or sockets in different combinations. To connect four segments, there are crosses - two cylinders with sockets or flanges at the ends.

The cast iron plug is made in the form of a cylinder, one end of which looks like a coupling, the other is sealed. There are also plugs in the form of a hexagon, flanged and with ribs.

The fixing flange is made of malleable cast iron, protected from corrosion by an epoxy coating. Tightness is ensured by an elastomer gasket. Mounted by clamping the crimp ring.

The connection of cast-iron pipes in places where a secondary pipeline branches off from the main pipeline is made using a saddle. It is suitable for tubular products with a diameter of 80 to 600 mm. After installing the saddle, valves, flanged valves or a secondary branch are attached to it using two clamps with a movable casing.

The pipeline can be installed in horizontal and vertical position. With a vertical arrangement, it is important to securely strengthen the system. Ductile iron clamps are mounted at equal distances under the sockets. For horizontal wiring, hooks, metal brackets, consoles are used. The distance between the fasteners must be equal.

Joining cast iron with other materials

During repairs, cast iron pipelines are often replaced with plastic ones without changing the riser, or part of the riser is replaced with a piece of plastic, without affecting communications from above and below. In such situations, docking of plastic and cast iron pipes is necessary. The connection of cast iron with plastic can be done in several ways:

• - if a socket is preserved on a cast iron product, then it is necessary to insert a rubber adapter into it, previously lubricated with sealant, and insert a plastic piece;
• - if the end is smooth, the rubber cuff should be put on the cast iron element, and then the plastic adapter should be put on the cuff;
• - most reliable way connect a plastic and cast iron pipe - use a press fitting or an adapter for plastic on one side and with metal thread on the other.

Join process:

• - evenly cut off the end of the old pipeline;
• - smear it with grease and cut the thread;
• - wipe the thread and wrap a sealant around it (for example, FUM tape);
• - screw on the coupling.

The coupling must be wound by hand so that it does not burst. If necessary, it can be tightened after connecting the system (if a leak appears).

The connection of a cast-iron pipe with a steel one is carried out by means of a branch pipe, one end of which is equipped with a socket, the other with an adapter for steel. These elements are different in length and weight.

The end of the old pipeline is inserted into the socket. A thread is cut into the steel end, first the FUM tape is wound onto it, then coupling. A threaded steel pipe element is screwed to the other end of the coupling. On this connection of cast iron and steel pipe completed.

Often problems are created by connecting to the sewer pipeline of the toilet bowl. This procedure is quite simple if the toilet has a vertical outlet (in houses built before 1960). In this case, the toilet is simply placed in the socket.

But everything is so simple only at first sight. With this setup, not really nice smell will be distributed throughout the apartment. Therefore, when docking, it is necessary to use a rubber cuff. It must be put on the outlet of the toilet, only then you can attach it to the sewer.

A more labor-intensive connection of a toilet bowl with a cast-iron pipe in the presence of an oblique outlet, which is found in all residential buildings built after 1960, including in elite cottages. The easiest option is to lower the outlet of the toilet bowl into the sewer socket, and cover the gap with cement mortar. But it's better to put on the issue first rubber cuff, as in the first case. Instead of cement, you can use any sealant.

It happens that the toilet is located far enough from the place of docking with the sewer or is turned at an angle with respect to it. AT similar situation can only help corrugation. The corrugation will also come in handy if the outlet of the toilet bowl does not reach the junction due to the thick floor covering, for example, tiles.

At the moment, cast iron pipe materials are used mainly for the installation of sewers in public buildings and industrial enterprises. But even in residential buildings, risers are mounted from these materials, especially in high-rise buildings. Installation of the pipeline is laborious due to the large weight and the need to create joints right at the installation site. And it is almost impossible for a non-specialist to create coupling joints.

A truly significant communication system for any living space is sewerage. It is what is required for a comfortable life of a person. For this reason competent installation, involving the connection of sewer pipes of different diameters (or the same), is so important.

1 Connecting sewer pipes with your own hands using detachable elements

A modern sewer system is understood as a complex of various sanitary installations and pipelines of different diameters, which are necessary for the effective withdrawal Wastewater from a house or apartment.
All connections for sewer pipes can now be one-piece or detachable.

Detachable options for connecting pipeline elements are divided into coupling and flanged. Coupling technology is recommended for pressure and non-pressure. Work on the installation of couplings in the arrangement of sewerage networks is carried out according to the following scheme:

• the ends of the products that want to be combined into one whole are cut at an angle of 90 degrees;
• the coupling is applied to the junction, while its central zone should fall on the junction of tubular products;
• after that, markers are applied to indicate a clear location of the connecting element on the pipes;
• the inner surface of the coupling and the ends of the pipes are treated with a lubricant with special properties;
• one of the pipes is inserted into the coupling to the limit (the process is quite easy due to lubrication).

Then the installation of the connected products is carried out. This should be done so that their axis (longitudinal) is one. The coupling connecting for sewer pipes during docking is pushed onto the second part of the structure to the mark applied earlier. This process can be considered completed.

When connecting pipes made of polyvinyl chloride, a flange method of mounting communications is usually recommended. It assumes that cast iron flange fasteners with a mandatory gasket made of rubber material will be used. In this case, the workflow is as follows:

• the pipe is cut off in the connection zone (it is not necessary to make a chamfer, but it is important to achieve an absolutely even cut);
• a free flange is put on the resulting cut;
• the rubber gasket is mounted so that it protrudes from the cut by about 10 centimeters;
• a flange element is applied to the gasket, after which it is connected to the counter flange using bolts of the appropriate diameter.

Tighten the bolts carefully, but without excessive force.

2 How to connect sewer pipes using a one-piece method?

One-piece types of pipeline connections include gluing and welding of individual structural elements. Gluing pipes is carried out using a special adhesive, which is designed specifically for such purposes:

• 88N - "rubber plus rubber" or "rubber plus metal" system;
• BF-2 - glue for metal and plastic products;
• epoxy composition - used when working with polymer and steel parts.

Most often, gluing is resorted to in cases where it is required to connect PVC pipes to each other. The process itself in this situation is performed as follows:

• areas that want to be combined are sanded and then degreased with a product containing methylene chloride (this composition not only removes unnecessary fat from the surface of the pipes, but also slightly dissolves them, which helps to obtain a durable and high-quality communication connection);
• glue is applied to the edges of tubular products treated in this way using a brush or swab;
• the pipes are combined with each other (inserted one into the other), if all the work is done correctly, a little adhesive will appear at the junction.

Professionals advise for greater tightness to additionally treat the joint with an adhesive.

The advantage of this type of connection is that sewer system it is allowed to operate literally immediately after all measures for gluing pipes are carried out. At the same time, during the execution of work, it must be remembered that in the air a special adhesive composition very quickly loses its adhesive characteristics. They remain unchanged for no more than a minute and a half. In this regard, the fastening of pipes should be carried out without delay after the adhesive has been applied to their surface.

The high reliability of the operation of the sewer system is also ensured by the welding of the pipes of which it consists. Nowadays, welding procedures are performed either in a socket or butt. In the first case, the welder simultaneously melts both the inner part of the socket of one tubular product and the smooth outer end of the other, and quickly connects the elements of the system.

Butt welding is performed by heating welding machine ends of pipes and their reflow. The procedure for connecting pipeline parts is carried out under a certain pressure.

It is clear that welding requires special equipment, which not everyone has. home craftsman. And not all types of modern welding technologies can be used for installation of sewerage in residential premises. Usually, electric gas or arc welding is used for homework.

The process of welding the components of the sewer system itself is preceded by cleaning the oily sections of the pipes according to the following scheme:

• the inner surface of tubular products is treated with a solution of caustic soda (ordinary caustic soda);
• then it is necessary to wash off the solution with a copious amount of slightly warmed water.

It is also required to cut off the edges of the pipes with a file and rinse them with a solvent.

Arc welding is performed using tungsten or carbon (the former are non-consumable, so it will be necessary to choose the right additive for them). In gas welding, which is optimal for joining polymer and metal pipes, the use of filler material is mandatory. This is the wire. It is laid in the gap between the surfaces to be connected.

If you don't want to use cement mortar, the connection of pipes made of cast iron is allowed to be performed with high-strength bituminous mastic, asbestos-cement substances, silicone-based sealant.

The use of couplings and adapters solves the problem of combining plastic (highly in demand at present) pipes with cast iron pipes. With their help, it is easy to connect any products with different diameters and from various materials. In this case, it is important to thoroughly clean the socket from the inside, dry it, treat it with a sealant (silicone) and insert the selected adapter into the socket.

If the main element that your new sewer will consist of is a plastic pipe, the cast iron pipe must be removed. Or at least cut it down as much as possible.

Why change

Soviet plumbing was uncomplicated and monotonous. A tiny toilet with a cast-iron riser in the corner, a bathroom next to it, another riser in the kitchen, that's it. But times are changing, there are new ideas in planning, new plumbing and new requirements for it.

All currently produced plumbing fixtures are unified and adapted for attaching plastic pipes to them. Their design does not provide for the use of cast iron sewer pipes. Plastic has a lot of advantages. It is much lighter than cast iron, easy to install and much more economical than a steel or cast iron pipe..

plastic pipes for sale various lengths, with ready-made branches and corners. Each of them has a socket for tight and reliable entry of one pipe into another. All this allows you to assemble the entire sewer system in just a few minutes. Thanks to this simplicity, it is possible to put other plumbing, while slightly changing its location. But there is one problem that cannot be avoided. Through the whole multi-storey building common from top to bottom cast iron riser. And there is a need to make the transition from cast iron to plastic.

How to go

How to connect cast iron sewer pipe with plastic, while ensuring the reliability of the connection? This can be done in several ways.

The simplest is the connection through a rubber adapter. The size of the pipes is standard, and therefore this transition provides that a plastic pipe will be tightly inserted into it, and it will hermetically enter the cast iron one. Connect your sewer system to the common house in this way quickly and reliably. Unfortunately, this is not always possible.

Connecting a cast-iron pipe to a plastic one using one adapter is possible only when its seat is in perfect condition, smooth, free of cracks and chips.

And this does not always happen. Pipe joints burst from time to time, covered with cracks.

Chasing with winding

It may happen that the diameters of the pipes to be joined do not match each other, or the condition of the inner surface of the socket of the cast-iron pipe does not allow the use of such a method. In this case, they use the good old "chasing" method, with the help of which they used to connect cast-iron pipes. This will require sanitary linen winding.

The joints are prepared as follows: the inside of the cast-iron pipe is carefully cleaned, and the end of the plastic pipe is wrapped with several layers of winding. Then we insert one pipe into another. What happened is a weak and unreliable connection.

It needs to be sealed. The winding is folded into a kind of bundle or rope, which is pushed in a circle with a thin spatula into the gap between the pipes. The joints are clogged to about 2/3 of the depth, while trying to ensure the maximum packing density. The remaining space is filled with a mixture of cement, glue and water.

Difference from old methods

AT Soviet times before connecting the cast-iron pipe, the sulfur mass was heated and the cracks were filled with it. But this is very dangerous for health, so more civilized methods are now being used.

It will not be possible to immediately connect the resulting connection to work, you will have to wait for the cement to harden, but the joint made using this technology is strong, reliable and simple.

Very often, at present, even winding is not used to resolve the issue of how to connect a plastic pipe to a cast iron pipe. Construction stores abound different kind sealants. It is a silicone that fills well free space joint, securely sticking to the walls. At the same time, it does not harden completely, remaining moderately plastic. Due to this, the joint is insensitive to vibration and slight bending loads.

Connect pipes from different materials possibly. Sometimes this is done quickly, sometimes you have to tinker, but this work is quite within the power of any masterful owner. Therefore, if you have new ideas for the placement of plumbing, then you should not be stopped by the lack of a sewer outlet near your chosen place. This is a solvable problem. You simply make the transition from cast iron to plastic and make the wiring you need.

Cast iron pipes are widely used in the construction of water conduits and water networks. These pipes are durable and resistant to corrosive environments due to their high corrosion resistance cast iron and significant pipe wall thickness.

Industry produces:

cast-iron socket pipes made of gray cast iron by centrifugal and semi-continuous casting with diameters of 65–1000 mm and a length of 3–10 m;

cast iron pressure pipes with socket butt joints on rubber cuffs and socket-screw connections on locking couplings and rubber rings with diameters of 65 - 300 mm, length 2 - 6 m.

Depending on the working pressure, these pipes are divided into three classes: LA (1 MPa), A (1.4 MPa) and B (1.6 MPa);

cast iron pressure pipes with nodular graphite and butt joints for rubber sealing collar diameters 65 - 600 mm, length 7 m.

Cast iron pipes are interconnected by joints. On fig. 31, a shows the joint of cast-iron pipes with asbestos-cement embedding. With such a connection, the smooth end of one pipe is inserted into the socket of the other, filling the resulting annular space with sealing materials. First, the annular space is caulked with a hemp resin or bituminized strand, compacted special tool and creating a watertight joint; filler is introduced into the rest of the socket, which gives strength to the joint. As a filler, asbestos cement, lead and other materials are used. The best filler is asbestos cement or lead (the latter is used for emergency work). Asbestos-cement filler consists of 30% (by weight) fluffy elastic asbestos fiber and 70% pure Portland cement grade not lower than 400 with the addition of 10 ... 12% (by weight of the mixture) of water. The mixture in the socket is compacted in layers by chasing. Hydraulic tests such connections can be made no earlier than after 12 ... 24 hours. Therefore, when repair work When the plumbing needs to be immediately subjected to internal pressure, lead is used as a filler.

Work on such sealing of the butt joint of cast-iron pipes is quite laborious and requires highly skilled workers. A more industrial is a socket connection with a rubber sealing cuff (Fig. 31, b). In this case, the joint is mounted according to the pressing method. A rubber cuff is installed in the socket, the smooth end of the other pipe is coated with graphite-glycerin grease to reduce installation forces. Then, using a simple device, it is inserted into the socket. Such a butt joint is equally strong with pipes, less laborious in installation, increases the tightness and flexibility of the joint and withstands pressure up to 4 MPa.

On fig. 31c shows a socket-and-screw connection with a rubber ring seal. The ring is kept from rolling out of the socket slot by a screw cast-iron or plastic sleeve.