Air plugs inside the heating system interfere with the normal circulation of the coolant and the full heating of the batteries. To remove these bubbles, two types of stop valves are used - an automatic float air vent and a Mayevsky hand valve, whose device and principle of operation we will consider in the framework of this publication.
Design and principle of operation
First of all, we will explain what a Maevsky crane is - a service valve designed for manual air bleeding at certain points in the heating system. The modern faucet sample shown in the drawing includes the following details:
- nickel-plated brass body;
- locking screw with a tapered tip;
- nylon cap with outlet;
- O-ring made of plastic or EPDM rubber.
A calibrated hole with a diameter of 2 mm was drilled at the end of the body, and a connecting pipe thread was made outside. Inside the housing there is a camera with a lateral exit, where the locking conical screw is screwed.
The crane works on the principle of a needle valve - when the screw is tightened, the main hole is sealed by a cone-shaped tip. To ventilate the system, the screw is unscrewed, the cone opens the passage section, then air together with water comes out through the side channel. The position of the outlet is adjusted by rotating the plastic cap.
History reference. The manual air separator was invented by the Russian engineer Ch. B. Mayevsky in the 30s of the last century. The invention replaced conventional water valves used to remove air congestion from district heating networks. Installation of new taps made it impossible for unauthorized removal of hot water from the system.
What the old Soviet Maevsky valve looks like is shown in the diagram. The official name of the sanitary element is a needle-type radiator air valve type STD 7073V.
Technical characteristics of Maevsky air separators used in water heating systems of private and apartment buildings:
- maximum working temperature - 120 ° C;
- liquid medium - prepared water or non-freezing coolant (antifreeze);
- working pressure - up to 10 Bar (1 MPa);
- connecting dimensions of pipe thread - ¼ ”, ½”, ¾ ”, metric - M10 pitch 1 mm;
- the service life of a quality brass product is at least 30 years.
Note. For more extreme operating conditions, there are crane models designed for a pressure of 16 Bar (marking according to GOST - Ru16) and a temperature of the liquid medium of +150 degrees.
Scope and types of cranes
Mayevsky manual valves are used for such purposes:
- First of all, the removal of air bubbles from all types of heating radiators - aluminum, steel and cast iron.
- Discharge of air from heated towel rails.
- Periodic airing of problem areas of the heating network - expansion joints deployed upwards, bypass loops (for example, above the front door), risers and other places where air accumulates.
Installation of taps for venting is provided by all manufacturers of modern radiators. Heating devices from the factory are equipped with futors (plugs) with an opening for the Majewski valve. The battery valve is selected according to the diameter of the external pipe thread - G¼ ”, ½”, ¾ ”.
Reference. The external G¼ ”thread of the air valve is identical to the fitting of a standard pressure gauge.
If you need to organize air bleeding on a problematic part of the system, a Soviet-style valve with an external metric thread M10 x 1 is bought. The pipe wall is drilled with a Ø9 mm drill, a thread is cut with a tap, then a Mayevsky tap is screwed with a joint seal with plumbing flax.
Another option is to insert a tee into the trunk and install a spline valve on the branch pipe, as is done below in the photo. The method will help with a cold (airy) heated towel rail, in which there is no thread for an air vent.
The principle of operation of all Mayevsky valves is the same, but products found on sale may differ structurally:
- The shut-off valve is made for a slotted screwdriver, a special key or is equipped with a handle. In the old version of the product, a hex bolt was used.
- The needle (cone) blocking the hole is either metal or plastic.
- Designed cast-iron batteries are equipped with the corresponding "aged" valves shown in the photo.
Cranes with a handle are convenient to use - air is easy to bleed without any tools. On the other hand, anyone can turn the valve, including small children, which should not be allowed. Hence the recommendation - buy and put traditional products with a slot or a tetrahedral key.
Reference. Manufacturers equip Mayevsky air vents with some models of ball valves. Here, the version with the handle is more appropriate, and the valve with the G¼ ”thread can be removed and replaced with a pressure gauge or a plug can be installed.
Do not confuse "Mayevsky" with automatic float-type air sprays. The latter are similar in principle - the passage hole is also closed with a needle, but they remove air without human intervention. There are 2 types of such devices - universal (used in boiler safety groups) and radiator ones.
Installation of "Mayevsky" on a cast-iron battery
The installation of drain valves on the legs of aluminum and steel radiators is quite simple and does not require a detailed description. The valve with a rubber ring is neatly pulled by a small key force, then the nylon cap is rotated in the desired direction. The valve with a wide plastic ring and a hole in the metal casing is immediately fixed in the required position - with an outlet fitting downwards.
Another thing is the installation of a valve in a cast iron radiator plug type MS-140. Some craftsmen arrange a makeshift faucet - drill a drill, cut a thread and screw a simple bolt. The option is extremely primitive and inconvenient - an uncontrolled leak forms when the bolt is loosened and the air is blown off.
How to install "Mayevsky" without twisting the sticky twinkle:
- Buy an old-style crane with a M10 x 1 mounting thread and be sure to prepare the appropriate taps - number one and two. The so-called machine tap will not work - cast iron is too hard, the tool will simply break.
- Empty the heater and drill the top plug first with a thin drill, for example, Ø5 mm.
- Carefully break the hole with a Ø9 mm drill, then remove the chamfer for a confident tool entry.
- Cut the thread by passing the hole in taps one and two taps one at a time. Check how well the valve is screwed in.
- Sealing the thread with linen, tighten and tighten the valve with medium force.
Tip. Cast iron drilling and threading should not be done “dry”. Be sure to lubricate the tool with engine oil, otherwise the working edge will quickly become dull.
In conclusion - how to use the valve
During normal operation of water heating, manual "air vents", as a rule, are inactive. Devices open in two cases - during the process of filling the system with coolant or due to airing of the network section (battery). How it's done:
- Prepare a rag and a small container, such as a cropped plastic bottle.
- Substitute the container to the outlet of the drain channel and open the Mayevsky screw by 1 revolution.
- Wait until air comes out (partially with water). An even stream of coolant should go out of the hole.
- Screw on the valve, wipe off spilled water.
Filling the pipeline network and batteries is best done together - the first contractor monitors the pressure and pumps water, the second is engaged in bleeding air from radiators.