When is pressing done
Work related to testing and verification of the system is carried out in such cases:
- upon completion of installation and commissioning of the system;
- after repair of any heating device;
- when replacing parts of the pipeline;
- in preparation for the heating season.
By the nature of the test work, pressure testing is a test for tightness. What it is?
They measure the instantaneous speed of each wheel and, in the event of braking, the deceleration of each tire is calculated to assess its tendency to lock up. Once the danger has passed, the initial pressure will be restored. Acceleration This is the quantity that relates the change in speed with time and is measured in meters per second squared. This is the result of averaging the measurements in both directions of acceleration to the maximum capability of the vehicle on a fixed horizontal reference. When the speed decreases, we speak of negative acceleration.
Let's say that this procedure involves the following steps:
supply to the system under pressure of water or air by a hydraulic or pneumatic pump;
- detection of violations of the tightness of the system;
- determination of places of penetration outside the system of water or air.
Modern type systems make it possible to carry out such tests without involving a large number of personnel. Violations of tightness are determined by special equipment.
Who does the pressing
Intake This is the first time of a four-stroke engine cycle during which air is supplied to the diesel engines or the air/gasoline mixture in the cylinders. The suction that the piston creates when it is deflated causes the mixture or fuel to enter the cylinder. When the suction time does not meet the point indicated on the engine diagram, it is referred to as retarded consumption. In this case, the piston starts to descend when the intake valve is not yet open. During this cycle, the crankshaft rotates half a turn.
When excess pressure is created inside the system, faulty devices, components and emergency sections will become unusable. The operability of suitable elements of the system does not suffer from such a check.
Sequence of work
Pressure testing and flushing of heating systems is carried out after turning off the entire system and removing the coolant (water or antifreeze) from it. When carrying out such a check, it becomes necessary to control the pressure indicators to prevent a rupture of the main pipeline.
It's handy to know that there is a variable type of intake that is increasingly being used that is used to improve filling of the cylinders regardless of RPM. There are two types of variable intake manifolds: the most widely used are variable length multi-plate machines in which electronically controlled butterflies adjust the flow of air or mixture so that long and narrow passages are used at low speeds rotating, wide and short when the beat is brighter.
Thus, the ratio of the length and diameter of the pipeline decreases as the linear speed of the piston increases. The second type are resonant variable intake manifolds, in which the pressure waveforms are synchronized when the air in the manifold hits a closed valve. By manipulating said wave pickups to be shifted towards each other just as the valve is about to open, filling of the cylinders is improved.
What features of the heating system are taken into account when determining specific test parameters:
- pipeline characteristics (material, wall thickness);
- reinforcement characteristics;
- number of floors;
- wiring type.
Pressure testing and flushing of the heating system includes the following preparatory work:
Airbag Airbag in English. In a severe collision, this airbag inflates 30 thousandths of a second or less on the passenger - or their side - in the case of side airbags - to prevent them from being hit by the hard parts of the car's interior. The bag deflates again in tenths of a second once its cushioning mission is reached. The system is activated when a series of deceleration sensors detects that an accident has occurred. Thus, a signal is sent to the electronic control unit, which is responsible for activating the mechanism.
- prevention and preparation of the system;
- directly carrying out work to create pressure inside the system;
- registration of documentation on the work carried out;
- flushing the entire heating system.
Heating system test equipment
Most often, a pressure tester is used to perform a hydraulic test. It is connected to the circuit to regulate the pressure in the pipes.
A huge number of local heating networks in private buildings do not need high pressure, therefore a manual presser will suffice
. In other cases, it is better to use an electric pump.
The operation of the heating system must be not only efficient, but also reliable. To ensure this, it is necessary to correctly select the installation scheme, components and consumables. According to the rules, the final installation or launch event is testing of heating systems: hydraulic, thermal, pneumatic.
Who does the pressing
The next logical question is: who carries out pressure testing of the heating of the building?
The responsibility for the prevention of heating systems rests with the enterprises, institutions and organizations that operate it.
For example, in residential buildings, pressure testing is carried out by public utilities workers, administrative and industrial premises are tested by services that carry out maintenance of these premises.
In principle, such work can only be carried out by certified personnel (heating system pressure tester) using special equipment. Do not crimp by hand.
At the elevator, heating unit in each building, a drain cock is installed on the main line, through which the system is filled with coolant, and then it is drained. Air is released from the upper points of the system through air vents. After that, a pressure test pump is connected to this tap.
The pressure under which the system is tested
The pressure under which the tightness of the system is checked depends on its working pressure. For example, in a system with cast iron batteries in an apartment building, the pressure, as a rule, reaches 2-5 atmospheres. But in a country house or cottage, the working pressure is set to no more than 2 atmospheres. When it rises above this value, excess pressure is released through the emergency relief valve.
The procedure for crimping can be found on the video:
When carrying out pressure testing of new systems, the pressure is increased twice compared to the working one. During repeated checks, it is enough to increase the pressure in the system by 20-50%
from a worker.
Based on the list of work performed, an estimate is made for pressure testing of the heating system. At the same time, data from the reference book-classifier of types of economic activity, products and services (OKDP) are taken into account.
Conclusion
The pressing process itself is a complex technological process. You should not carry it out on your own, it is strongly recommended to use the services of specially trained teams.
On the basis of the normative documentation given below, a pressure test report was developed, which is one of the main documents when the work is handed over to the Customer at the facility.
Heating networks must be subjected to annual hydraulic strength and density tests (pressure tests) to identify defects after the end of the heating season and carry out repair work. Pressure testing of pipelines available for inspection during operation is allowed to be carried out 1 time after installation is completed.
Hydraulic pressure testing is carried out with a test pressure of 1.25 working pressure, but not less than 1.6 MPa (16 kgf/cm2). Pipelines are kept under test pressure for at least 5 minutes, after which the pressure is reduced to working pressure. At operating pressure, a thorough inspection of pipelines along their entire length is carried out. The results of pressure testing are considered satisfactory if during its implementation there was no pressure drop and no signs of rupture, leakage or fogging were found in valve bodies and stuffing boxes, in flange connections, etc.
Before the start of the heating season, after the end and hot water supply, the following must be subjected to hydraulic pressure testing for strength and density:
Elevator units, heaters and water heaters for heating and hot water supply —
pressure 1.25 working, but not lower than 1 MPa (10 kgf / cm2);
Heating systems with cast iron heaters -
pressure 1.25 working, but not more than 0.6 MPa (6 kgf / cm2);
Panel and convector heating systems —
pressure 1 MPa (10 kgf/cm2);
Hot water systems -
pressure equal to the working pressure in the system plus 0.5 MPa (5 kgf/cm2), but not more than 1 MPa (10 kgf/cm2).
Hydraulic testing should be carried out at positive outside temperatures. At outside temperatures below zero, a density test is only possible in exceptional cases.
Systems are considered to have passed the test if, during their implementation:
No “sweating” of welds or leaks from heating devices, pipelines, fittings and other equipment was found;
During pressure testing of water and steam heat consumption systems for 5 minutes. the pressure drop did not exceed 0.02 MPa (0.2 kgf/cm2);
During pressure testing of surface heating systems, the pressure drop within 15 min. did not exceed 0.01 MPa (0.1 kgf/cm2);
When pressure testing hot water systems, the pressure drop for 10 minutes. did not exceed 0.05 MPa (0.5 kgf/cm2).
The results of the check are documented in an act of pressure testing. If the results of the pressure test do not meet the specified conditions, it is necessary to identify and eliminate leaks, and then re-check the tightness of the system. During hydraulic testing, spring pressure gauges of an accuracy class of at least 1.5 should be used, with a body diameter of at least 160 mm, a scale for a nominal pressure of about 4/3 of the measured one, with a division value of 0.01 MPa (0.1 kgf / cm2), verified and sealed by the sovereign.
Updated: 08.08.2018
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