Blasting needle valve, also known as buckling needle valve or needle safety valve. It is driven by static pressure from the valve inlet, causing the needle under pressure to become unstable and bend, thereby releasing pressure.

The blasting needle valve was invented by American engineer Julian Taylor in 1986, mainly used to solve the problem of slow release and poor accuracy of pilot operated safety valves. After thirty years of change and development, it has gradually matured and formed an independent safety pressure relief device.

Our blasting needle valve adopts a unique revolutionary design, patented technology, no leakage during discharge, safe and environmentally friendly, solving many of the most difficult problems and achieving high satisfaction rates!

explain:This type of safety equipment needs to be calculated and selected based on the specific operating parameters of the protected equipment and system to better exert its protective effect. Only after selecting the model can a quotation be made. To ensure use, please contact us as soon as possible through online consultation, hotline, online message, email and other methods. Our staff will arrange sales engineers in the corresponding area to provide free calculation, selection, quotation and other technical support services to help you quickly choose suitable products and arrange shipment or production scheduling for you as soon as possible.Xuzhou Bafang Partial Qualification Certification Certificate

Working principle of blasting needle valve

The blasting needle valve is a non reclosing pressure release device invented based on Euler's law. The piston that bears the system pressure acts on the needle with a pre-set buckling force through the valve stem, and the blasting needle bears the pressure from the system piston. When the system's pressure on the piston reaches the predetermined bending force, the valve rapidly bends within a few milliseconds, the piston lifts, and the valve releases pressure.

advantage

·All valve products have zero leakage

·No personnel safety issues

·No product loss

·No environmental pollution

·There are no fragments

·Very precise

·Lower maintenance costs

·Lower cost of replacing blasting needles

·Full caliber release within milliseconds

·Replacing the blasting needle takes only one minute per person

·Extremely short parking time

·High operational ratio, working under pressure very close to the set point

·No need for vacuum bracket

·Only set the import pressure or only set the pressure difference

·The blasting needle is very stable and does not produce fatigue

·No need for complex operations

·The overpressure of the equipment can be determined by the bending of the blasting needle, and proximity sensors can also be used for remote monitoring

·When replacing the blasting needle, there is no need to disassemble the pipeline or valve body

·No need for annual calibration by the pot inspection institute

·After replacing the blasting needle, production can continue

·The delivery time for spare blasting needles is extremely short

·Customize blasting needle valves according to different customer requirements

·Within a few minutes, the set pressure can be changed by replacing the blasting needle

·No need to disassemble pipelines or valve bodies

·Valve reliability can be checked on-site under pressure

·Provide emergency release for the system to ensure safety

·Wide size range, customizable from small to large sizes

·The pressure range is also large, it can be very small or very large, and the same goes for vacuum

The three main components of the blasting needle valve

1- Valve body: a pressure resistant shell, fixed blasting needle and valve internals, mainly made of forgings, with castings made of carbon steel or stainless steel.

2- Piston: A device that withstands system pressure, connected to a blasting needle through a valve stem. The piston has an O-ring, and the corresponding O-ring material is selected according to the pressure, temperature, and size to ensure zero leakage. Under normal working pressure, the piston is embedded in the cylinder of the valve body, and the valve remains closed. When the system pressure rises to the set pressure, the blasting needle bends under the predetermined load, the piston slides out of the cylinder, and the valve opens.

3- Blasting needle: Its function is to set the valve pressure. The blasting needle is in contact with the surrounding atmosphere, does not come into contact with the medium, is not affected by the temperature and corrosion of the medium inside the valve body, and can maintain long-term stability.

Three factors controlling the set pressure of the blasting needle valve

1- Weight and size of the piston

The weight of the piston is converted into pressure on the system due to gravity (which can be ignored if the piston is horizontal), and the size of the piston determines the pressure it experiences at the set pressure.

2- Bending load of blasting needle

According to Euler's law, the load is proportional to the fourth power of the diameter of the blasting needle and the elastic modulus, and inversely proportional to the square of the length of the blasting needle. By adjusting the diameter and length of the elastic modulus needle, the bending load of the top needle can be precisely set.

3- System Friction

The components that generate frictional force in the blasting needle valve mainly include the piston and cylinder, valve stem, and guide sleeve. Before bending, the needle will have a slight protrusion, turning static friction into dynamic friction. The frictional force of these seals will not accumulate and increase over time, and the set pressure of the valve will not drift as a result.

Stress testing

Comparison of blasting needles and blasting discs

In fact, the main disadvantage of blasting discs is that the blasting stress is much higher than the yield stress. The stress-strain curve of the arched (tensile) blasting disc is shown in red in the figure. Once the pressure on the bursting disc exceeds the yield point, irreversible damage will occur. Under normal circumstances, the system pressure always fluctuates beyond the yield point of the material, which can cause premature bursting of the bursting disc, unless the system pressure can continuously increase to the bursting point pressure. Indeed, if the rupture disk is detonated in advance, it is safe for the system, but we also need to consider unnecessary pollution, product loss, downtime, replacement costs of the rupture disk, and labor time consumed. For the blasting needle, the stress change is always within the elastic limit range, and its deformation mechanism follows Euler's theorem. Before reaching the set blasting pressure, the blasting needle will not fail prematurely.

The Effect of Temperature on the Pressure of Blasting Needle Valve/Blasting Disc

The explosive disc device directly contacts the medium and is greatly affected by the temperature of the medium. In industrial production, due to the large temperature range and overpressure range, the bursting disc may not only explode prematurely, but also delay, which poses a great safety hazard.

The pressure control needle of the blasting needle valve does not contact the medium and is only related to the surrounding medium. The allowable deviation between -40 ℃ and -100 ℃ at room temperature will not exceed ± 2%. Therefore, the set pressure of the blasting needle valve is minimally affected by factors such as the medium and temperature inside the blasting needle valve, and there will be no premature or delayed bending. The blasting needle valve has superior precision and stability.

Stress Test

In the pressure tests of these blasting needles, we repeatedly applied a pressure load of 98% of the set point to the blasting needle 9 times in a row, and then on the 10th timeWhen subjected to pressure, it undergoes permanent deformation. Each test fully demonstrated the excellent operational performance of the blasting needle, which can operate in close proximity to the deviceWorking under fixed pressure without the risk of elastic fatigue or premature explosion. The test also demonstrated the precise blasting pressure of the blasting needleSex.

Stress testing shows that although the loading force of the blasting needle varies significantly, the needle will not undergo unstable bending before reaching the set blasting pressure. The blasting needle valve exhibits good fatigue resistance, accuracy, and sensitivity.

A series of tests fully demonstrate the excellent performance of the blasting needle valve in the process of safe pressure relief, and also indicate that the performance of the blasting needle valve is significantly better than other types of pressure relief devices, providing a reliable basis for the wider application of blasting needle valves in the safety pressure relief industry.

The blasting needle valve not only plays a significant role in promoting the development of the domestic and international safety relief industry, but also will drive the market for safety relief devices onto a more brilliant path.

About blasting needles

Blasting needles are centerless ground, with the diameter of the needle precise to the fourth or fifth decimal place to meet strict specifications and a small tolerance range.

The diameter of the blasting needle increases in small increments from 0.2mm to 32mm. It contains three specialized alloys, each with high corrosion resistance and suitable for different environmental conditions. For example, for alloy 3, the ambient temperature of the needle can vary between -100 ° F and+400 ° F, and the change in elastic coefficient will not exceed 0.3%.

The diameter and length of the blasting needle alloy are determined by the optimal aspect ratio of Euler's law.

The friction of the sealing surface and the weight of the piston require slight adjustments to the length of the calculated blasting needle. By conducting a series of tests on each valve and making slight adjustments to the length of the blasting needle, very precise set points are achieved to eliminate deviations. In these testing processes, the blasting needle valve is tested for practical application purposes.

This process may require testing the needle at least 3 to 5 times to obtain the precise length of the needle. Once these tests are completed, the parameters of the needle are determined and recorded.

These needles will be placed inside the valve for three more tests, and the test results and all relevant information will be recorded in the instruction manual for the blasting needle valve. The peak pressure of bending deformation is measured using a standard electronic pressure gauge with an accuracy of 0.01%. This will lock the accuracy of the blasting needle valve to an average between+/-1% and+/-3% of the set point. The additional blasting needles provided are also specially customized for users and tested three times on the compression tester. The test results will be recorded and archived for accurate setting of replacement blasting needles.

Marking of blasting needles

Once the specifications of the blasting needle are determined, each blasting needle will be labeled. This label includes the code of the blasting needle, the serial number of the valve, and the set pressure of the valve. Each valve has a unique serial number, which contains all the information needed to reproduce replacement blasting needles, making the reordering process very simple.

Change in diameter of blasting needle

To demonstrate the impact of blasting needle diameter on performance, we conducted a diameter variable test. We selected 4 different diameters and all needles were cut to the same length of 180.32mm. Then we select 5 samples for each diameter and use compression equipment to determine the ultimate load at the deformation bending point.

In the table of diameter variables, we have listed the average ultimate buckling force for each diameter. As the diameter gradually increases, the performance of the blasting needle has shown a sharp improvement. This indicates that even if the diameter only changes by 0.1693mm, it can still affect the load performance of the blasting needle, which is why we conducted such meticulous testing on the blasting needle.

Length variation of blasting needle

In this test, we selected the same material with the same diameter of 3.1215mm and cut it to different lengths. We tested five samples of each length to determine the ultimate load of the blasting needle. The following table lists the average values for each length.

Standardized design of blasting needles

This intelligent design method allows users to change the set point by simply changing the blasting needle. It is achieved by adjusting the fixing sleeves at both ends of the blasting needle while keeping the overall length of the blasting needle unchanged. The change in set pressure is achieved by varying the diameter and length between the fixed sleeves at both ends of the actual blasting needle. We can therefore meet the various complex design requirements of our clients.

Operation ratio

The pressure operation ratio (maximum working pressure/minimum set pressure) of blasting needle technology can reach 95.0%, and it can be further improved in the future.

Material selection

Valve body: carbon steel, low-temperature carbon steel, stainless steel, special alloy

Valve seat: stainless steel, special alloy

Pistons: Stainless steel and stainless steel stem, special alloy

Shaft sleeve: aluminum copper alloy or stainless steel (aluminum copper alloy as standard), special alloy

seal ring: VITON, BUNA, KALREZ, EPDM or other