The profile throttle is much superior to the orifice plate when measuring medium which is easy to stain, wear and deform the throttle parts.
In order to select the most suitable standard throttle device, the selection should be considered from the following aspects:
① The limiting conditions of the diameter ratio and the Reynolds number range;
② measurement accuracy;
③ allowable pressure loss;
④The shortest straight pipe length required ;
⑤The sensitivity of to the erosion, wear and stain of the tested medium;
⑥ The complexity and price of the structure;
⑦The convenience of installation;
③Long-term stability of use.
According to the above aspects, the standard throttle device selection principle can be summed up as the following points.
① standard throttling Device the size, diameter ratio and Reynolds number range of various types of throttle applications are limited in the national standard GB 2624-93 (or international standard ISO 5167-1), for example, the orifice plate can be applied to a larger diameter range than the nozzle and venturi nozzle, Different types of classic venturi tube diameter range of large differences and so on.
② Standard throttle Device The accuracy of various types of throttle is determined by the uncertainty of outflow coefficient and expansibility coefficient under the same differential pressure and density measurement precision. The uncertainty of the outflow coefficient of various kinds of throttle is different, in contrast, the uncertainty degree of orifice coefficient is the smallest, and the profile throttle (nozzle, venturi tube) is larger. The larger reason of profile throttle is the poor quality of the fitted database according to the formula of outflow coefficient given in the standard. However, a high accuracy can be obtained by the individual calibration of the profile throttle.
③ under the same differential pressure, the pressure loss of classical venturi tube and venturi nozzle is about 1/4~1/6 of orifice plate and nozzle. The pressure loss of the nozzle is only the 30%~50% of the orifice plate at the same flow rate and the same beta value.
④In the case of the same type and diameter ratio, the necessary straight pipe length of the classical venturi tube is much smaller than that of the orifice plate and the nozzle.
⑤ The profile throttle is much superior to the orifice plate when measuring medium which is easy to stain, wear and deform the throttle parts.
⑥ in the processing of manufacturing and installation, the most simple orifice plate, nozzle second, venturi nozzle and classic Venturi tube is the most complex, the cost is also increasing in turn. The greater the diameter of the pipe, the more remarkable the difference.
⑦ Orifice Plate Easy to check the quality of the throttle piece (using the orifice plate throttle device), the nozzle and venturi tube will need to truncate the fluid, remove the pipe can be inspected, more trouble.
③ Small-caliber (dn50~-DN100) throttling device, the impact of the size of the pressure and the position of the pressure is significant, when the use of the ring chamber pressure has a certain advantage.
Please visit our website:www.aft-flowmeter.com,if you want to know more.
① The limiting conditions of the diameter ratio and the Reynolds number range;
② measurement accuracy;
③ allowable pressure loss;
④The shortest straight pipe length required ;
⑤The sensitivity of to the erosion, wear and stain of the tested medium;
⑥ The complexity and price of the structure;
⑦The convenience of installation;
③Long-term stability of use.
According to the above aspects, the standard throttle device selection principle can be summed up as the following points.
① standard throttling Device the size, diameter ratio and Reynolds number range of various types of throttle applications are limited in the national standard GB 2624-93 (or international standard ISO 5167-1), for example, the orifice plate can be applied to a larger diameter range than the nozzle and venturi nozzle, Different types of classic venturi tube diameter range of large differences and so on.
② Standard throttle Device The accuracy of various types of throttle is determined by the uncertainty of outflow coefficient and expansibility coefficient under the same differential pressure and density measurement precision. The uncertainty of the outflow coefficient of various kinds of throttle is different, in contrast, the uncertainty degree of orifice coefficient is the smallest, and the profile throttle (nozzle, venturi tube) is larger. The larger reason of profile throttle is the poor quality of the fitted database according to the formula of outflow coefficient given in the standard. However, a high accuracy can be obtained by the individual calibration of the profile throttle.
③ under the same differential pressure, the pressure loss of classical venturi tube and venturi nozzle is about 1/4~1/6 of orifice plate and nozzle. The pressure loss of the nozzle is only the 30%~50% of the orifice plate at the same flow rate and the same beta value.
④In the case of the same type and diameter ratio, the necessary straight pipe length of the classical venturi tube is much smaller than that of the orifice plate and the nozzle.
⑤ The profile throttle is much superior to the orifice plate when measuring medium which is easy to stain, wear and deform the throttle parts.
⑥ in the processing of manufacturing and installation, the most simple orifice plate, nozzle second, venturi nozzle and classic Venturi tube is the most complex, the cost is also increasing in turn. The greater the diameter of the pipe, the more remarkable the difference.
⑦ Orifice Plate Easy to check the quality of the throttle piece (using the orifice plate throttle device), the nozzle and venturi tube will need to truncate the fluid, remove the pipe can be inspected, more trouble.
③ Small-caliber (dn50~-DN100) throttling device, the impact of the size of the pressure and the position of the pressure is significant, when the use of the ring chamber pressure has a certain advantage.
Please visit our website:www.aft-flowmeter.com,if you want to know more.
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