The selection of guide trap
On the British royal chemical industry company is located in the Huddersfield and Grangemouth (England) industrial factory trap performance monitoring and the seven-year experiment, the two primary producers laboratories trap performance and fresh steam loss monitoring and on the basis of experiment, the royal chemical industry company of the final project design guidance of relevant trap content changes have been made.
Old criteria for selection has many shortcomings, the most obvious is that it did not mention is hydrophobic equipment types and hydrophobic method. Selected trap often to the actual load don't match. Especially serious is, thermodynamic disk trap (selection standards of old people, especially the workshop personnel for universal trap.
Early in 1980, due to the maintenance staff complain competent steam trap life is too short, Grangemouth factory began to trap performance monitoring. Two years later, Huddersfield factory to do the same.
In monitoring, the first to trap, understand the existing trap types, and the selection of load test. Also the test. Preliminary results are shocked. For a workshop in the trap 415 only doing results show that 19% trap has effect, 63% of load selection does not match.
In charge of the steam trap 132 only do that 42% of the trap has effect. The life of the trap test also began in 1980 and continues today. Table 2-1 lists various traps life expectancy.
For all kinds of trap of energy-saving benefit, the two producers in the laboratory is the use of the fresh trap test steam loss. In laboratory tests, namely, the static air 20 degrees centigrade. This experiment fails to trap the heat loss of the valve body. Detection of condensate load for common 10-20 kg/hour (22-44 pounds per hour). Test results in summary table 2-2. The two forms of the most interesting thing is, as the widespread adoption of thermodynamic dise-type trap, the worst, and energy saving effect and the bucket compared to trap, life is very short.
In the heat of the requirements of high heat, with static trap instead of thermodynamic disk trap will improve energy saving effect, and longevity.
These experiments also reveals the mechanical trap (i.e. down the bucket and float trap) in condensate load or load small situations can ensure steam condensate, and heat does not contain trap in the static load increases easy accumulation condensate. In addition, dual metal trap to unstable action.
After the new guidance law includes trap.
Now the selection recommended:
Pour the bucket trap:
As all the process load line and steam trap, namely, the choice of steam trap for all occasions.
Float hot static trap:
Used to craft hydrophobic, especially in the control (50psig under load 3.5 kg) applications or air content high, the installation of the bucket down trap has problems.
Balance pressure steam trap:
For not important heating or heating system.
Dual metal hot static trap:
Used for heating pipelines or heating system is low or frost prevention. This type of trap to maximize the use of condensate of sensible heat or prevent overheating. The body as a whole stainless steel.
Thermodynamic disk trap:
As in previous experience prove its performance is good, can be used as the bucket down trap alternative products, under pressure to 17 kilograms of steam competent and under the limited use of heat, or as a product substitution for higher steam pressure. Because of its energy efficiency is low, service life is short, don't recommend use (and, in Grangemouth Huddersfield and factories are not allowed to use).
| 表2-1. the average useful life for traps | |||
| type | high pressure 4.5mpa（650psig） |
middle pressure 1.4mpa（200psig） |
low pressure 0.2mpa（30psig） |
| therm o-motive disc traps | 10-12 months | 12 months | 5-7 years |
| floating-ball hot-static force traps | …… | ×1-6 months | 9months－4 years |
| inverse bucket traps | 18 months | 5-7 years | 12-15 years |
| pressure balancing traps | …… | 6 months | 5-7 years |
| bimental plate traps | ×3-12 months | 2-3 years | 7-10 years |
| × submit to model | |||
| 表2-2. 新鲜蒸汽损失－公斤／小时（磅／小时） | ||
| 疏水阀类型 | 中压 1.4mpa（200psig） |
低压 0.2mpa（30psig） |
| 热动力圆盘疏水阀 | 1.09（2.4） | 0.84（1.9） |
| 倒吊桶疏水阀 | 0.44 | 0.42（0.93） |
| 压力平衡疏水阀 | 未测 | 0.10（0.22） |
| 双金属片疏水阀 | 无 | 无 |
| 半冷却式双金属热静力疏水阀 | 无 | 无 |
Trap guidelines
The trap must choose the best quality products, to the limited funds in the blade. Using high quality trap had to save energy and to improve production efficiency than buying the trap of investment to a few times. Choose good quality traps can bring huge economic benefits. The trap of large amount of wide use, must not ignore, competent leadership should be highly valued.
Select trap requirement accurate steam to resistance, high sensitivity, drainage, can improve the utilization of steam leakage steam, reliable performance, high rate of back pressure, long service life, convenient maintenance is preferred.
1 in the production process of heat exchange equipment, drying chamber, rapid heat exchanger, distillation equipment, not allowed to rapid increase in production of condensate entities heating, should choose mechanical type of trap.
Mechanical type of trap from working temperature and pressure changes, water namely, subcooling small, standing in heating equipment, can make the heating equipment to achieve the best working temperature. One free float type steam trap is the most advanced structure, very sensitive, minimum subcooling 0 ° C, be saturated steam leaking water temperature, maximum advantage, and can make the heating equipment to achieve the best work efficiency. Is the most ideal heating process of trap.
The steam pipe, heat pipes, heating equipment, small heating equipment, the high temperature steam equipment, should choose hot static type of trap.
Static type of trap heat, cold water line of low temperature, high temperature can make full use of the condensate, energy-saving thermal effect is good. Which film cassette steam trap structure is the most advanced, manual adjustment, very sensitive, the greater is 15 degrees c and cold 30 ° c for two membrane box type, afraid of cold, small volume, arbitrary position can be installed in the pipeline, can repair and replacement valve spool, save money and labor, long service life, the applicable range is very wide, is hot static type of trap.
3 in high temperature and high pressure steam pipeline and equipment on overheating, should choose special superheated steam trap.
Overheating steam trap in high temperature and high pressure and the bad conditions isolated superheated steam temperature disappeared when the water. One dise-type steam trap heat pipe type of using steam trap of main steam room for insulation, advanced structure, no water in the circumstances, the trap tightly closed, quality high, long service life, high superheated steam special trap.
