Some standard content:
Sight glass plate liquid level gauge (PN0.6)
HG 21591: 2-95
1 Subject content and scope of application
1.0.1 This standard specifies the type, size, technical requirements and instructions for use of sight glass plate liquid level gauges. There are three types of sight glass plate liquid level gauges (PN0.6), with a design temperature of 250℃, a design pressure of 0.6MPa, and corrosion margins as specified in Table 1.0.1. Table 1.0.1 Corrosion allowance
Carbon steel I (16MnR)
Stainless steel (0Cr18Ni9)
Carbon steel I (16MnR with lining)
Corrosion allowance (mm)www.bzxz.net
Reference standard
HG21588-95 "Standard series and technical requirements for glass plate liquid level gauges" 56
3.·Structural type, basic parameters and dimensions 3.0.1 The structural type and dimensions of this standard are shown in Figure 3.0.1-1, Figure 3.0.1--2 and Table 3.0.1.
Table 3.0.1 Specifications, basic parameters and dimension markings of sight glass plate liquid level gauge (PN0.6)
Liquid level gauge S0.6--1.Q
Liquid level gauge So.6—1Q
Liquid level gauge So.6-True Q
Transmittance size
(mmXmm)
304×18
304×18
304×18
Standard drawing (i.e. construction drawing) drawing number
HG 21591. 2 -- 95—1
HG21591.2-95—2
HG21591.2—95--3
3.0.2 The glass plate shall be in accordance with QB776-80 "Glass plate and glass tube for liquid level gauge" standard, with specification number R320.
Q-type sight glass plate liquid level gauge:
Structural diagram
Figure 3.0.1-1 S 0. 6-- 1Q.S 0.6-4
Glass plate
Figure 3.0.12
S0.6-sub Q-type sight glass plate liquid level gauge structural diagram Gasket
Glass plate
Technical requirements
Technical requirements should comply with the relevant provisions of HG21588-95 "Glass plate liquid level gauge standard series 4.0.13
and technical requirements" standard. The lining is carried out with the equipment, and the lining material is alternate with the lining material of the equipment.
5 Selection regulations
Marking regulations and examples shall comply with the relevant regulations in HG21588-95 standard. 5.0.2 The various specifications of liquid level gauges in this standard shall be selected according to Table 3.0.1; and indicated in the detail column of the equipment assembly drawing.
5.0.3 The designer may change the material (asbestos rubber sheet) of the gasket (item number 4), but it shall be stated on the equipment assembly drawing. The changed gasket material is limited to the material with the parameters of specific pressure Y less than or equal to 25.5MPa and gasket coefficient m less than or equal to 2.75. 5.0.4 In order to reduce welding deformation, the size of the fillet weld between the joint edge (item number 1 in Figure 3.0.1-~1 and Figure 3.0.1-2) and the container wall shall be minimized. 62
Additional Notes
Proposer, Editor-in-Chief
and Main Drafters of this Standard
Equipment Design Technology Center of the Ministry of Chemical Industry
Proposer:
Editor-in-Chief: China Huanqiu Chemical Engineering Company Main Drafters
Kong Xianglin
Compiler: Qiu Wenbing
Checker: Liu Menglin
Auditor: Xue Tijun|| tt||Glass Plate Liquid Level Gauge
HG21589.1~-21589.2—95
HG21590—95.HG21591.121591.2—95Preparation Instructions
, Preface
"Glass Plate Liquid Level Gauge" was compiled based on the 1993 design basic work plan issued by the Ministry of Chemical Industry (93) Chemical Basic Standard No. (28). The compilation of this standard is based on the original HG5-1363~1370-80 "Glass Plate Liquid Level Gauge Standard" (hereinafter referred to as the "original standard"), and is carried out after investigating its design, manufacturing and use. After fifteen years of use, the original standard has basically met the needs of chemical and petroleum industry production, and has played a role in indicating the liquid level and guiding production for the production of chemical and petroleum products. However, some shortcomings and deficiencies were also found in use, mainly: when the liquid level gauge breaks, if the stop valve is not installed at the inlet and outlet of the liquid level gauge, the liquid level gauge can only be replaced after stopping production, which brings great inconvenience to production and operation; when the medium is dirty or viscous, blockage occurs from time to time. In recent years, my country has introduced a large number of foreign chemical production equipment. In order to adapt to the development of production and expand the scope of use of liquid level gauges, liquid level gauges should be equipped with standard flanges corresponding to the equipment. In addition, some of the material grades and component standards used in the original liquid level gauge standard have changed significantly, and should also be replaced with new grades and new standards. This standard solves the above main problems. II. Compilation principles and contents
1. About types and structural forms
In order to make the name of the liquid level gauge more intuitive, this standard changes the name of the R6 type and R type liquid level gauge in the original standard to "mirror glass plate liquid level gauge", and the names of other types of liquid level gauges 63
remain unchanged. Therefore, the liquid level gauges in this standard adopt three types: "transmissive type", "reflective type" and "mirror type", and their models are T type, R type and S type respectively. When installing the glass plate liquid level gauge with a connecting flange (T type and R type in this standard) in the original standard, it is necessary to install stop valves at both ends of the inlet and outlet, so that when the liquid level gauge breaks, the liquid level gauge can be replaced without stopping production. This standard has improved the structure to address the above problems. The improved liquid level gauge no longer needs to be installed with stop valves at both ends of the inlet and outlet, and the liquid level gauge can be repaired and replaced without stopping production. It not only simplifies the installation, but also saves stop valves, which brings great convenience to production and maintenance. The R6 type (S type in this standard - PNO.6) liquid level gauge in the original standard is a neck type, and the R type (S type in this standard - - normal pressure liquid level gauge is an embedded connection type. This standard verifies the neck parts of the neck type liquid level gauge and finds that the parts in this part are unsafe in terms of strength when used for 0.6MPa, but safe and reliable when used for 0.1MPa. The surface embedded connection type liquid level gauge has a certain thickness of the edge, which can be used as the shell opening reinforcement (area). Therefore, this standard retains the original embedded connection type in the structural type of the normal pressure liquid level gauge, and adds the neck type, and changes the 0.6MPa liquid level gauge from the original The neck type is changed to the embedded connection type. 2. About the nominal pressure
The nominal pressure of the light-transmitting type (2.5MPa and 6.3MPa), reflection type (4.0MPa), and sight glass type (normal pressure and 0.6MPa) liquid level gauges still adopts the pressure level in the original standard. Among them, 6.3MPa is used instead of 6.4MPa because 64kgf/cm2-6.28MPa, and the HGJ "Steel Pipe Flanges, Gaskets, Fasteners" standard adopts 6.3MPa. In order to be consistent, 6.3MPa is used. The meaning of normal pressure refers to the range of design pressure from zero to less than 0.1MPa.
3. About the use temperature: The use temperature of the glass plate liquid level gauge mainly depends on the material of the glass plate. As for the physical and chemical properties of borosilicate-64
glass, whether it is heat shock resistance, expansion coefficient and tensile strength, it is better than general soda-lime glass, so liquid level gauges at home and abroad all use borosilicate glass. This standard stipulates that the maximum use temperature is 250℃ (medium temperature). For PN4.0.PN6.3 liquid level gauges, when the temperature exceeds 200℃, the use pressure should be reduced. The reason is that through the strength test of the glass plate, it was found that if the tempered glass plate is heated at 200-300℃, its bending strength value will decrease. And the liquid level The gauge standards all use standard glass plates of the same thickness, so only some of the standard pushes involve liquid level gauges that need to be heated and reduced in pressure. For PN2.5, PNO.6 and atmospheric pressure liquid level gauges, since the strength of the glass plate meets the requirements for use at this temperature, they can be used without reducing the pressure at 250°C. For liquid level gauges with lining structures, the operating temperature is the allowable temperature of the lining material, but the allowable temperature of the lining material shall not exceed the maximum operating temperature specified in this standard. 4. Regarding corrosion allowance
The original standard push did not specify the corrosion allowance for liquid level gauges. In order to avoid damage to liquid level gauges due to corrosion, this standard adds provisions for the corrosion allowance of liquid level gauges. 5.About gaskets for liquid level gauges
Flexible graphite composite gaskets are superior to asbestos rubber sheets in all properties and are pollution-free. They have been adopted in the HGI70-91 standard. Therefore, when compiling this standard, flexible graphite composite gaskets were used to replace the asbestos rubber sheets in the original standard for T-type and R-type liquid level gauges. Asbestos rubber sheets are still used for S-type liquid level gauges due to their low design pressure. In order to expand the applicable scope of the medium, this standard also provides regulations that gaskets can be replaced. 6. About flanges for liquid level gauges
(1) Standard for external connection flanges
This standard adopts the newly formulated HGJ "Steel Pipe Flanges, Gaskets, Fasteners" standard, and also adopts the ANSIB16.5 "Pipe Flanges and Flange Fittings" standard, which is a commonly used standard in foreign chemical production equipment. 65
(2) Regarding the flange type used in this standard
Due to the limitations of the operating pressure, operating temperature and the medium used, this standard adopts neck welding flanges.
If other standard flanges are used, they should be negotiated with the liquid level gauge manufacturer and explained in the design documents.
(3) Regarding the flange size and pressure level used in this standard Due to the limitations of the standard HGJ67-91 "Pressure-temperature level of steel pipe flanges", this standard designs flanges for T-type (PN6.3) and R-type (PN4.0) liquid level gauges according to the maximum allowable operating pressure (4.0MPa or 6.3MPa) and operating temperature (200℃) specified in Table 1.0.3 of the standard HG21588-95 "Standard Series and Technical Requirements for Glass Plate Liquid Level Gauges". In order to simplify the design, this standard only gives the flange dimensions under this pressure and this temperature. Under this pressure, this flange is still used when the operating temperature is lower than 200℃, which provides convenience for manufacturing, supply and installation. However, when the operating temperature is higher than 200℃, the maximum allowable operating pressure (without impact) shall be determined according to the provisions of Table 1.0.3 in HG21588--95 standard. The T-type (PN2.5) series is designed for an operating temperature of 250C, and this flange is still used when the temperature is lower than this.
(4) The pressure level of the flange connected to the flange used in this standard is that the operating pressure of flanges made of different materials will decrease when the operating temperature increases, so this standard uses a flange that is one level higher than the nominal pressure of the liquid level gauge. That is:
Liquid level gauge nominal pressure
Pressure level of external connection flange
Because in the HGJ "Steel Pipe Flanges, Gaskets, Fasteners" standard, PN2.5 and 66
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.