1 Scope
This document specifies the type and designation, dimensions, technical requirements, test methods, inspection rules, marking, symbols, ordering information for wound gaskets for pipe flanges (hereinafter referred to as "gaskets") with PN marking. Packaging and storage.
This document applies to wound gaskets for pipe flanges with nominal pressures from PN 10 to PN 250 and nominal sizes from DN 10 to DN 3000 as specified in GB/T9124.1.
2 Normative references
The contents of the following documents constitute essential provisions of this document through normative references in the text. For the dated references, only the version corresponding to the date is applicable to this document; for the undated references, the latest version (including all amendment sheets) is applicable to this document.
GB/T 2054 Nickel and Nickel Alloy Plate
GB/T 3003 Refractory Fiber and Products
GB/T 3274 Carbon Structural Steel and Low Alloy Structural Steel Hot Research Mesh Plate and Strip
GB/T 3280 Cold Rolled Stainless Steel Plate and Strip
GB/T 5019.4 Mica based insulating materials Part 4: Mica paper
GB/T 12385-2008 Test Method for Sealing Performance of Pipe Flanges
GB/T 12,622-2008 Test Method for Compressibility and Resilience of Gaskets for Pipe Flanges
GB/T 27793 asbestos free fiber gasket material
JB/T6618 Technical Conditions of PTFE Tape for Metal Wound Gasket
JB/T 7758.2 Technical Conditions for Flexible Graphite Plate
3 Terminology and definitions
There are no terms and definitions that need to be defined in this document.
4 Type and designation
4.1 Type
4.1.1 Gasket type according to Figure 1 - Figure 4.
4.2 Designations
4.2.1 Gasket type designations are as specified in Table 1.
Table 1 Type designations
5 Dimensions
5.1 Dimensions of basic wound gaskets for flanges with tongue and groove faces
The dimensions of the basic type wound gaskets for tongue and groove face flanges shall be in accordance with Figure 1 and Table 4.
Table 4 Dimensions of basic type wound gaskets for tongue and groove face flanges (Type A)
5.2 Dimensions of the winding gasket with inner ring for flanges with concave and convex faces
The dimensions of wound gaskets with inner ring for flanges with concave and convex faces shall be in accordance with Figure 2 and Table 5.
Table 5 Dimensions of the winding gasket with inner ring for concave and convex flanges (Type B)
5.3 Dimensions of wound gaskets with locating rings for flat and raised face flanges
The dimensions of wound gaskets with locating rings for flat and raised face flanges shall be in accordance with Figure 3 and Table 6.
Table 6 Dimensions of ring wound gaskets for flat and protruding flanges (Type C)
5.4 Dimensions for flat and protruding flanges with inner ring and locating ring type wound gaskets
The dimensions of the wound gaskets with inner and locating rings for flat and protruding flanges shall be in accordance with the provisions of Figure 4 and Table 7.
6 Technical requirements
6.1 Materials
6.1.1 Metal strip
6.1.1.1 The metal strip shall be cold rolled steel strip with a thickness of 0.190 mm ± 0.040 mm, commonly used materials and codes are listed in Table 2, other materials than those listed in Table 2 are allowed according to the agreement between supply and demand. The surface of the strip shall be free from defects affecting its performance.
6.1.1.2 The chemical composition and mechanical properties of the stainless steel strip material shall conform to the provisions of GB/T 3280, and other materials shall conform to the provisions of the relevant standards.
6.1.2 Filled tape
6.1.2.1 The material code and recommended use temperature of the filler tape are shown in Table 3. other filler materials can be used according to the consultation between supply and demand, and meet the provisions of the relevant standards. The thickness and density of the filling material shall be determined by the manufacturer, but shall meet
6.5 Performance requirements.
6.1.2.2 The technical requirements of the flexible graphite tape for gaskets shall be in accordance with JB/T 7758.2.
6.1.2.3 The technical requirements for PTFE tapes for gaskets shall be in accordance with JB/T 6618.
6.1.2.4 Non-asbestos fibre tape for gaskets shall conform to the provisions of GB/T 27793.
6.1.2.5 Ceramic matrix composites for gaskets shall conform to the provisions of GB/T 3003.
6.1.2.6 Mica-based materials for gaskets should comply with the provisions of GB/T 5019.4.
6.1.2.7 High temperature resistant laminated silicate composites for gaskets should be in accordance with the provisions of the relevant international standards.
6.1.3 Inner ring and positioning ring
6.1.3.1 Unless otherwise agreed between the supplier and the customer, the inner ring material shall have a pre-corrosion and temperature resistance equal to or better than that of the metal strip.
6.1.3.2 Gaskets for flat (FF) or raised face (RF) flanges with PTFE filler tape shall be provided with an inner and locating ring,
6.1.3.3 Gaskets for flat (FF) or protruding (RF) flanges with a nominal pressure of PN 63 and above shall have an inner ring and a locating ring. 6.1.3.4 The material of the inner ring and locating ring shall conform to GB/T 3274, GB/T 3280, GB/T 2054 or related standards, and shall be treated against corrosion if carbon steel is used.
6.2 Process requirements
6.2.1 The gasket shall be made of prefabricated metal strip and non-metallic filler strip wound alternately, the metal strip and filler strip shall be tightly fitted, with a clear and even texture, without folds and gaps. The filler strip should be uniformly higher than the metal strip by approx. 0.2 mm and should not show the metal strip.
6.2.2 At least three layers of prefabricated metal tape without filler shall be used for the initial winding. The two initial windings should start with a minimum of three spot welds along the circumference at a maximum spacing of 75 mm. The final winding should also have a minimum of three layers of unfilled prefabricated metal tape. A minimum of three spot welds along the circumference and a final spot weld is the end weld.
6.2.3 The distance between the terminal weld and the previous weld shall not be greater than 35 mm. The terminal weld of the gasket with the locating ring shall be followed by a winding of not more than 4 turns of prefabricated metal tape to adjust the gap between the locating ring and the sealing element and to ensure that the locating ring does not fall off.
6.2.4 The inner ring and locating ring may be machined from the whole plate or from the splice, but the quality of the interface shall be guaranteed. The ring surface should be flat and the tolerance of its flatness should be less than 1%; the inner side of the positioning ring should have a groove of about 1.5 mm in depth to assemble the sealing element, and the groove or chamfer should be concentric with the inner and outer circles and symmetrical with the two end surfaces.
6.2.5 The gasket with inner ring can be made by winding directly on the outer circle of the inner ring, or by using special equipment to fix the inner ring and the sealing element tightly.
6.2.6 No mechanical processing or pre-pressing is permitted on the surface of the sealing element after it has been wound and formed.
6.3 Dimensional deviations
6.3.1 The dimensional measurement range of the gasket shall be in accordance with the provisions of Figure 1-1 and Figure 5.
6.3.2 The deviations of the inner and outer diameters of the sealing element, inner ring and positioning ring shall be in accordance with Table 8 and the deviations of the thickness shall be in accordance with Table 9.
Table 8 sealing elements and inner ring, positioning ring inside and outside diameter size deviation
6.4: Appearance quality
6.4.1 The surface of the sealing element shall not be allowed to have defects affecting the sealing performance.
6.4.2 The filling band on the surface of the sealing element shall be hooked above the metal band and shall not reveal the metal band.
6.4.3 Weld joints shall be on the symmetrical surface of the "V" shaped section of the metal belt, the distance between the weld joints shall comply with the requirements of 6.2.2 and 6.2.3, there shall be no defects such as unfused and overfused.
6.4.4 You should not have burrs, unevenness, rust spots and other defects on the surface of the inner ring and the positioning ring; the upper and lower sealing surface of the sealing element should be in the centre of the upper and lower surface of the inner ring and/or the positioning ring; the inner ring and the sealing element should be tightly fixed; the positioning ring and the sealing element should be allowed to slide in the circumferential direction, but should not fall off.
6.5 Performance requirements
6.5.1 The compression properties and test conditions of the gasket shall be in accordance with the provisions of Table 10.
7 Inspection methods
7.1 Quality of appearance
The appearance of the gasket shall be visually inspected.
7.2 Dimensional measurement
7.2.1 The thickness of the gasket (T, T;) shall be measured with a gauge with an accuracy of not less than 0.01 mm, using the arithmetic mean of the three points of the equal arc as the measurement result.
7.2.2 The diameter of the gasket (Dr, D:, Ds, D;) is measured with an accuracy of not less than 0.10 mm by means of a gauge with an arithmetic mean of two mutually perpendicular or more than two equal-arc measurements; if the actual size of the gasket diameter is greater than 1 000 mm, it can be measured with an accuracy of not less than 1.0 mm by means of a gauge.
7.2.3 Gaskets with basic and inner rings shall avoid welding joints when measuring the diameter of sealing elements.
8 Inspection rules
8.1 Inspection classification
The gasket inspection is divided into factory inspection and type inspection.
8.2 Factory inspection
8.2.1 The gasket shall be delivered only after it has been inspected by the manufacturer's quality inspection department in accordance with this document and after a quality certificate has been issued.
8.2.2 The factory inspection items for gaskets are dimensional deviation (6.3) and appearance quality (6.4).
8.2.3 During the factory inspection, the appearance quality shall be checked in accordance with 6.4. For gaskets of the same material combination and of the same construction type, 5 pieces of gaskets shall be taken from each batch of 100 pieces for dimensional inspection in accordance with 7.2; 3 pieces of gaskets shall be taken from each batch of 100 pieces, and the full inspection shall be carried out if the sampling quantity is not sufficient. If any one piece does not conform to the provisions of this document, the shim shall be retested by taking a quantity of shims with additional validity and if one piece still does not conform to the provisions of this document, the batch shall be fully inspected.
8.3 Type test
8.3.1 The gaskets shall be type tested for quality of appearance (6.4), deviation of goodness (6.3) and performance requirements (6.5).
8.3.2 For the type test, a batch of gaskets of the same material combination shall be tested by taking 3 pieces of each of the specimens specified in Table 10 and Table 11, or by making a sufficient number of specimens according to the same process if there are no specimens. If 1 piece of any item does not conform to the provisions of this document, double the number of shims shall be taken for re-testing of that item. If 1 piece still does not conform to the provisions of this document, the batch shall be judged to be unqualified or the type test shall fail.
9 Marking, labelling, order information, packaging and storage
9.1 Marking
The gasket shall be marked with the following elements.
Appendix A (informative) Customer order information
Bibliography
contents
1 Scope
2 Normative references
3 Terminology and definitions
4 Type and designation
5 Dimensions
6 Technical requirements
7 Inspection methods
8 Inspection rules
9 Marking, labelling, order information, packaging and storage
Appendix A (informative) Customer order information
Bibliography
