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1、INTERNATIONAL STANDARD INTERNATIONAL ORGANlZATlON FOR STANDARDIZATION.MElKYHAPOHA OPI-AHH3ALW.l II0 CTAHPIAPTH3AUHkI.ORGANISATION INTERNATIONALE DE NORMALlSATlON Fluid power systems and components - Multiple lip packing sets - Methods for measuring stack he.ights Transmissions h ydrauliques et pneum
2、atiques - Garnitures a l and both have the opportunity of ensuring understanding concerning what has been received and what has been supplied. Having these dimensions also provides designers with an understand- ing and a means for determining final installation conditions. 1 SCOPE AND FIELD OF APPLI
3、CATION This International Standard specifies methods for measur- ing sealing devices having more than one seal in the set. The sets are composed of homogeneous and/or fabric-reinforced fluid power lip sealing rings of various configurations such as V, Y, U and W, with or without adapters. This Inter
4、national Standard also specifies methods for measuring stack height of multiple lip packing sets in order that both supplier and user can determine that the sets are to an acceptable dimensional standard. It is not the intention of this International Standard to specify the dimensions for packing se
5、ts or their components, since such dimensions depend on the material being used, on the section and on the type of design. 2 REFERENCE IS0 5598, Fluid po wer - Vocabulary. ) 3 DEFINITIONS For definitions of terms used, see IS0 5598. 4 GENERAL 4.1 This International Standard describes three acceptabl
6、e methods for determining the stack height of a multiple lip packing set. Each method has distinct advantages and disad- vantages. However, there is a reasonable degree of corre- lation among these three methods, and users are advised to consult their suppliers to determine which of the three method
7、s the supplier is currently using. 4.2 It is recommended that the user consult the seal supplier to ascertain the method of measuring used and the applicable data, thus enabling the user to duplicate the supplier s method or correlate results if supplier and user methods are different. 1) In prepara
8、tioh. -,-,- 4.3 The following are some considerations that the user and the supplier should bear in mind in determining which method they propose to adopt. 4.3.1 Method 1 Unconfined (preferred) : recommended for diameters up to 200 mm (approximately) 4.4 Checking load 4.4.1 A checking load (PI is re
9、quired with each method. The amount of the checking load depends on the shape and material of the packing set and must be a value that nests the packing set components but does not deform them. The load must be agreed to by the supplier and user and can be determined as follows : 4.3.1.1 This method
10、 is very widely used by both suppliers and users throughout the world. This method, while usable for larger (over 200 mm) diameter sets by measuring a number of circumferential sections of the set, is the rec- ommended method for smaller (under 200 mm) diameter sets. 4.3.1.2 Essentially, only flat p
11、arallel plates and weights are required. See figure 1. 4.4.1.1 For method 1 and method 3, the load can be calculated from the mean diameter (D, of the packing set, the nominal radial cross-section of the packing set (C.S.) and a specific testing load (Pspec), i.e. P = (D,) (C.S.) v&J 4.4.1.2 For met
12、hod 2, the load can be calculated from the nominal radial cross-section (C.S.) of the packing set and a specific testing load (Pspec), i.e. 4.3.1.3 The user is cautioned that the resultant stack height under the checking load may not be the stack height in the seal housing. P = (C.S.) (Pspec) 4.4.2
13、A preload is required for method 3 and, if desired by the supplier and user, may be used with method 1 or 2. 4.3.2 Method 2 Confined at one point : recommended for diameters over 200 mm (approximately) 4.4.3 When calculating the checking loads, give consider- ation to components of the test setup wh
14、ich may contrib- ute to the applied load. 4.3.2.1 This method, while usable for smaller (under 200 mm) sets, is recommended for larger diameter sets. 5 METHOD FOR MEASURING STACK HEIGHT 4.3.2.2 The apparatus for this method is two parallel rods or pillars mounted on a rigid base plate, with the gap
15、between the pillars being adjustable. See figure 2. 5.1 Method 1 : Unconfined 4.3.2.3 The user is cautioned that the resultant stack height under the checking load may not be the stack height in the seal housing. 5.1.1 Centre the packing set on the lower plate of the measuring device. A typical devi
16、ce is shown in figure 1. 5.1.2 Apply a preload, if desired, to seat the packing. 4.3.3 Method 3 Confined I.D. and O.D. 5.1.3 Apply the checking load (see 4.4) and measure the stack height. 4.3.3.1 This method may be used for initial testing, and is normally correlated with method 1 or 2 for high qua
17、ntity production. 4.3.3.2 To use this method, a set of accurate I.D. (plug) and O.D. (ring) gauges and a follower ring are required for each size under consideration. The gauges are designed to duplicate the relevant seal housing, providing a stack height measurement which relates to that of the set
18、 in the seal housing. 4.3.3.3 Faulty readings may occur due to air entrapment or excessive friction. This risk can be minimized by pro- viding air ways in the gauges, by ensuring that the surface finishes of users and suppliers gauges are identical and by maintaining clean, undamaged and dry gauges.
19、 5.2 Method 2 : Confined at one point 5.2.1 Set pillars to nominal radial cross-section of seal housing. A typical device is shown in figure 2. 5.2.2 Insert the packing set, male adapter first, between the pillars of the device as shown in figure 3. 5.2.3 Ensure that the male adapter is in contact w
20、ith the base plate of the device. Apply the checking load (see 4.4) axially between the pillars. 5.2.4 Measure the depth of set between the pillars. The average of measurements at a number of equidistant points shall be taken. The number of measurements shall be agreed to by the supplier and user. 2
21、 -,-,- IS0 3939-1977 (E) Lower Checking load b plate I! i FIGURE 1 - Typical measuring device for method 1 and method 2 / Counterbalance Checking load - FIGURE 2 -Typical device for method 2 FIGURE 3 - Typical setup for method 2 3 IS0 3939-1977 (E) 5.3 Method 3 : Confined I.D. and O.D. 5.3.1 Insert
22、the packing set, female adapter first, into the O.D. ring. 5.3.2 Turn the assembly over. Insert the I.D. plug into the set (from the female adapter end). See example in figure 4. 5.3.3 Insert the follower ring. 5.3.4 Centre the unit on the base plate of the measuring device or fixture as used for me
23、thod 1 (see figure 1). Apply a preload to seat the packing. 5.3.5 Take care to ensure that there is no air entrapment between the seals, or abnormal friction between the packing and the gauges. These can cause faulty readings. 5.3.6 Remove the preload. Apply the checking load (see 4.4) and measure t
24、he stack height. 6 IDENTIFICATION STATEMENT (Reference to this International Standard) Use the following statement in test reports, catalogues and sales literature when electing to comply with this Inter- national Standard : “The method of measuring conforms to method . . . of IS0 3939, Fluid power systems and components - Multiple lip packing sets - Methods for measuring stack heights.” Load FIGURE 4 - Typical setup for method 3 4