NB/T 47038-2019Constant spring support and hanger (English PDF)

Foreword

This document was issued on 4 November 2019 by the National Energy Administration of the PRC and takes effect on 1 May 2020.

It is a NB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

It is classified under ICS 27.060, Chinese classification J 98.

It replaces NB/T 47038-2013, which is superseded.

This standard has been drafted in accordance with the rules given in GB/T 1.1-2009, Directives for standardization - Part 1: Structure and drafting of standards.

This standard replaces NB/T 47038-2013, Constant spring support and hanger.

Compared with NB/T 47038-2013, the main technical changes in this standard are the following.

Some values in Table 9 have been revised, as listed below.

Serial number 26, displacement 150: the original value 478 has been changed to 479.

Serial number 29, displacement 320: the original value 296 has been changed to 396.

Serial number 53, displacement 300: the original value 982 has been changed to 682.

Serial number 53, displacement 320: the original value 972 has been changed to 672.

Serial number 53, displacement 360: the original value 952 has been changed to 652.

Serial number 53, displacement 380: the original value 942 has been changed to 642.

Serial number 53, displacement 400: the original value 932 has been changed to 632.

Some values in Table 10 have been revised, as listed below.

Serial number 18, displacement 100: the original value 435 has been changed to 535.

Serial number 32, displacement 180: the original value 608 has been changed to 618.

In Table 12 the two duplicated rows for serial numbers 52 and 53 have been deleted.

In Table 17 the d0 value for serial numbers 19 to 23 has been changed from M10 to M16.

In Table 18 the data for serial number 62 at displacements 320, 340, 360, 380 and 400 have been revised, so that they are now identical with the data of serial number 63 at the same displacements.

Some values in Table 22 have been revised, as listed below.

Serial number 17, displacement 150: the original value 20 has been changed to 220.

Serial number 36, displacement 280: the original value 361 has been changed to 362.

Serial number 46, displacement 140: the original value 161 has been changed to 261.

Serial number 51, displacement 150: the original value 340 has been changed to 320.

Serial number 51, displacement 160: the original value 339 has been changed to 329.

In Table 26, serial number 44, displacement 380: the original value 88 has been changed to 883.

Some values in Table 27 have been revised, as listed below.

Serial number 36, displacement 280: the original value 361 has been changed to 362.

Serial number 51, displacement 160: the original value 339 has been changed to 329.

Some values in Table 28 have been revised, as listed below.

Serial number 16, displacement 300: the original value 975 has been changed to 974.

Serial number 30, displacement 320: the original value 1 389 has been changed to 1 384.

Serial number 38, displacement 140: the original value 1 581 has been changed to 1 586.

Some values in Table 29 have been revised, as listed below.

Serial number 36, displacement 280: the original value 361 has been changed to 362.

Serial number 46, displacement 140: the original value 161 has been changed to 261.

Serial number 51, displacement 160: the original value 339 has been changed to 329.

This standard was proposed by and is under the jurisdiction of the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).

Drafting organizations of this standard: Dalian Spring Co., Ltd.; Harbin Boiler Company Limited; Shanghai Boiler Works Co., Ltd.; Shanghai Power Equipment Research Institute Co., Ltd.

Main drafters of this standard: Zhang Fujun, Yu Yingying, Tong Qiang, Guo Jianming, Sha Zhaogen, Shi Huihui.

The previous editions of the standard replaced by this standard are: JB/T 8130.1-1995, JB/T 8130.1-1999 and NB/T 47038-2013.

A further previous edition replaced by this standard is GB 10181-1988.

Introduction

The constant spring support and hanger is a supporting and hanging device for thermal piping and heated equipment, and its standardized production has a history of several decades in China. It is widely used for the steam and water piping of thermal power plants, for the boiler proper of power stations, and in industries such as oil refining and chemical processing.

When the thermal piping and equipment suspended or supported by a constant spring support and hanger undergo thermal displacement, the device still provides a constant hanging force or supporting force. Load transfer and the additional stresses arising from it are therefore not produced in the piping and equipment, so that unfavourable load transfer and dangerous bending stresses caused by thermal deformation of the piping system are avoided and the normal operation of the piping and equipment is ensured.

After long-term practical application the operating results have proved to be good. During the implementation of NB/T 47038-2013 it was found that part of the data in the standard was erroneous, and that some installation dimensions produced according to those data were incorrect. The present revision was initiated in order to make the data accurate and consistent.

1 Scope

NB/T 47038-2019 standardises constant force spring supports and hangers, replacing the 2013 edition. Hot pipework moves as it heats: a steam line can rise or fall by tens of millimetres between cold and operating condition, and an ordinary spring hanger changes its load as it travels, pushing that variation back into the pipe and into the equipment nozzles at each end. A constant force unit uses a spring working through a cam or lever linkage so that the supporting force stays effectively unchanged across the whole travel, which is what lets a designer treat the support as a fixed load rather than a variable one. The standard fixes the basic structure of the units and the way a model is designated, the types available for hanging, bracing and supporting from below, and the complete series of load and displacement ratings with the dimensions of each size. It gives the materials for the spring, the casing and the load-bearing components, the permitted deviation of the supporting force across the travel, and the setting and locking of the unit at its cold position. Manufacture and inspection cover spring making and heat treatment, assembly, calibration against the nominal load, surface protection and marking, together with the type and routine tests. Selection, installation and adjustment on site close the document. It is used on power plant and process pipework in China.

1.1 This standard specifies the requirements for the terms and symbols, the structural types, the compilation of types, the series and dimensions, the manufacture and inspection, and the installation of constant spring supports and hangers.

1.2 This standard applies to constant spring supports and hangers with a displacement range of 50 mm to 400 mm and a load range of 123 N to 364 120 N (hereinafter referred to as supports and hangers).

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only the edition cited applies to this document.

For undated references, the latest edition (including all amendments) of the referenced document applies to this document.

GB/T 1805, Spring terminology.

GB/T 23934, Hot coiled helical compression springs - Technical specifications.

3 Terms and symbols

3.1 Terms. The terms and definitions given in GB/T 1805 and the following apply to this standard. For ease of use, some of the terms and definitions of GB/T 1805 are repeated below.

3.1.1 Constant support hanger: a support and hanger used to carry the dead weight load of piping, the carrying force of which does not vary with the vertical displacement of the piping at the supporting or hanging point, that is, a support and hanger whose load remains essentially constant.

3.1.2 Invariance (specified load deviation): the load deviation of a constant spring support and hanger caused by factors such as dynamic friction and manufacturing tolerances, compensated by a mechanical device or by an auxiliary spring.

3.1.3 Cold location: the positioning of the piping support and hanger assembly with reference to the adjacent structure when the piping is in the installed condition.

3.1.4 Hot location: the positioning of the piping support and hanger assembly with reference to the adjacent structure when the piping is in the hot condition or in the operating condition.

3.1.5 Normal load: the load corresponding to the size designation of the constant spring support and hanger; it may also be called the nameplate load.

3.1.6 Spring free height: the height of the spring when no load is acting on it. [GB/T 1805-2001, definition 3.17].

3.2 Symbols. The symbols used in this standard are the following.

H1 - installation height of the support and hanger in the cold location, for a support and hanger with single-direction displacement whose displacement is directed downwards, in mm.

H1S - installation height of the support and hanger in the cold location, for a support and hanger with single-direction displacement whose displacement is directed upwards, in mm.

H1XS - installation height of the support and hanger in the cold location, for a support and hanger with displacement in two directions, in mm.

T - the standard displacement value selected for the support and hanger; for a support and hanger with displacement in two directions it denotes the total displacement, in mm.

TX - the downward displacement value (selected displacement value) of a support and hanger having displacement in two directions, in mm.

TS - the upward displacement value (selected displacement value) of a support and hanger having displacement in two directions, in mm.

T(cal) - the maximum vertical displacement of the piping, that is, the calculated displacement value, in mm.

F - the actual measured load of the support and hanger when it is locked with the pin, in N.

Fb - the normal load of the support and hanger, that is, the selected standard load, in N.

FXmax - the maximum actual measured load of the support and hanger for displacement directed downwards, in N.

FSmin - the minimum actual measured load of the support and hanger for displacement directed upwards, in N.

X - the direction of displacement of the support and hanger is downwards.

S - the direction of displacement of the support and hanger is upwards.

4 Basic structure

The constant spring support and hanger consists essentially of a cylindrical helical spring, a fixed frame, a rotating frame together with the motion mechanism, an adjusting device and a spring casing.

The typical structure is shown in Figure 1, Schematic diagram of the flat type constant spring support and hanger; the parts identified in the figure are the root bolt, the fixed frame, the rotating frame, the tightening nut, the adjusting bolt, the fixed pin shaft, the spring casing, the displacement indicating plate, the main shaft, and the arrow indicating the displacement direction.

5 Method of model designation

The model designation of a standard constant spring support and hanger is made up of the following five parts.

First part: the type code of the support and hanger, expressed by one Chinese pinyin letter followed by one English letter.

Second part: the serial number of the support and hanger, or its load (the normal load may be omitted), expressed in Arabic numerals.

Third part: the selected standard displacement value of the support and hanger, expressed in Arabic numerals; for a support and hanger with displacement in two directions it expresses the selected standard total displacement.

Fourth part: the direction of displacement of the support and hanger, S meaning displacement directed upwards and X meaning displacement directed downwards; the form S equals xx, X equals xx denotes displacement in two directions.

Fifth part: the thread specification of the external hanger rod of the support and hanger, expressed by M followed by the nominal size and the pitch.

Example 1: PA35-150/18200X-M30 (or PA35-150X-M30) denotes a standard flat type A constant spring support and hanger of type PA, serial number 35, standard displacement 150 mm, normal load 18 200 N, with single-direction displacement directed downwards and external hanger rod thread M30.

Example 2: LB52-160/67208S-M56 by 4 (or LB52-160S-M56 by 4) denotes a standard vertical type B constant spring support and hanger of type LB, serial number 52, standard displacement 160 mm, normal load 67 208 N, with single-direction displacement directed upwards and external hanger rod thread M56 with a pitch of 4.

Example 3: PD38-170/19816 (S equals 70, X equals 100)-M36 [or PD38-170 (S equals 70, X equals 100)-M36] denotes a standard flat seat type D constant spring support and hanger of type PD, serial number 38, standard total displacement 170 mm of which the selected standard displacement is 70 mm upwards and 100 mm downwards, normal load 19 816 N, with external hanger rod thread M36.

6 Types

6.1 Basic types, load range and displacement range of constant spring supports and hangers. According to the difference in type, constant spring supports and hangers are divided into four kinds: flat type (PA, PB, PC, PE), flat seat type (PD), vertical type (LA, LB, LC, LE) and vertical seat type (ZA, ZB). The serial number range, the supporting and hanging arrangement, and the load and displacement ranges of the supports and hangers shall comply with Table 1.

Table 1, type PA (flat type): the top plate of the fixed frame is connected to the supporting member by means of two threaded hanger rods, and the piping and equipment below are suspended from it.

Table 1, type PB (flat type): the top plate of the fixed frame is connected to the supporting member by means of a single threaded hanger rod, and the piping and equipment below are suspended from it.

Table 1, type PC (flat type): the top plate of the fixed frame is connected to the supporting member by means of a single-hole lug plate, and the piping and equipment below are suspended from it.

Table 1, type PE (flat type): the top plate of the fixed frame is connected to the supporting member by means of a double-hole lug plate, and the piping and equipment below are suspended from it.

Table 1, flat types PA, PB, PC and PE: serial number range 1 to 78; load range 123 N to 364 120 N; displacement range 50 mm to 400 mm; for details see Table 3.

Table 1, type PD (flat seat type): the bottom plate of the fixed frame is mounted on the supporting member, and the piping and equipment below are suspended from it.

Table 1, type PD: serial number range 19 to 78; load range 1 597 N to 364 120 N; displacement range 60 mm to 400 mm; for details see Table 4.

Table 1, type LA (vertical type): the top plate of the fixed frame is connected to the supporting and hanging member by means of two threaded hanger rods, and the piping and equipment below are suspended from it.

Table 1, type LB (vertical type): the top plate of the fixed frame is connected to the supporting and hanging member by means of a single threaded hanger rod, and the piping and equipment below are suspended from it.

Table 1, type LC (vertical type): the top plate of the fixed frame is connected to the supporting and hanging member by means of a single-hole lug plate, and the piping and equipment below are suspended from it.

Table 1, type LE (vertical type): the top plate of the fixed frame is connected to the supporting member by means of a double-hole lug plate, and the piping and equipment below are suspended from it.

Table 1, vertical types LA, LB, LC and LE: serial number range 1 to 74; load range 123 N to 29 936 N; displacement range 50 mm to 400 mm; for details see Table 15.

Table 1, type ZA (vertical seat type): the bottom plate of the spring casing is mounted on the supporting member, and the piping and equipment below are suspended from it.

Table 1, type ZA: serial number range 14 to 55; load range 1 098 N to 83 133 N; displacement range 80 mm to 400 mm; for details see Table 23.

Table 1, type ZB (vertical seat type): the bottom plate of the spring casing is mounted on the supporting member, and it supports the piping and equipment above it.

Table 1, type ZB: serial number range 14 to 55; load range 1 098 N to 99 754 N; displacement range 60 mm to 400 mm; for details see Table 24.

6.2 Typical supporting and hanging examples of constant spring supports and hangers. For typical supporting and hanging examples of constant spring supports and hangers see Annex A.

7 Load-displacement series and basic dimensions

7.1 The schematic diagram, the load-displacement series, the main overall dimensions and the connection dimensions of each type of support and hanger shall be looked up as shown in Table 2.

Table 2, type PA (flat type): schematic diagram Figure 2; load-displacement series Table 3; main overall dimensions Table 6; H1 values Table 9; Q values Table 13.

Table 2, type PB (flat type): schematic diagram Figure 4; load-displacement series Table 3; main overall dimensions Table 7; H1 values Table 9; Q values Table 12.

Table 2, type PC (flat type): schematic diagram Figure 5; load-displacement series Table 3; main overall dimensions Table 7; H1 values Table 10; Q values Table 12.

Table 2, type PE (flat type): schematic diagram Figure 3; load-displacement series Table 3; main overall dimensions Table 6; H1 values Table 10; Q values Table 13.

Table 2, type PD (flat seat type): schematic diagram Figure 6; load-displacement series Table 4; main overall dimensions Table 8; H1 values Table 11; Q values Table 14.

Table 2, type LA (vertical type): schematic diagram Figure 7; load-displacement series Table 15; main overall dimensions Table 16; H1 values Table 18; Q values Table 20; V values Table 22.

Table 2, type LB (vertical type): schematic diagram Figure 9; load-displacement series Table 15; main overall dimensions Table 17; H1 values Table 18; Q values Table 21; V values Table 22.

Table 2, type LC (vertical type): schematic diagram Figure 10; load-displacement series Table 15; main overall dimensions Table 17; H1 values Table 19; Q values Table 21; V values Table 22.

Table 2, type LE (vertical type): schematic diagram Figure 8; load-displacement series Table 15; main overall dimensions Table 16; H1 values Table 19; Q values Table 20; V values Table 22.

Table 2, type ZA (vertical seat type): schematic diagram Figure 11; load-displacement series Table 23; main overall dimensions Table 25; H1 values Table 26; V values Table 27.

Table 2, type ZB (vertical seat type): schematic diagram Figure 12; load-displacement series Table 24; main overall dimensions Table 25; H1 values Table 28; V values Table 29.

7.2 For the K values of each type of support and hanger see Table 5.

7.3 For the weights of each type of support and hanger see Table 30.

7.4 For the main axial dimensions of the tightening nut of each type of support and hanger see Table 31, and for the outline schematic diagram see Figure 13. When the supports and hangers leave the works, the thread projection of the tightening nut is 20 mm in all cases (see the schematic diagrams of the various kinds of supports and hangers).

7.5 For the selection of the root thread specification and of the hanger rod thread specification of each type of support and hanger see Table 32.

7.6 The installation height in the cold location of each type of support and hanger shall comply with the following provisions.

7.6 a) Installation height of supports and hangers having displacement in one direction. The values given in the H1 value tables of the various types of support and hanger are in all cases the installation heights in the cold location of a support and hanger having single-direction displacement whose displacement is directed downwards; the value of the installation height in the cold location when the displacement is directed upwards is H1S, and H1S is calculated by formulas (1) and (2).

Formula (1), for flat type, vertical type and flat seat type supports and hangers: H1S equals H1 plus T.

Formula (2), for vertical seat type supports and hangers: H1S equals H1 minus T.

In formulas (1) and (2): H1S is the installation height in the cold location of a support and hanger having single-direction displacement whose displacement is directed upwards, in mm.

In formulas (1) and (2): H1 is the installation height in the cold location of a support and hanger having single-direction displacement whose displacement is directed downwards, in mm.

In formulas (1) and (2): T is the standard displacement value selected for the support and hanger; for a support and hanger with displacement in two directions it denotes the total displacement, in mm.

7.6 b) Installation height of supports and hangers having displacement in two directions. For a support and hanger having displacement in two directions, the value of the installation height in the cold location is H1XS, and H1XS is calculated by formulas (3) and (4).

Formula (3), for flat type, vertical type and flat seat type supports and hangers: H1XS equals H1 plus TS.

Formula (4), for vertical seat type supports and hangers: H1XS equals H1 minus TS.

In formulas (3) and (4): H1XS is the installation height in the cold location of a support and hanger having displacement in two directions, in mm.

In formulas (3) and (4): TS is the upward displacement value (selected displacement value) of a support and hanger having displacement in two directions, in mm.

For a support and hanger of any type having displacement in two directions, the displacement quantities always follow formula (5): T equals TX plus TS, where TX is the downward displacement value (selected displacement value) of a support and hanger having displacement in two directions, in mm.

Table 3 gives the load-displacement series of the flat type (PA, PB, PC, PE) constant spring supports and hangers. The rows of the table are the serial numbers of the supports and hangers and the columns are the standard displacement values in mm, namely 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380 and 400; the values in the body of the table are the normal loads in N.

Table 3, serial number 1: normal load 493 N at 50 mm displacement, 411 N at 60 mm, 352 N at 70 mm, 308 N at 80 mm, 273 N at 90 mm, 247 N at 100 mm, 224 N at 110 mm, 206 N at 120 mm, 189 N at 130 mm, 176 N at 140 mm, 165 N at 150 mm, 154 N at 160 mm, 145 N at 170 mm, 137 N at 180 mm, 129 N at 190 mm and 123 N at 200 mm.

Table 3, serial number 2: normal load 695 N at 50 mm displacement, 579 N at 60 mm, 497 N at 70 mm, 434 N at 80 mm, 386 N at 90 mm, 348 N at 100 mm, 316 N at 110 mm, 290 N at 120 mm, 268 N at 130 mm, 248 N at 140 mm, 231 N at 150 mm, 218 N at 160 mm, 205 N at 170 mm, 193 N at 180 mm, 183 N at 190 mm and 173 N at 200 mm.

Table 3, serial number 3: normal load 919 N at 50 mm displacement, 766 N at 60 mm, 657 N at 70 mm, 575 N at 80 mm, 511 N at 90 mm, 460 N at 100 mm, 418 N at 110 mm, 383 N at 120 mm, 354 N at 130 mm, 328 N at 140 mm, 307 N at 150 mm, 287 N at 160 mm, 270 N at 170 mm, 256 N at 180 mm, 242 N at 190 mm and 230 N at 200 mm.

Table 3, serial number 4: normal load 1 012 N at 50 mm displacement, 844 N at 60 mm, 723 N at 70 mm, 633 N at 80 mm, 563 N at 90 mm, 507 N at 100 mm, 461 N at 110 mm, 422 N at 120 mm, 389 N at 130 mm, 362 N at 140 mm, 337 N at 150 mm, 317 N at 160 mm, 298 N at 170 mm, 281 N at 180 mm, 267 N at 190 mm and 253 N at 200 mm.

Table 3, serial number 5: normal load 1 088 N at 50 mm displacement, 911 N at 60 mm, 774 N at 70 mm, 676 N at 80 mm, 608 N at 90 mm, 549 N at 100 mm, 500 N at 110 mm, 451 N at 120 mm, 421 N at 130 mm, 392 N at 140 mm, 363 N at 150 mm, 343 N at 160 mm, 323 N at 170 mm, 304 N at 180 mm, 284 N at 190 mm and 274 N at 200 mm.

Table 3, serial number 6: normal load 1 421 N at 50 mm displacement, 1 186 N at 60 mm, 1 019 N at 70 mm, 892 N at 80 mm, 794 N at 90 mm, 706 N at 100 mm, 647 N at 110 mm, 588 N at 120 mm, 549 N at 130 mm, 510 N at 140 mm, 470 N at 150 mm, 441 N at 160 mm, 421 N at 170 mm, 392 N at 180 mm, 372 N at 190 mm and 353 N at 200 mm.

Table 3 continues in the same manner for the remaining serial numbers; as the serial number increases the range of available displacements moves towards the larger values, so that the highest serial numbers of the flat type series cover displacements from 90 mm up to 400 mm, the whole series spanning normal loads from 123 N up to 364 120 N.