DOCSLIB.ORG

Safety Valve for Fuel Injection Apparatus

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Safety Valve for Fuel Injection Apparatus Europaisches Patentamt European Patent Office © Publication number: 0 466 081 A1 Office europeen des brevets EUROPEAN PATENT APPLICATION © Application number: 91111358.7 int. Ci.5; F02M 59/46, F02M 63/00 @ Date of filing: 08.07.91 © Priority: 09.07.90 JP 182410/90 © Applicant: NIPPONDENSO CO., LTD. 1-1, Showa-cho @ Date of publication of application: Kariya-shi Aichi-ken(JP) 15.01.92 Bulletin 92/03 @ Inventor: Kariya, Yasuhiro © Designated Contracting States: Sharuman Hausu 203, 34-11, Higashitoyoda DE FR GB IT 2-chome Hino-shi(JP) © Representative: Tiedtke, Harro, Dipl.-lng. et al Patentanwaltsburo Tiedtke-Buhling-Kinne- Grupe-Pellmann-Grams Bavariaring 4 Postfach 20 24 03 W-8000 Munchen 2(DE) © Safety valve for fuel injection apparatus. © A safety valve (3) provided in a fuel injection to maintain a pressure for pressing the valve ele- apparatus including an accumulator (1) in which fuel ment (36) in a valve-opening direction, wherein the is accumulated, comprises: a housing (30) having an high-pressure fuel from the inside passage (31) is inside passage (31) for introducing the high-pressure introduced into the fuel chamber (39) when the valve fuel of the accumulator (1) into the inside of the body (37) of the valve element (36) is separated housing (30) and a seat face (32) formed at a portion from the seat face (32). With this safety valve (3), of the inside passage (31); a valve element (36) the high-pressure fuel of the accumulator (1) is intro- provided movably within the housing (30) and includ- duced into the fuel chamber (39) in order to press ing a valve body (37) to open/close the seat face the valve element (36) in the valve-opening direction (32); an elastic member (38) for pressing and biasing so that the valve element (36) will be rapidly opened, the valve element (36) in a closing direction; and a with the result that the fuel pressure in the accu- fuel chamber (39) defined between the inner surface mulator (1) can recover a predetermined value in- of the housing (30) and the valve element (36) so as stantaneously. < F I G. 00 o CO CO 36 Rank Xerox (UK) Business Services 1 EP 0 466 081 A1 2 BACKGROUND OF THE INVENTION Therefore, the present invention is intended to provide a safety valve of a fuel injection apparatus Field of the Invention which can obtain a property of a large flow rate after the valve is opened and which can constantly The present invention relates to a safety valve 5 maintain the pressure in an accumulator to be not of an accumulator in a fuel injection apparatus of a higher than a critical pressure. diesel engine for injecting high-pressure fuel accu- It is a further object of the invention to provide mulated in the accumulator by means of an injector a safety valve which enables the fail-safe system to of an electronic control type provided in each cyl- function favorably at the time of a trouble by regu- inder. io lating a clearance between the inner peripheral surface of a small-diameter section and the outer Description of the Prior Art peripheral surface of a valve element so as to set the increased fuel pressure in the accumulator to a There has been conventionally known a fuel predetermined value. injection apparatus, as disclosed in Japanese Pat- 75 Another object of the invention is to provide a ent Unexamined Publication No. 59-165858, which safety valve which enables the fuel pressure in the is arranged in such a manner that high-pressure accumulator to recover a predetermined value in- fuel is accumulated in an accumulator called a stantaneously by opening the valve rapidly once it common rail by a high-pressure supply pump, and reaches a valve-opening pressure. the high-pressure fuel of the accumulator is in- 20 jected by an injector of an electronic control type BRIEF DESCRIPTION OF THE DRAWINGS provided in each cylinder. This fuel injection apparatus is provided with a Figs. 1 to 4 relate to one embodiment of a safety valve which is opened for releasing the fuel safety valve according to the present invention: when a pressure in the accumulator exceeds a 25 Fig. 1 is a cross-sectional view showing the predetermined value. whole structure of the safety valve; As shown in Fig. 5, the structure of the conven- Fig. 2 is a schematic view showing the entire tional safety valve is such that a tapered seat face system of a fuel injection apparatus including 32 which is an opening portion of a passage 31 in the safety valve applied to the present embodi- communication with the accumulator is 30 ment; opened/closed by a ball valve 37, and that when Fig. 3 is an enlarged fragmentary view of a the fuel pressure in the accumulator exceeds a portion enclosed by a circle line III in Fig. 1; and biasing force of a spring 38 which presses and Fig. 4 is an operational characteristic graph of biases the ball valve 37 in a valve-closing direction, the safety valve. the ball valve 37 is opened to release the fuel of 35 Figs. 5 and 6 relate to a prior art concerning the the accumulator to the low pressure side, thereby present invention: suppressing an increase of pressure in the accu- Fig. 5 is a cross-sectional view showing the mulator. whole structure of the conventional safety valve; With this structure, however, an area of an and opening after the ball valve 37 is opened is insuffi- 40 Fig. 6 is an operational characteristic graph of cient. Consequently, even after the fuel has been the safety valve. once released through the opened valve, there is a risk that the pressure in the accumulator is in- DETAILED DESCRIPTION OF THE PREFERRED creased to exceed a valve-opening pressure of the EMBODIMENT ball valve 37 when the fuel is pressurized and 45 delivered again. Particularly when the fuel of a One embodiment of the present invention will maximum flow rate Qmax is pressurized and deliv- be hereinafter described with reference to the at- ered from the high-pressure supply pump to the tached drawings. accumulator, there is a risk, as shown in Fig. 6, that Referring to Fig. 2, fuel supplied from a fuel the fuel pressure is increased to exceed not only 50 tank (not shown) is pressurized and delivered the valve-opening pressure Po but also a critical through a conduit via a delivery valve by means of internal pressure PE of an accumulation piping. a high-pressure supply pump 2 such as a priming pump, and accumulated in an accumulation cham- SUMMARY OF THE INVENTION ber of an accumulator 1 which is called a common 55 rail. It is an object of the present invention to pro- The high-pressure fuel accumulated in the ac- vide a fuel injection apparatus capable of prevent- cumulation chamber of the accumulator 1 is in- ing an abnormal increase of a fuel pressure. jected into an internal combustion engine through 2 3 EP 0 466 081 A1 4 an opened nozzle hole when a nozzle needle hav- 33, and when the pressure PR is set to a minimum ing a distal-end portion to open/close the nozzle value which the pressure in the accumulator 1 is hole is biased in a valve-opening direction by a required to have for operating the engine, the fail- pressure of the fuel supplied through a check valve safe and limp-home system can be functioned fa- and a passage in an injector of an electronic con- 5 vorably at the time of a trouble. trol type (not shown) provided in each cylinder. According to the present invention, as de- At an end portion of the accumulator 1 , there is scribed heretofore, when the valve body of the provided a safety valve 3 for controlling the fuel valve element is separated from the seat face, the pressure in the accumulator 1 so as to prevent it high-pressure fuel introduced from the inside pas- from exceeding a critical value. io sage flows into the fuel chamber, and the pressure As shown in Figs. 1 and 3, the safety valve 3 in this fuel chamber presses the valve element in comprises: a housing 30 which includes an inside the valve-opening direction so that the valve ele- passage 31 in communication with the accumulator ment will be rapidly opened, with the result that the 1, a tapered seat face 32 formed at an opening fuel pressure in the accumulator can recover a portion of the inside passage 31 , a small-diameter is predetermined value instantaneously. section 33, a spring chamber 34 and a low-pres- A safety valve provided in a fuel injection ap- sure passage 35 in communication with a fuel tank paratus including an accumulator in which fuel is 4 on the low pressure side of the safety valve; a accumulated, comprises: a housing having an in- valve element 36 provided movably within the side passage for introducing the high-pressure fuel housing 30, with a ball valve 37 to open/close the 20 of the accumulator into the inside of the housing seat face 32 being fixed on this valve element; and and a seat face formed at a portion of the inside a spring 38 which presses and biases the valve passage; a valve element provided movably within element 36 in a valve-closing direction. The valve the housing and including a valve body to element 36 is closely fitted in the small-diameter open/close the seat face; an elastic member for section 33 of the housing 30, and a fuel chamber 25 pressing and biasing the valve element in a closing 39 which maintains a pressure for pressing the direction; and a fuel chamber defined between the valve element 36 in the valve-opening direction is inner surface of the housing and the valve element defined between the valve element 36 and the end so as to maintain a pressure for pressing the valve surface of the small-diameter section 33.
Load more

Recommended publications
  • Establishing Relieving Capacities
    Establishing Relieving Capacities Prepared for Chief’s meeting October 9, 2019 By Joseph F. Ball, P. E. Overview of Session • Review of Section IV Pressure Relief Capacity Requirements • ASME Requirements • NBIC Installation Requirements • Establishment of Relieving Capacity for Section IV Pressure Relief Valves Section IV Capacity Requirements The Basics: Overpressure protection requirements are defined by boiler manufacturer. Nameplate shall include: (HG-530.1(a)(3)) Safety or safety relief valve capacity (minimum) as determined according to HG-400.1(d) and HG-400.2(e) Heating area must be marked Section IV Capacity Requirements The Basics: Same for cast iron or aluminum (HG-530.2(c)(3)) – depends upon number of sections Section IV Capacity Requirements The Basics: Modular Boilers • Each module has its own nameplate with capacity required for that module • Aggregate capacity (and heating area) is applied to a single nameplate for the combined unit Section IV Capacity Requirements The Basics: HG-400.1 (d) The minimum valve capacity in pounds per hour shall be determined by dividing the maximum Btu/hr (kW) output at the boiler nozzle obtained by the firing of any fuel for which the unit is installed by 1,000 (0.646). In every case, the requirement of (e) shall be met. (e) The safety valve capacity for each steam boiler shall be such that with the fuel burning equipment installed, and operated at maximum capacity, the pressure cannot rise more than 5 psi (35 kPa) above the maximum allowable working pressure. Section IV Capacity Requirements The Basics: HG-400.2 (e) The required steam-relieving capacity, in pounds per hour (kg/hr), of the pressure-relieving device or devices on a boiler shall be determined by dividing the maximum output in Btu/hr (kW) at the boiler nozzle obtained by the firing of any fuel for which the unit is installed by 1,000 (0.646).
    [Show full text]
  • Steamboating Guide Edition 2 2010
    Steamboating SampleGuide Pages Second Edition Steamboating Guide Edition 2 2010 Edited by Roger Calvert and Rob van Es The contributors and editors of this publication have made every effort to ensure the accuracy and relevance of the data presented and the validity and appropriateness of the recommendations made. It is, however, ultimately the responsibility of the owner of a boat to check the data and take the final decisions, in the context of the proposed design. If necessary, appropriate professional advice should be sought. Neither the contributors, the editors, nor the SBA can accept responsibility for any direct or indirect consequences arising from the use of the data or from following the recommendationsSample of this publication. Pages Copying of parts or the whole of this document by members of the SBA is permitted, subject to the terms published on the SBA web site. Otherwise, copying is not permitted without the permission of the SBA, except as allowed under copyright law. Table of Contents Preface Section A – Introduction 1 Hulls 1-1 2 Boiler Types 2-1 3 Engine Types 3-1 4 Fuels 4-1 Section B – Steamboat Operations 5 Boiler Fittings 5-1 6 Steam Plant Installation 6-1 7 Boiler Operation and Maintenance 7-1 8 Steam Ancillaries 8-1 9 Boat Handling Advice 9-1 10 Boiler Inspection and Testing 10-1 11 Trailers and Towing 11-1 Section C – Technical 12 Propulsion 12-1 13 Valve Setting 13-1 14 Data and Performance 14-1 15 Boiler Design Considerations 15-1 16 Workshop Techniques 16-1 Glossary 17-1 Index 18-1 Sample Pages Preface The aims and objects of the Steam Boat Association are: (i) To foster and encourage steam boating and the building, development, preservation and restoration of steam boats and steam machinery, by all possible means.
    [Show full text]
  • Westinghouse Technology 7.1 Main and Auxiliary Steam Systems
    Westinghouse Technology Systems Manual Section 7.1 Main and Auxiliary Steam Systems TABLE OF CONTENTS 7.1MAIN AND AUXILIARY STEAM SYSTEMS ................................................... 7.1-1 7.1.1 Introduction .......................................................................................... 7.1-1 7.1.2 Main Steam System Description ......................................................... 7.1-1 7.1.2.1 Safety Considerations ............................................................ 7.1-2 7.1.2.2 Accident Considerations ........................................................ 7.1-3 7.1.3 Main Steam System Component Descriptions .................................... 7.1-4 7.1.3.1 Flow Restrictors ..................................................................... 7.1-4 7.1.3.2 Main Steam Instrumentation .................................................. 7.1-4 7.1.3.3 Power-Operated Relief Valves ............................................... 7.1-5 7.1.3.4 Steam Generator Safety Valves ............................................ 7.1-6 7.1.3.5 AFW Pump Steam Supplies .................................................. 7.1-6 7.1.3.6 High Pressure Drains ............................................................. 7.1-6 7.1.3.7 Main Steam Isolation Valves .................................................. 7.1-7 7.1.3.8 Main Steam Check Valves ..................................................... 7.1-8 7.1.3.9 MSIV Bypass Valves .............................................................. 7.1-8 7.1.4 Auxiliary Steam System
    [Show full text]
  • Hydraulic Valve Remote Control System
    HYDRAULIC VALVE REMOTE CONTROL SYSTEM OVERVIEW Nordic Flow Control’s compact design for our Hydraulic Valve Remote Control Systems does not compromise on power. Our systems operate at a higher torque level even with our smaller actuators. Submerged applications are available, and maintenance is possible even during operation. By having a hand pump in a deck box with solenoid valves, manual operations are now possible. Our Hydraulic Valve Remote Control Systems are tried and tested in the harshest conditions. The system consists of the hydraulic actuator, a power unit, solenoid valve cabinet, and the control station with operating system. Our actuators and control systems are able to match and operate valves with no limitations. BENEFITS • Able to operate bigger size valves with smaller actuators • Able to use for submerged applications • Cost efficient • Reliable • Able to operate at hazardous areas • Simplicity of design and control Nordic Flow Control Valve Remote Control Systems 1 COMPONENTS ACTUATORS Nordic Flow Control’s actuators are manufactured using sophisticated machinery in our own production plant. They convert hydraulic energy directly into a mechanical rotating movement by using the rack and pinion principle, elimi- nating cost from intensive servicing, maintenance and the sensitivity of transmission elements. Our actuators are created for durability, performance and cost effectiveness. Our new NRA series actuators are now more compact and provide higher torque at even smaller sizes. They have a longer life span, with higher efficiency. Polymer bearings for smaller actuators and ball bearings for bigger actuators are used to reduce friction between the parts. Mounting is according to ISO5211 standards, but can be customised to meet other requirements.
    [Show full text]
  • NBIC Pressure Relief Device (PRD) Inspection Guide
    NBIC Pressure Relief Device (PRD) Inspection Guide This guide provides a basis for NBIC Inspectors use in reviewing Pressure Relief Devices (PRD’s) for compliance with the National Board Inspection Code (NBIC). It is only intended to provide general guidance, and must be used in conjunction with NBIC, Part 2 for specific details of inspection. 1. Description and Overview Pressure relief devices are used to provide a means of venting excess pressure which could rupture a boiler or pressure vessel. A pressure relief device is the last line of defense for safety. If all other safety devices or operating controls fail, the pressure relief device must be capable of venting excess pressure. 2. Types of Devices There are many types of pressure relief devices available for use in the boiler and pressure vessel industry. This inspector guide will address the most common devices found on boilers and pressure vessels. Virtually all jurisdictions require a pressure relief device to be manufactured and certified in accordance with the ASME Code in addition to being capacity certified by the National Board. The most common types of pressure relief devices are: Pressure Relief Valve – A pressure relief device designed for emergency or abnormal over pressure conditions and designed to reclose after the pressure has been reduced. Safety Valve – This device is typically used for steam or vapor service. It operates automatically with a full-opening pop action and recloses when the pressure drops to a value consistent with the blowdown requirements prescribed by the applicable governing code or standard. Relief Valve – This device is typically used for liquid service.
    [Show full text]
  • BASIS SAFETY CONTROLS for HOT WATER and LOW-PRESSURE STEAM BOILERS By: Tom Vana, Factory Representative, Mcdonnell & Miller, Inc
    Service Application Manual SAM Chapter 630-36 Section 20 BASIS SAFETY CONTROLS FOR HOT WATER AND LOW-PRESSURE STEAM BOILERS By: Tom Vana, Factory Representative, McDonnell & Miller, Inc. HOT WATER SPACE HEATING BOILERS SAFTETY RELIEF VALVES Good engineering tells us that every hot water boiler must have a safety relief valve that will keep the pressure at or below the maximum allowable working pressure of the boiler. But until recently the methods of accomplishing this objective were not clearly understood. Figure 70F51A shows one method of attempting to provide protection against over-pressure which is unsafe for these reasons: 1. The relief valve does not comply with the ASME Boiler code requirements. 2. Its capacity is unknown. 3. It is installed in the wrong location. 4. It can inadvertently be isolated from the boiler due to lime or scale build-up in boiler feed line. 5. The function of a relief valve has nothing in common with a pressure reducing type fill valve. A combination of the two units is based on price consideration—not performance. The first basic step in providing correct safety control for a hot water boiler is to make sure that an ASME relief valve is installed. The ASME Code states: “Every hot water heating boiler shall have at least one officially rated pressure relief valve set to relieve at or below the maximum allowable working pressure of the boiler… Relief valve shall be connected to the Copyright © 1966, 2009, By Refrigeration Service Engineers Society. -1- top of boilers with the spindle vertical if possible…. No shutoff of any description shall be placed between the relief valve and the boiler, nor on the discharge pipe between such valve and the atmosphere.” Figure 70F51B shows the correct and safe installation of the relief valve.
    [Show full text]
  • Hackworth Family Archive
    Hackworth Family Archive A cataloguing project made possible by the National Cataloguing Grants Programme for Archives Science Museum Group 1 Description of Entire Archive: HACK (fonds level description) Title Hackworth Family Archive Fonds reference code GB 0756 HACK Dates 1810’s-1980’s Extent & Medium of the unit of the 1036 letters with accompanying letters and associated documents, 151 pieces of printed material and printed images, unit of description 13 volumes, 6 drawings, 4 large items Name of creator s Hackworth Family Administrative/Biographical Hackworth, Timothy (b 1786 – d 1850), Railway Engineer was an early railway pioneer who worked for the Stockton History and Darlington Railway Company and had his own engineering works Soho Works, in Shildon, County Durham. He married and had eight children and was a converted Wesleyan Methodist. He manufactured and designed locomotives and other engines and worked with other significant railway individuals of the time, for example George and Robert Stephenson. He was responsible for manufacturing the first locomotive for Russia and British North America. It has been debated historically up to the present day whether Hackworth gained enough recognition for his work. Proponents of Hackworth have suggested that he invented of the ‘blast pipe’ which led to the success of locomotives over other forms of rail transport. His sons other relatives went on to be engineers. His eldest son, John Wesley Hackworth did a lot of work to promote his fathers memory after he died. His daughters, friends, grandchildren, great-grandchildren and ancestors to this day have worked to try and gain him a prominent place in railway history.
    [Show full text]
  • Pentair Pressure Relief Valve Engineering Handbook Anderson Greenwood, Crosby and Varec Products
    Pentair Pressure Relief Valve Engineering Handbook Anderson Greenwood, Crosby and Varec Products VALVES & CONTROLS Pentair Pressure Relief Valve Engineering Handbook Forward Technical Publication No. TP-V300 Copyright © 2012 Pentair Valves & Controls. All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without written permission. Pentair Valves & Controls (PVC) provides the information herein in good faith but makes no representation as to its comprehensiveness or accuracy. Individuals using this information in this publication must exercise their independent judgment in evaluating product selection and determining product appropriateness for their particular purpose and system requirements. PVC makes no representations or warranties, either express or implied, including without limitation any warranties of merchantability or fitness for a particular purpose with respect to the information set forth herein or the product(s) to which the information refers. Accordingly, PVC will not be responsible for damages (of any kind or nature, including incidental, direct, indirect, or consequential damages) resulting from the use of or reliance upon this information. Pentair reserves the right to change product designs and specifications without notice. All registered trademarks are the property of their respective owners. Printed in the USA. PVCMC-0296-US-1203 rev 12-2012 Pentair Pressure Relief Valve Engineering Handbook Contents Technical Publication No. TP-V300 Table of Contents Chapter 1 – Introduction 1.1 Chapter 2 – Terminology 2.1 I. General 2.1 II. Types of Devices 2.1 III. Parts of Pressure Relief Devices 2.1 IV. Dimensional Characteristics – Pressure Relief Valves 2.2 V.
    [Show full text]
  • SAFETY VALVES BASIC KNOWLEDGE Protection Against Overpressure
    SAFETY VALVES BASIC KNOWLEDGE Protection against overpressure. The primary purpose of a safety valve is the pro- tection of life, property and environment. A safe- ty valve is designed to open and relieve excess pressure from vessels or equipment and to reclose and prevent the further release of fluid after normal CONTENTS conditions have been restored. REASONS FOR P. 04 1. EXCESS PRESSURE IN A VESSEL SPRING LOADED P. 06 2. SAFETY VALVES PILOT-OPERATED P. 08 3. SAFETY VALVES Pressure Relief Devices Reclosing Devices ENSURING Non-reclosing Devices PLANT SAFETY Rupture Disc Direct-load Controlled Pin-actuated Device Controlled Safety Pressure Relief System Spring Weight Loading Principle loaded loaded Pilot-Operated Safety Valve Relief Safety Safety Snap-acting Modulating Valve* Valve* Relief Function Valve* *acc. to ASME A safety valve is a safety device and in many cases the last line of defence. It is important to ensure that the safety valve is capable to operate at all times and under all circumstances. A safety valve is not a process valve or pressure regulator and should not be misused as such. It should have to operate for one purpose only: overpressure protection. 1. REASONS FOR EXCESS PRESSURE IN A VESSEL There is a number of reasons why the pressure in a Each of the above listed events may occur individ- vessel or system can exceed a predetermined lim- ually and separately from the other. They may also it. API Standard 521/ISO 23251 Sect. 4 provides take place simultaneously. Each cause of over- a detailed guideline about causes of overpressure.
    [Show full text]
  • You Are Judged by the Company You Keep!
    You are judged by the company you keep! Having an FPTI™ training system in your laboratory will tell its own story about the quality of your hydraulics training program. Why you should choose FPTI™ as your hydraulics education partner! SAFETY-BASED TRAINING We are the only hydraulics training company that makes safety the cornerstone of everything we develop. You will feel confident knowing that students who graduate from your training courses will have the knowledge to work safely with hydraulics, and moreover, be able to cultivate hydraulic safety wherever they go. In keeping with our philosophy of “safety-based” training, the MF102 series simulators are designed to teach students everything they need to know about OSHA’s and MSHA’s lockout standards. The simulators are equipped with electrical switch lockouts, and the revolutionary Safe-T-Bleed® system. Safe-T-Bleed® is the only system in the world which is designed to de-energize a hydraulic system and verify de-energization, and to permit air-purging, all without spilling a drop of oil. Lockout and tagout MUST be taught in schools and colleges to properly prepare students for the chal- lenges they will face in a tough, fast-paced, unrelenting production environment. 2 Safe-T-Bleed® is a registered trademark of Safe-T-Bleed® Corporation A partial list of the institutions who partner with us because they have a desire to deliver hydraulic training brilliantly: BJ Services Company - Texas Canadian Military (CFSEME) - Ontario, CANADA Des Moines Area Community College - Iowa Great Basin
    [Show full text]
  • Safety and Relief Valves
    Safety and Relief Valves Learning Outcome When you complete this module you will be able to: Discuss boiler safety valves for power boilers and heating boilers. Learning Objectives Here is what you will be able to do when you complete each objective: 1. State the ASME Code requirement for safety valves. 2. Describe the construction and operation of high pressure safety valves. 3. Describe the construction and operation of low pressure heating boiler safety valves and safety relief valves. 4. Describe the testing and repair of safety valves. 5. Describe the construction and operation of a temperature relief device. 1 BLRS 6022 INTRODUCTION Each boiler is designed to operate below a specific maximum pressure. The basic function of safety valves is to protect boilers against overpressure. Certain conditions, such as sudden loss of load or failure of automatic controls, can cause the boiler pressure to rapidly exceed the operating pressure. To prevent bursting of the boiler drum or other pressure parts due to this excessive pressure, at least one pressure operated safety valve must be installed on each boiler. When the pressure in the boiler approaches its maximum allowable value, the safety valve will open and release steam to the atmosphere, thus preventing any further increase in pressure. CODE REQUIREMENTS The ASME Code states that each steam boiler shall have at least one safety valve, and if the boiler has over 46.4 m2 (500 sq. ft.) of water heating surface, then two or more safety valves shall be installed. All boilers must be fitted with an approved type of pop safety valve of sufficient capacity to discharge all the steam that the boiler can evaporate, without permitting the pressure to rise more than 6% above the allowable working pressure.
    [Show full text]
  • 46 CFR Ch. I (10–1–00 Edition) § 52.01–115
    § 52.01±115 46 CFR Ch. I (10±1±00 Edition) under all normal and emergency condi- ceed 250 pounds per square inch, three tions. The secondary indicator may test cocks attached directly to the consist of a gage glass, or other accept- head or shell of a boiler may serve as able device. Where the allowance pres- the secondary water level indicator. sure exceeds 1724 kPa (250 psi), the gage (2) See paragraph (d) of this section glasses shall be of the flat type instead for restrictions on cock connections. of the common tubular type. (f) Pressure gages (modifies PG±60.6). (2) Gage glasses shall be in contin- Each double-ended boiler shall be fitted uous operation while the boiler is with two steam gages, one on either steaming. end on the boiler. (3) Double-ended firetube boilers (g) Salinometer cocks. In vessels oper- shall be equipped as specified in this ating in salt water, each boiler shall be paragraph and paragraph (e) of this equipped with a salinometer cock or section except that the required water valve which shall be fitted directly to level indicators shall be installed on the boiler in a convenient position. each end of the boiler. They shall not be attached to the (4) Externally fired flue boilers, such water gage or water column. as are used on central western river (h) High-water-level alarm. Each vessels, shall be equipped as specified watertube boiler for propulsion must in paragraphs (b) (1) through (3) of this have an audible and a visible high- section except that float gages may be water-level alarm.
    [Show full text]