安全阀说明书SF-A42C

弹簧全启式安全阀

产品使用说明书

上海阀门厂有限公司

第 1 页 共 8 页

弹簧全启式安全阀使用说明书

1. 主要用途

该安全阀主要用于受压设备、容器和管道上作为超压保护装置。当设备超压并达到预定值(整定压力) 时，阀门开启，继后全量排放，以防止设备压力继续升高。当压力降低到规定值（排放压力）时，阀门关闭。从而保护设备安全运行。 2. 作用原理及其结构、特点 2.1作用原理

在被保护的承压系统处于正常工作状态时，作用在安全阀阀瓣上的弹簧力同介质作用力及阀瓣和阀座间密封力相平衡，安全阀处于密封状态。随着系统压力的逐渐升高，阀瓣和阀座间的密封力随之减小，当系统压力升高至规定值时，阀瓣和阀座间的密封力减小到零，阀瓣随即开启，安全阀开始排出介质。系统压力继续上升，当达到一定值时，阀瓣被提升到规定高度，安全阀处于全开状态，此时安全阀开始大量排出介质，达到安全阀的额定排放量。随着系统介质的不断排出，系统压力逐渐降低，当系统压力降低到规定值时，安全阀在弹簧的作用下，阀瓣自动关闭，并与阀座保持密封状态，避免系统介质过多排出，影响系统运行的经济性。 2.2 结构特点

2.2.1 阀座与阀体用螺纹连接，为可分离式，维修方便、经济。

2.2.2 采用调节圈结构，阀瓣在较小超压下就能够迅速地全开启，排出介质，从而达到保护设备安全运行的目的。

2.2.3 对阀瓣和导向套、阀杆和调整螺杆的材料进行合适的选择以及合理的间隙配合，保证阀瓣运动灵活。

2.2.4 阀瓣材料采用304不锈钢，密封性好，抗腐蚀能力强。阀座密封面堆焊STELLITE 硬质合金，表面精研后保证了安全阀的高密封性，延长了安全阀的使用寿命。

2.2.5 弹簧材料选用50CrV A ，可用于工作温度≤300℃的场合，弹簧加工工艺讲究，并进行严格的测试和检查。 3. 主要技术参数 3.1 遵循的标准

安全阀遵循API 520标准要求进行设计和制造。密封性能按API527标准的规定；进出口突面连接法兰标准按照ANSI B16.5。阀门结构长度按API526标准。 3.2 主要性能参数如下： 主要性能参数

整定压力 Mpa

排放压力 Mpa ≤1.1 Ps

回座压力 Mpa ≥90% Ps

密封压力 Mpa

最高工作温度

工作介质 气体等

Ps ℃

3.3 装配图

全启式安全阀SFA-42C

3.4 主要零件材料如下：

零件名称 材料

4. 储存、维护保养和安装要求

4.1 安全阀从出厂到安装使用之前如果搬运和存放欠妥当，会对阀门性能带来有害的影响，甚至使阀门遭受损伤。安全阀一般应装箱运输，并在箱内加以固定，尽量使安全阀竖直固定。运送时应避免剧烈振动。存放在干燥通风的室内。无论在运输或存放期间，其进出口都应堵塞。 4.2 如长期存放应作定期检查，消除污垢，并在加工面上涂以防锈油，防止生锈。 4.3 安装前应将阀门清洗干净，并消除在运输过程中造成的缺陷。 4.4 安装时必须仔细核对阀门上的标志和标牌，是否与使用要求相符。 4.5 安全阀应直立安装，并经常保持清洁，安装位置必须注意检修方便。 4.6 安装安全阀的设备和管道中的介质应保持清洁。

4.7 安全阀全部调整完毕后应进行铅封，以防止随意改变已调整好的状态。

阀 体 阀座 密封面 弹 簧 阀 盖 阀杆

50CrV

4.8 其它操作技术管理应按照国家劳动部颁布的有关安全规程办理。 5. 可能发生的故障及其消除办法。

安全阀使用不当，会造成阀门故障。这些故障如不及时消除，则会影响阀门的功能和寿命，甚至不能起到安全保护作用。

常见的故障有：

5.1 阀门泄漏：即在设备正常工作压力下，阀瓣与阀座密封面间发生超过允许程度的渗漏。其原因可能是：

（1） 脏物落到密封面上。把脏物冲去，清洁密封面；

（2） 密封面损伤。应根据损伤程度，采用研磨或车削后研磨的方法加以修复。修复后应保证密

封面平整度，其粗糙度应不低于Rz0.8；

（3） 由于装配不当或管道载荷等原因，使零件的同心度遭到破坏。应重新装配或设法消除管道

附加的载荷；

（4） 阀门开启压力与设备正常工作压力太接近，造成密封比压力过低。当阀门受振动或介质压

力波动时容易发生泄漏。应根据承压设备超压保护要求，调整开启压力；

（5） 弹簧松驰从而使整定压力降低从而引起阀门泄漏。可能是由于高温或腐蚀等原因所造成，

应根据引起泄漏的原因采取调整弹簧提高整定压力或更换弹簧甚至调换阀门（如果属于选用不当的话）等措施。如果仅仅是由于调整不当所引起，则只需把调整螺杆适当拧紧。 5.2 阀门启闭不灵活。其主要原因可能是：

（1）调节圈调整位置不当，致使阀门开启过程拖长或回座迟缓，应重新加以调整；

（2）内部运动零件有卡阻现象，这可能是由于装配不当，脏物混入或零件腐蚀等原因所造成，应查明原因消除之；

（3）排放管道压力过大，排放时建立起较大背压，使阀门开不足。应减小排放管道阻力。 5.3 阀门振荡，即阀瓣频繁启闭。其可能的原因如下：

(1) 阀门排放能力过大（相对于必需排量而言）。在选用阀门时，应选用阀门的额定排量尽

可能接近设备的必需排放量；

(2) 进口管道口径太小或阻力太大。应使进口管内径不小于阀门进口通径或者减小进口管道

阻力；

(3) 排放管道阻力过大，造成排放时过大的背压。应降低排放管道阻力； (4) 弹簧刚度太大。应改用刚度较小的弹簧；

(5) 调节圈调整不当，使回座压力过高。应重新调整调节圈位置。

O & M Manual

For

Spring Loaded Safety Valve

Shanghai Valve Factory Co., LTD

O & M manual for Spring Loaded Safety valve

1. Usage

The safety valve is used as an overpressure protection for a pressurized equipment, vessel or pipe. As the pressure in the equipment is higher than a set pressure, the valve opens and then fully discharges. As the pressure is lower than the blow down pressure, it closes to protect the equipment and to operate safely.

2. Working Principle and Structure Features 2.1 Working Principle

Under normal working condition in a pressurized system when a spring force exerted on a valve disc, and the medium pressure and a seating force between valve disc and valve seat are kept in balance, the safety valve will keep in close position. If the system gradually increases the pressure, the seating force between the valve disc and valve seat decreases accordingly. When pressure in the system goes up to a set pressure, the seating force reaches to zero. At this moment the valve disc immediately opens discharging the medium. If the pressure in system keeps going on up to a certain value, the safety valve fully opens. Under such condition large quantity of medium will go out and reach the rated discharging capacity. As the medium discharges out, the pressure gradually reduces, While the pressure reaches to the blow down pressure, the valve disc automatically shuts down by means of spring force and keeps seating with valve seat, preventing the equipment from undue discharging medium and influencing normal operation. Structure Features

The valve body and disc are renewable by means of threads. This is convenient in maintenance and economic.

A adjusting ring is used So that the disc can quickly open and discharge at a small over-pressure and keep the equipment safe.

The materials of the valve disc and guide sleeve, stem and adjusting bolt are properly chosen with reasonable clearances to ensure movement of the valve disc smoothly.

The valve disc is made of 304austenitic stainless steel with high excellent corrosion resistance. The seating surface of valve seat is overplayed with STELLITE and lapped to ensure excellent seal reliability and to prolong service life of valve.

The spring is made of material 50CrVA and carefully fabricated, strictly inspected and tested. It can be used at temperature≦300℃. 3. Main Technical Parameters 3.1 Applicable Standards

The valve is Designed and manufactured in accordance with API 520. Its leakage rate

confirms to API 527. Its RF flange ends and Face-to-face dimensions are as per ANSI B16.5 and API 526 respectively. 3.2 Its specification as follows:

Set P. Mpa

Discharge P.

Mpa ≤1.1 Ps

Blow down P.

Mpa ≥90% Ps

Closure Test P.

Mpa 90%Ps

Working Temp. ≦

Working medium Air etc.

Ps

300℃

3.3 Assemble Drawing

The Safety valve SFA-42C is shown on Fig 1.

Fig 1 Safety valve SFA-42C

3.4 Materials of Main Parts Part name

Body

Seat 304

Seating sur. Stellite

Spring Bonnet Stem 2Cr13

50CrV A WCB

4. Storing, Maintenance and Installation

4.1 In order to prevent from damage during transportation, handling and storage the safety valve shall

be packed in a wooden crate and firmly fixed in vertical direction. Intensive vibration must be avoided during transportation. It shall be stored in a dry and well-ventilated room. Its inlet and outlet both shall be plugged with plastic covers during transportation or storage.

4.2 All machined surfaces shall be cleaned and then laid with anti-rusting oil or grease, moreover

periodic inspection shall be carried out provided the valve will be stored for long time.

4.3 Before installation the safety valve shall be cleaned up and any defect shall be eliminated resulted

during transportation.

4.4 Carefully checking if its nameplate and marks are correct.

4.5 The safety valve shall be vertically installed, the stem is upward and convenience in maintenance

shall be taken into consideration.

4.6 The equipment fitted with safety valve and the medium in pipe shall keep clean.

4.7 A lead seal shall be made after adjustment of the safety valve to avoid to randomly changing of

adjusted condition.

4.8 The safety valve should be in accordance with the safety regulations issued by the National Labor

Ministry.

5. Possible trouble and remedy Possible trouble and remedy

Any trouble with the safety valve caused by incorrect use and mal-operation shall be eliminated at any time. Otherwise it will have an adverse effect on its function and service life, even refuse to act as an overpressure protection.

The troubles usually meeting are as follows: 5.1 Valve leakage.

Leakage over permissible quantity from seating surfaces between valve disc (4) and nozzle (2) appears at a normal working pressure. The causes probably include the following: (1) The seating surfaces are dirt. Solution: cleaning up the seating surfaces.

(2) The seating surface are damaged. Solution: repairing the damaged surfaces by means of lapping the surfaces, or first machining, grinding and then lapping them as the case may be. The repaired surfaces must be flat with roughness not less than Rz0.8.

(3) Misalignment of parts caused by incorrect assembly or piping load, etc. Solution: re-assemble it or getting rid of additional piping load.

(4) Its set pressure is too close to normal working pressure so that a seal off force ratio is too small. In this case the valve is easy to leak while the valve is vibrating or a medium pressure is fluctuating. Solution: Readjusting its set pressure according to the requirement of the equipment’s overpressure protection.

(5) The set pressure decreases because of a loose spring (6). This probably results from high temperature or corrosion. Solution: following respective measures may be taken according to different causes: increasing the set pressure by adjusting spring, or displace the spring, or even displace the valve if the valve is incorrectly selected. In case of incorrect adjustment of spring, adjusting properly the adjusting bolt.

5.2 Not nimble open –close actions of valve. The causes may be as follows:

(1) The adjusting rings is not in right position so that opening valve is elongated and reseating is delayed. Solution: readjustment.

(2) Internal moving parts are stuck. This maybe results from improper assembly, or foreign

matters, or corroded parts. Solution: find out cause and then put it right.

(3) The pressure in discharging pipe is too high resulting in undue back- pressure. Solution: reducing the resistance in discharging pipe.

(2) Internal moving parts stick. Solution: make inspection and elimination.

5.3 The disc frequently opens and closes so that the valve is shattering. The possible causes are as follows:

(1) The discharge capacity of the valve is much higher than necessary one. In selection of valve its rated discharging capacity should be close to necessary discharge of the equipment as far as possible.

(2) The diameter of an inlet pipe is too small or its flow resistance too high. Solution: making the inner diameter of the inlet pipe not less than inlet diameter of valve, or reduce its resistance in the pipe.

(3) A big flow resistance in discharging pipe makes back pressure in discharging big. Solution: reducing flow resistance in discharging pipe.

(4) The spring (6) is too stiff. Solution: displace it with a spring of less stiffness.

(5) The adjusting ring is improperly adjusted so that the reseat pressure is too high. Solution: readjusting the adjusting ring.