Precautions for butterfly valve procurement
What should be paid attention to when purchasing butterfly valves?
1、 The specification and category of butterfly valve shall meet the requirements of pipeline design documents.
(1).The model of butterfly valve should indicate the number requirements of national standard. If it is an enterprise standard, the relevant description of the model should be indicated.
(2). For the manufacturing standard of butterfly valve, the national standard number should be indicated. If it is an enterprise standard, the enterprise document should be attached to the purchase contract.
2、 Performance tests of butterfly valve
(1). When a certain specification of butterfly valve is manufactured in batches, an authoritative organization should be entrusted to carry out the following performance tests: ① Opening and closing moment of valve under working pressure condition; ② Under the working pressure condition, it can ensured that the valve is tightly closed during the continuous opening and closing times; ③ Detection of flow resistance coefficient of valve under the condition of pipeline water delivery.
(2). Before leaving the factory, the butterfly valve should be tested as follows: ① When the valve is opened, the valve body should withstand the internal pressure detection of double valve working pressure; ② When the valve is closed, both sides withstand 11 times of the valve working pressure value respectively, without leakage; however, the leakage value of the metal sealed butterfly valve should not greater than the relevant requirements.
3、 Internal and external anti-corrosion of butterfly valve
(1). For the inside and outside of the valve body (including the gearbox), shot blasting and rust removal should be carried out first, and then strive to electrostatic spray powder non-toxic epoxy resin with a thickness of more than 0.3mm. When it is difficult to electrostatic spray non-toxic epoxy resin on extra large valves, it can brush and spray similar non-toxic epoxy paint.
(2). The internal of valve body and all parts of valve plate should be fully anticorrosive. On the one hand, it will not rusty when immersed in water, and there will be no electrochemical corrosion between the two metals; on the other hand, the surface should be smooth to reduce the water resistance.
(3). The hygienic requirements for anticorrosive epoxy resin or paint in valve body, there should has a test report of corresponding authority. Chemical and physical properties should also meet relevant requirements.
4、 Packing and transportation of butterfly valve
(1). Both sides of the valve should be set with light plug plate for sealing.
(2). Small and medium diameter valves should be tied with straw ropes and transported in containers.
(3). Large diameter valves are also packed with wooden frame to avoid damage during transportation.
5、 Check the factory instruction of butterfly valve
(1) Butterfly valve is an equipment, and the following relevant data should be indicated in the factory instruction: valve specification; model; working pressure; manufacturing standard; valve body material; valve stem material; sealing material; valve shaft packing material; valve stem sleeve material; internal and external anti-corrosion material; operation starting direction; revolution; opening and closing torque under working pressure condition;
(2). Manufacturer's name; delivery date; delivery number: weight; hole diameter of connecting flange, hole number and center hole distance should be indicated with overall length, width and height control size in the way of diagram; effective opening and closing times; valve flow resistance coefficient; relevant data of valve delivery inspection and precautions for installation and maintenance, etc.
Bundor valve is a professional manufacturer of high quality butterfly valve. The main products are centre-pivoted butterfly valve and eccentric butterfly valve with guaranteed quality. Welcome to inquire.