A butterfly valve consists basically of a disc pivoted across the bore of a ring body having the same radial dimensions as the pipe in which it is fitted.According to the above sentence, which of the following statements is not true?（）

相似题目

• A variable displacement system of hydraulic drives consists of （）.

  A . a variable displacement axial piston pump B . a constant displacement axial piston pump C . a reciprocating piston pump D . a centrifugal pum

  查看最佳答案

• In setting the valves on a steam-smothering system on a tank vessel，the master control valve to cargo tanks should be（）.

  A . open and individual tank valves open B . open and the individual tank valves closed C . closed and the individual tank valves closed D . closed and the individual tank valves ope

  查看最佳答案

• A bridle for an ocean tow consists of（）.

  A . two chains of equal length B . a single nylon pendant rove through a heavy ring free to move on the pendant C . two long legs of wire rope shackled to a fishplate D . a single length of heavy chain with both ends secured on deck to welded pad eye

  查看最佳答案

• A more sophisticated pressure reducing valve incorporates a pilot valve which controls the fluid above the valve operating piston in response to downstream pressureThe bold and italic word “which” means （）.

  A . a pressure reducing valve B . a pilot valve C . an operating piston D . downstream pressure

  查看最佳答案

• In setting the valves on a steam-smothering system on a tanker，the master control valve to cargo tanks should be（）.

  A . open and individual tank valves open B . open and the individual tank valves closed C . closed and the individual tank valves closed D . closed and the individual tank valves ope

  查看最佳答案

• A ruptured diaphragm in a thermostatic expansion valve will cause the valve to （）.

  A . open B . close C . remain in its position D . flood the evaporator with refrigerant

  查看最佳答案

• How many TDMA frames consist of a GPRS multiframe？（）

  A . 26 B . 51 C . 52 D . 1036

  查看最佳答案

• Which of the following statements concerning butterfly valves is correct?（）

  A . Special tools are required for lapping or grinding B . It is impossible to throttle flow with a butterfly valve C . To close the valve, it is only necessary to turn the handle a quarter of a turn D . The butterfly valve should never be used in a freshwater system

  查看最佳答案

• A relief valve for a cargo pump is generally installed（）.

  A . after the discharge valve B . between the pump and discharge valve C . after the suction valve D . between the pump and suction valve

  查看最佳答案

• The needle valve in a fuel valve will （） when the fuel pressure action on the needle valve tapered face exerts a force lower than that of the spring compression.

  A . be jammed B . be opened C . be seated D . be broke

  查看最佳答案

• Increasing the valve clearance between a valve stem and rocker arm, will result in the valve （）

  A . closing later B . opening sooner C . staying open for a shorter period of time D . staying open for a longer period of time

  查看最佳答案

• A light signal consisting of three flashes means （）.

  A . I am in doubt as to your actions B . My engines are full speed astern C . I desire to overtake you D . I am operating astern propulsio

  查看最佳答案

• A swing check valve is used in a pipeline to （）.

  A . maintain a preset pressure on the line B . closely regulate the amount of flow C . relieve excessive pressure on the line D . allow flow in one direction only

  查看最佳答案

• A thermostatic expansion valve is properly controlling evaporator superheatAdjusting this valve to lower the superheat will result in a/an （）.

  A . evaporator pressure decrease B . evaporator coil over-feed C . evaporator capacity increase D . expansion valve diaphragm rupture

  查看最佳答案

• A device fitted over the discharge opening on a relief valve consisting of one or two woven wire fabrics is called a（）.

  A . flame stopper B . flame screen C . flame filter D . flame restrictor

  查看最佳答案

• A cracked diaphragm in a thermostatic expansion valve will cause the valve to （）.

  A . return to a neutral position B . flood the evaporator C . open D . close

  查看最佳答案

• A check valve is another name for （）.

  A . a test valve B . an inspection valve C . a stop valve D . a non-return valve

  查看最佳答案

• A VC-4-4c consists of （）.

  A .  an STM-16 B .  any four VC-4s C .  four contiguous VC-4s D .  four contiguous STM-4s E .  two groupings of four VC-4

  查看最佳答案

• A solenoid valve used in a refrigeration system should be installed （）.

  A . with the axis of the solenoid horizontal, sensing temperature of the box, and upstream of the thermal expansion valve B . upright, sensing temperature of the box, and upstream of the thermal expansion valve C . upright, sensing temperature of the box, and downstream of the thermal expansion valve D . upright, sensing heat of the tail coil, and upstream of the thermal expansion valve

  查看最佳答案

• A categoricalsyllogism consist of three parts:()?

  查看最佳答案

• Ownership and management of a corporation consists of ( ).

  查看最佳答案

• Translate the following sentence.You always hear in sports that the butterflies go away after a while, but Elizabeth’s butterflies just kept flapping.

  查看最佳答案

• What does a resume usually consist?

  查看最佳答案

• On the day of my wedding, I wore a pair of Ferragamowith pearls in the shape of a butterfly.

  查看最佳答案