It is common practice to specify the pump suction line one size larger than the pump discharge line in order to increase the Net Positive Suction Head available (NPSHA) to the pump. A smaller suction line the same pipe size as the discharge line would result in more pressure drop in the suction line and reduce the amount of head available to the suction side of the pump. This in turn would result in an operating point closer to cavitation of the pump.
Hi, A typical gas system comprises the digester cover, pressure and vacuum relief devices, water trap, flame trap, pressure regulator, gas meter, check valve, pressure gauges, waste gas burner and a gas holder. Mixing of digesters by means of gas re-circulation requires a compressor. The digester is covered to contain odours, maintain temperature, keeps air out and to collect the gas. Fixed covers are more usual than floating covers. During normal operation, there is a space for gas collection between the cover and the liquid surface of the digester contents. The cover of a digester has certain unique features that the operating staff must be aware of, for example, how the variation in pressure and the level inside the digester may affect the cover. The biggest danger associated with the operation of fixed cover digesters occurs when the pressure relief device mounted on top of the digester fails or the sludge overflow line blocks and the liquid level in the digester continues to rise. In such a situation, the excess gas pressure inside the digester can exceed the maximum design pressure and damage the cover or its mountings. Fixed covers can also be damaged by excess negative pressure (vacuum) or if the rate of waste sludge withdrawal exceeds the feed rate or the vacuum relief device fails. The function of the pressure relief device is to allow pressure that exceeds a safe level to escape from the digester. The manufacturer's specifications should provide the following information to enable the operating staff to control the gas system safely. (a) The system's normal operating pressure (mm water gauge). (b) The pressure at which the pressure relief device should operate. (c) The rated gas flow capacity of the pipes. A gas system generally comprises three pressure relief devices; one mounted on the cover of the digester, one on the gas holder and one situated at the end of the gas line before the gas burner. This device releases gas to the waste gas burner before the design gas pressure of the digester cover is reached. The vacuum relief device functions in the opposite manner to the pressure relief device and allows air to enter the digester in the event of the waste sludge being withdrawn too rapidly. Air should not, under normal conditions, be allowed to enter the digester because a mixture of air and methane is potentially highly explosive. Gas leaving the digester is almost saturated with water vapour. As the gas cools, the water vapour condenses causing problems. The problem is more severe when digesters are heated. To solve the problem it is essential to remove as much of the moisture as possible before the gas comes into contact with the gas system devices. For this reason, water traps should be located as close to the digester as possible. All piping should be sloped a minimum of 1% towards the water trap, which should be situated at a low point in the gas line. Flame traps are emergency devices installed in gas lines to prevent flames travelling back up the gas line (flashback) and reaching the digester. The flame trap generally consists of a box filled with stone or a metal grid. If a flame develops in the gas line, the temperature of the flame is reduced below the ignition point as it passes through the trap and the flame is extinguished. Pressure regulators are used when a lower pressure than the system operating pressure, is required for a specific device such as a boiler water heater or incinerator. Regulators maintain a constant gas pressure at the point of use The rate of gas production is probably the most sensitive process control indicator at the disposal of the operating staff. Gas meters should be regularly serviced so as to give accurate and reliable gas readings. Every effort should be made to have the gas meter calibrated every six months. Check valves (non-return valves) are installed in the gas line to allow gas flow in one direction only i.e. out of the digester. Gas pressure gauges indicate the pressure in the gas system and assist in locating any blockages in the line. If a blockage occurs, a pressure reading downstream will register a lower pressure than that of a gauge upstream. The pressure relief device at the waste gas burner safely flares excess gas to the atmosphere and thus reduces the potential for a dangerous accumulation of gas in the system. Many anaerobic digestion waste treatment plants have a means of storing excess gas. This can be in the form of either a floating roof on the digester or a separate gasholder. A mixture of biogas and air can be explosive. Methane gas in concentrations of between 5% and 15% in air by volume is explosive. Operating staff on waste treatment plants should ensure that no air is allowed to enter the digester or gasholder. All piping and equipment must be sealed properly to prevent gas from escaping to the outside. There must be no smoking and all electrical installations, including light switches, torches etc must be of the explosion-proof type, as the smallest spark could ignite escaped gases. Srinivas kasulla 09869179601 MUMBAI
Seal pots (sometime called condensate pots) are used to allow a liquid seal between the instrument and flowing gases such as steam. Their function is to keep the liquid level constant in the impulse tubes. For example, in boiler liquid level applications the high pressure (HP) side of a differential pressure transmitter is connected to the vapor space on top of the steam drum. Steam condenses in the chamber or seal pot and fills the impulse line with condensate. The seal pot is located to allow the condensate to drain back to the source thus keeping the liquid level constant.
It sounds like you are asking about calculating theoretical stages for distillation of a binary mixture using the McCabe-Thiele method, which includes calculation of the q line from the composition of the feed. The parameter q is the mole fraction of liquid in the feed and the slope of the q-line is q / (q - 1). The q line passes through the point defining the composition of the feed on the x=y line drawn on the diagram. For more details on the McCabe-Thiele method, see the attached link.
In boiler feed water line the NRV is normally installed between Pump and stop valve if the line is short and an another NRV is installed at boiler entrance and after stop valve if the line is long or pump is 10 to 15 m away from the boiler.
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Open the hood , look to the right, to the back, just to the left of the master cylinder, in the fuel line. relieve pressure on fuel line first. To reduce fire risk when you take off the filter.
you hook up a fuel pressure guage to it to check the fuel pressure
The larger line is the pressure line, the smaller line is return.
Restricted fuel return line or a faulty fuel pressure regulator.
There is a special adapter that is needed, you remove the fuel line to the fuel rail, install the special adapter and then install the fuel pressure gauge to the adapter and reinstall the fuel line to the adapter.
Well, i suppose if your injectors are using all of the fuel (super rare) then there would be no fuel coming back to the return fuel line. However, since you say there is NO fuel pressure, I would check out the fuel pressure regulators and the vacuum lines connected to them. The pressure regulators are located on the top of the engine and are directly in line to the fuel line. They are connected between the fuel rail (where all the injectors are fed from) and the metal fuel rail on top.
It doesn't have a vacuum line attached to the fuel pressure regulator.
NO!
With the engine running, remove the fuse or the relay for the fuel pump. The engine will stall soon and the fuel line won't have any pressure left.