Pumps pressure decrease

If a situation arises whereby formation fluid or gas enters the bore bole the driller will notice an increase in the total volume of mud. Other indications such as a sudden increase in penetration rate and a decrease in pump pressure may also indicate an influx. Much depends on a quick response of the driller to close in the well before substantial volumes of formation fluid have entered the borehole. Onoe the BOP is closed, the new mud gradient required to restore balance to the system can be calculated. The heavier mud is then circulated in through the kill line and the lighter mud and influx is circulated out through the choke line. Once overbalance is restored, the BOP can be opened again and drilling operations continue. 

Feed systems utilizing gravity are rarely used. Line pressure is usuaHy adequate for smaH systems. AuxHiary pumps are required in larger systems to assure proper flow through aH units and to avoid uneven flow should line pressure decrease as other demands for water or the process stream occur elsewhere in the facHity. 

Decrease in pump pressure. When less dense formation fluid enters the borehole, the hydrostatic head in the annulus is decreased thus, the pressure supplied by mud pumps is decreased. Although reduction in pump pressure... 

When the system pressure decreases to a point slightly below 600 psi, the spring forces the piston down and closes the pilot valve. When the pilot valve is closed, the fluid cannot flow directly to the return line. This causes the pressure to increase in the line between the pump and the regulator. This pressure opens the check valve, causing fluid to enter the system. 

The property of a fluid that resists any force such as atmospheric or pump pressure, tending to produce flow. Viscosity is a function of the fluids cohesive forces and generally decreases with increase in temperature. Also, friction losses decrease with increase in temperature. 

Assume that, when you press in the piston of a bicycle pump, the volume inside the pump is decreased from about 100. cm3 to 20. cm3 before the air flows into the tire. Suppose that the compression is isothermal estimate the final pressure of the compressed air in the pump, given an initial pressure of 1.00 atm. 

Pump-down of the antechamber, following solution experiments, involved sorption pumping and cryo-pumping resulting in the pressure decreasing from ambient to 10 Torr in 5 minutes. The resulting sample surfaces were subsequently examined by both LEFT) and AES after transfer back to the analysis-chamber. 

The water pump is another example of the Bernoulli effect, and is an everyday piece of equipment in most laboratories, for example being used during Buchner filtration. It comprises a piece of rubber tubing to connect the flask to be evacuated to a pump. Inside the pump, a rapid flow of water past one end of a small aperture inside the head decreases the pressure of the adjacent gas, so the pressure inside the pump soon decreases. 

We see this phenomenon in a different way when we look back at the phase diagram in Figure 5.6. The stable phase is liquid before applying a vacuum. After turning on the water pump, to decrease the applied pressure, the s.v.p. exceeds P(appiied)> and the solvent boils at a lower pressure. The bold arrow again indicates how a phase change occurs during a depression of the external pressure. 

For classic turbomolecular pumps, Km.dx is also dependent on the forevacuum pressure, decreasing at values of p orevSLC 10-3 mbar (the pressure at which the mean free path of the gas becomes less than the blade distance (see Figure 3.11)). 

When the oxygen partial pressure is raised to a critical value, the process becomes unstable An avalanche effect occurs since the rise in oxygen partial pressure decreases the pumping speed for the reactive gas. The target surface becomes fully oxidized. 

Mechanical pump oils (with their high vapor pressure) that drift into the diffusion pump can decrease its pumping efficiency. 

In contrast to this situation, the glow discharge of acetylene in a closed system extinguishes in a few seconds to few minutes depending on the size of the tube and the system pressure. This is because acetylene forms deposit and coats the wall of the reactor. In this process of LCVD (plasma polymerization) of acetylene, very little hydrogen or any gaseous species is created, and the LCVD of acetylene acts as a vacuum pump. When the system pressure decreases beyond a certain threshold value, the discharge cannot be maintained. 

The Lewis manostat operates on the same principle, except that a sintered glass disk is substituted for the capillary, and a column of mercury takes the place of the diver. The bulbs A and B are nearly half-filled with mercury, which should be boiled tmder reduced pressure to remove trapped gases. In operation, both stopcocks are left open until the pressure in the distillation system is slightly above the desired value, and then they are closed. The reference pressure above the mercury in A will cause it to flow into B as the pressure decreases, until the sintered glass plate is covered by the mercury. At this point, the system is isolated from the pump. As the pressure increases, the mercury flows back into A and pumping resumes. 

Leaks can be detected visually or by smell before even a pressure decrease is noticed. They can take place in different positions in the LC system, such as the column, the pump, the injection valve, or the detector. In case of leaks at the column or fittings, a leaky fitting should be tightened or replaced. The detector seal should be replaced if there is a leak at the detector. 

As the airship rises, atmospheric pressure decreases and the helium expands, as Boyle s law predicts. As the ship reaches the desired altitude, air is pumped into another bag called a ballonet. The pressure of the ballonet prevents the helium bags from expanding further, thus keeping the ship at that altitude. To descend, more air is pumped into the ballonet. This added pressure squeezes the helium bags, causing the volume to decrease and the density of the helium to increase. Also, the compressed air adds weight to the ship. The tiffing power of the helium is reduced and the airship moves downward. 

An automobile fuel tank has a filler pipe 2 ft in length with a diameter of 1.5 in. Estimate the amount of fuel lost (a) by molecular diffusion (if the gas cap is left off for a day) and (b) by advective pumping through a tank vent, when atmospheric pressure decreases from 30.0 to 29.5 in. Hg. Use an approximate diffusion coefficient of 0.1 cm2/sec. Assume the fuel is octane (C8H18, with a molecular weight of 114) having a vapor pressure of 0.015 atm at the ambient temperature of 70°F (21°C). The 70-liter tank is half full. 

Many substances which decompose when distilled at atmospheric pressure, distil without decomposition when the pressure is reduced. This results from the fact that the temperature at which a substance boils is markedly affected by the pressure. For example, benzophenone boils at 306° at 760 mm. pressure, and at 170° at 15 mm. pressure. The effect of change in pressure on the boiling-point increases rapidly as the pressure decreases. Stearic acid, for example, boils at 291° at 100 mm., at 232° at 15 mm., and at 155° under the best vacuum obtainable with a mercury pump. A difference of 85 mm. in pressure from 100 mm. to 15 mm. causes a change in boiling-point of 59°, whereas a difference of 15 mm. from 15 mm. to 0 mm. lowers the boiling-point 77°. 

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