The line from D to E is therefore the exhaust line, and that from E to A is the back pressure line or counter pressure line.
He may also locate the point of cut off, of release, the amount of back pressure, the degree of perfection of the vacuum in a condensing engine, and the amount of compression.
As a result, a portion of the piston movement and pressure which should be exerted on the crank after leaving the dead centre, will be exerted on it before it reaches the dead centre, thus causing a back pressure, involving a loss of power.
This condition, which in practice exists oftener than it is ordinarily thought, is called "back pressure.
These traps are, however, open to the objection that in the first place they do not prevent the fouling of the seals by back pressure, and in the second place they are not easily cleansable and may retain dirt in their large pockets.
It follows that an engine whose exhaust is arranged for a low speed cannot be run at a high speed without causing loss from back pressure.
Practically a perfect vacuum cannot be created, and there is a back pressure of 2 or 3 lbs.
There is then noback pressure on the exhaust steam, theoretically.
If the exhaust from the cylinder does not begin before the piston begins its return stroke, there will be back pressure due to the slowness with which the valve opens.
Now, the ~back pressure~ may be considerably reduced by exhausting into a condenser as represented by the card, fig.
The exhaust line being above the atmospheric line shows that the friction encountered by the steam in flowing through the exhaust pipe produces a back pressure of two lbs.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "back pressure" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.
