The blood in the heart moved from one chamber to another chamber. If the AV ( artrio-ventricular valve) and SL ( semilunar valve) open at the same time, the blood will not be able to circulate and can flow backward. Thus the valves are there to stop the back-flow of blood and keep the circulation going.
it would disturb pressure gradients as it would mean same amount of pressure
No, the suction valves and discharge valves on a reciprocating compressor should not be open at the same time. If both valves are open simultaneously, it can lead to inefficient operation, potential damage to the compressor, and a loss of pressure. The design of the compressor relies on the sequential opening and closing of these valves to ensure proper gas flow and compression cycles.
Valve overlap.
There is a short time between the exhaust and intake stroke where all the valves are slightly open at the same time. This period of time is called valve overlap. This is because the intake valves are just starting to open as the exhaust valves are just finishing closing. This is done so flow through the engine can be maintained at engine operating speeds.
if you have water to the rest of the house and its the toilets only then either someone has turned off the valves under the toilets or the fill valves have both failed at the same time. [not very likely!!] cant be much of anything else.
Yes, both valves can be closed at the same time. (Look at a cardiac cycle diagram and look at time period of around 0.45 seconds)
No, both sets of heart valves are not open at the same time during the cardiac cycle. The atrioventricular valves (bicuspid and tricuspid) are open when the ventricles are relaxed (diastole) to allow blood to flow from the atria to the ventricles. The semilunar valves (aortic and pulmonary) are open when the ventricles contract (systole) to allow blood to be ejected into the arteries.
When playing a Trombone the player can make it slur. By blowing and moving the valves at the same time.
Camshafts are generally used to open and close valves at the correct time.
overlap
depends on the person
Exhaust valves open at the appropriate time to allow the burnt gasses to escape.