Parr offers a series of high pressure burettes intended to introduce gas (commonly hydrogen) to a reactor at a constant pressure. The burettes consist of a high pressure reservoir equipped with an inlet valve, a pressure gage and a relief valve. A constant pressure regulator with a check valve, a connecting hose and a support stand are included with each pipette.The amount of gas consumed in a reaction can be determined by knowing the volume of the high pressure reservoir and observing the pressure drop in the reservoir during a reaction.

Parr high pressure burettes can be furnished in various sizes as shown in the adjoining table, each with a regulator to deliver gas to the reactor over the designated pressure range. The moles of gas shown in the table represent the amount of hydrogen that will be held in the burette at the maximum pressure. The deliverable volume will be a function of the difference in pressure between the pipette and the reactor. The size of the burette should be selected as large enough to provide sufficient gas to complete the reaction while still maintaining sufficient pressure in the burette to force gas into the reactor.

Reservoirs with larger volumes are available as are regulators with different delivery ranges. Modifications can be made to these basic systems to add an internal thermocouple to the reservoir and/or a pressure transducer for digital readout and/or recording.

High Pressure Gas Burettes
Burette			Delivery Pressure Range
Volume, mL	Maximum Pressure, psi	Total H2Volume, Moles	0-1800 psi	0-1200 psi	0-700 psi
150	1800	0.8	A2280HC	A2280HC2	A2280HC3
300	1800	1.5	A2281HC	A2281HC2	A2281HC3
500	1800	2.6	A2282HC	A2282HC2	A2282HC3
1000	1800	5.1	A2283HC	A2283HC2	A2283HC3
2250	1800	11.5	A2284HC	A2284HC2	A2284HC3
500	5000	7.1	A2285HC	A2285HC2	A2285HC3